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Background: The Knee injury and Osteoarthritis Outcome Score–Anterior Cruciate Ligament (KOOS-ACL) is a short form version of the KOOS, developed to target populations of young active patients with ACL tears. The KOOS-ACL consists of 2 subscales: Function (8 items) and Sport (4 items). The KOOS-ACL was developed and validated using data from the Stability 1 study from baseline to postoperative 2 years. Purpose: To validate the KOOS-ACL in an external sample of patients matching the outcome’s target population. Study Design: Cohort study (diagnosis); Level of evidence, 1. Methods: The Multicenter Orthopaedic Outcomes Network group cohort of 839 patients aged 14 to 22 years who tore their ACLs while playing sports was used to assess internal consistency reliability, structural validity, convergent validity, responsiveness to change, and floor/ceiling effects of the KOOS-ACL at 4 time points: baseline and postoperative 2, 6, and 10 years. Detection of treatment effects between graft type (hamstring tendon vs bone–patellar tendon–bone) were also compared between the full-length KOOS and KOOS-ACL. Results: The KOOS-ACL demonstrated acceptable internal consistency reliability (α = .82-.89), structural validity (Tucker-Lewis index and comparative fit index = 0.98-0.99; standardized root mean square residual and root mean square error of approximation = 0.04-0.07), convergent validity (Spearman correlation with International Knee Documentation Committee subjective knee form = 0.66-0.85; Western Ontario and McMaster Universities Osteoarthritis Index function = 0.84-0.95), and responsiveness to change across time (large effect sizes from baseline to postoperative 2 years; d = 0.94 [Function] and d = 1.54 [Sport]). Stable scores and significant ceiling effects were seen from 2 to 10 years. No significant differences in KOOS or KOOS-ACL scores were detected between patients with different graft types. Conclusion: The KOOS-ACL shows improved structural validity when compared with the full-length KOOS and adequate psychometric properties in a large external sample of high school and college athletes. This strengthens the argument to use the KOOS-ACL to assess young active patients with ACL tears in clinical research and practice.

Background: A primary goal of anterior cruciate ligament reconstruction (ACLR) is to reduce pathologically increased anterior and rotational laxity of the knee, but the effects of residual laxity on patient-reported outcomes (PROs) after ACLR remain unclear. Hypothesis: Increased residual laxity at 2 years postoperatively is predictive of a higher risk of subsequent ipsilateral knee surgery and decreases in PRO scores from 2 to 6 years after surgery. Study Design: Cohort study; Level of evidence, 2. Methods: From a prospective multicenter cohort, 433 patients aged 6 mm) in laxity at 2 years postoperatively. Multiple linear regression models were built to determine the relationship between 2-year postoperative knee laxity and 2- to 6-year change in PROs while controlling for age, sex, body mass index, smoking status, meniscal and cartilage status, and graft type. Results: A total of 381 patients (87.9%) were available for follow-up 6 years postoperatively. There were no significant differences in risk of subsequent knee surgery based on residual knee laxity. Patients with a difference >6 mm in side-to-side anterior laxity at 2 years postoperatively were noted to have a larger decrease in PROs from 2 to 6 years postoperatively ( P < .05). No significant differences in any PROs were noted among patients with a difference Conclusion: The presence of a residual side-to-side KT-1000 arthrometer difference 6 mm in side-to-side anterior laxity were noted to have significantly decreased PROs at 6 years after ACLR.

Background: Although graft choice may be limited in the revision setting based on previously used grafts, most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome. Hypothesis: In the ACL revision setting, there would be no difference between autograft and allograft in rerupture rate and patient-reported outcomes (PROs) at 6-year follow-up. Study Design: Cohort study; Level of evidence, 2. Methods: Patients who had revision surgery were identified and prospectively enrolled in this cohort study by 83 surgeons over 52 sites. Data collected included baseline characteristics, surgical technique and pathology, and a series of validated PRO measures. Patients were followed up at 6 years and asked to complete the identical set of PRO instruments. Incidence of additional surgery and reoperation because of graft failure were also recorded. Multivariable regression models were used to determine the predictors (risk factors) of PROs, graft rerupture, and reoperation at 6 years after revision surgery. Results: A total of 1234 patients including 716 (58%) men were enrolled. A total of 325 (26%) underwent revision using a bone-patellar tendon-bone (BTB) autograft; 251 (20%), soft tissue autograft; 289 (23%), BTB allograft; 302 (25%), soft tissue allograft; and 67 (5%), other graft. Questionnaires and telephone follow-up for subsequent surgery information were obtained for 809 (66%) patients, while telephone follow-up was only obtained for an additional 128 patients for the total follow-up on 949 (77%) patients. Graft choice was a significant predictor of 6-year Marx Activity Rating Scale scores ( P = .024). Specifically, patients who received a BTB autograft for revision reconstruction had higher activity levels than did patients who received a BTB allograft (odds ratio [OR], 1.92; 95% CI, 1.25-2.94). Graft rerupture was reported in 5.8% (55/949) of patients by their 6-year follow-up: 3.5% (16/455) of patients with autografts and 8.4% (37/441) of patients with allografts. Use of a BTB autograft for revision resulted in patients being 4.2 times less likely to sustain a subsequent graft rupture than if a BTB allograft were utilized ( P = .011; 95% CI, 1.56-11.27). No significant differences were found in graft rerupture rates between BTB autograft and soft tissue autografts ( P = .87) or between BTB autografts and soft tissue allografts ( P = .36). Use of an autograft was found to be a significant predictor of having fewer reoperations within 6 years compared with using an allograft ( P = .010; OR, 0.56; 95% CI, 0.36-0.87). Conclusion: BTB and soft tissue autografts had a decreased risk in graft rerupture compared with BTB allografts. BTB autografts were associated with higher activity level than were BTB allografts at 6 years after revision reconstruction. Surgeons and patients should consider this information when choosing a graft for revision ACL reconstruction.

Background: The incidence of posttraumatic osteoarthritis (PTOA) based on clinical radiographic grading criteria at 10 years after anterior cruciate ligament (ACL) reconstruction (ACLR) has not been well-defined in a prospective cohort of young athletic patients. Hypothesis: Among young athletic patients, there is a high incidence of clinical radiographic PTOA at 10 years after ACLR. Additionally, there is a significant difference in clinical radiographic osteoarthritis (OA) changes (joint space narrowing and osteophyte formation) between ACL-reconstructed and contralateral knees at 10 years. Study Design: Case series; Level of evidence, 4. Methods: The first 146 patients in an ongoing nested cohort study of the Multicenter Orthopaedic Outcomes Network (MOON) prospective cohort presented for a minimum 10-year follow-up. Included patients had a sports-related ACL injury, were aged Results: Interrater reliability was substantial for the IKDC (Gwet Agreement Coefficient [AC] 1 = 0.71), moderate for the KL (0.48), and almost perfect for the OARSI (0.84) grading systems. Among patients with a contralateral radiographically normal knee, the 10-year incidence of clinical radiographic PTOA after ACLR was 37% as defined by osteophytes and 23% as defined by joint space narrowing. The maximum side-to-side difference in the OARSI osteophyte grade in the medial or lateral compartment was 0 in 65% of patients, 1 in 20%, and ≥2 in 15%. The maximum side-to-side difference in the OARSI joint space narrowing grade was 0 in 77% of patients, 1 in 19%, and ≥2 in 4%. Conclusion: In young active patients, the 10-year incidence of clinical radiographic PTOA after ACLR was 37% as defined by osteophytes and 23% as defined by joint space narrowing. The mean difference in the degree of osteophyte formation (≤1 grade in 85%) and joint space narrowing (≤1 grade in 96%) between the ACL-reconstructed and contralateral knees was small. Registration: NCT02717559 (ClinicalTrials.gov identifier)

Background: Meniscal preservation has been demonstrated to contribute to long-term knee health. This has been a successful intervention in patients with isolated tears and tears associated with anterior cruciate ligament (ACL) reconstruction. However, the results of meniscal repair in the setting of revision ACL reconstruction have not been documented. Purpose: To examine the prevalence and 2-year operative success rate of meniscal repairs in the revision ACL setting. Study Design: Case-control study; Level of evidence, 3. Methods: All cases of revision ACL reconstruction with concomitant meniscal repair from a multicenter group between 2006 and 2011 were selected. Two-year follow-up was obtained by phone and email to determine whether any subsequent surgery had occurred to either knee since the initial revision ACL reconstruction. If so, operative reports were obtained, whenever possible, to verify the pathologic condition and subsequent treatment. Results: In total, 218 patients (18%) from 1205 revision ACL reconstructions underwent concurrent meniscal repairs. There were 235 repairs performed: 153 medial, 48 lateral, and 17 medial and lateral. The majority of these repairs (n = 178; 76%) were performed with all-inside techniques. Two-year surgical follow-up was obtained on 90% (197/218) of the cohort. Overall, the meniscal repair failure rate was 8.6% (17/197) at 2 years. Of the 17 failures, 15 were medial (13 all-inside, 2 inside-out) and 2 were lateral (both all-inside). Four medial failures were treated in conjunction with a subsequent repeat revision ACL reconstruction. Conclusion: Meniscal repair in the revision ACL reconstruction setting does not have a high failure rate at 2-year follow-up. Failure rates for medial and lateral repairs were both

Background: The cause of subsequent surgery after anterior cruciate ligament (ACL) reconstruction varies, but if risk factors for specific subsequent surgical procedures can be identified, we can better understand which patients are at greatest risk. Purpose: To report the incidence and types of subsequent surgery that occurred in a cohort of patients 6 years after their index ACL reconstruction and to identify which variables were associated with the incidence of patients undergoing subsequent surgery after their index ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Patients completed a questionnaire before their index ACL surgery and were followed up at 2 and 6 years. Patients were contacted to determine whether any underwent additional surgery since baseline. Operative reports were obtained, and all surgical procedures were categorized and recorded. Logistic regression models were constructed to predict which patient demographic and surgical variables were associated with the incidence of undergoing subsequent surgery after their index ACL reconstruction. Results: The cohort consisted of 3276 patients (56.3% male) with a median age of 23 years. A 6-year follow-up was obtained on 91.5% (2999/3276) with regard to information on the incidence and frequency of subsequent surgery. Overall, 20.4% (612/2999) of the cohort was documented to have undergone at least 1 subsequent surgery on the ipsilateral knee 6 years after their index ACL reconstruction. The most common subsequent surgical procedures were related to the meniscus (11.9%), revision ACL reconstruction (7.5%), loss of motion (7.8%), and articular cartilage (6.7%). Significant risk factors for incurring subsequent meniscus-related surgery were having a medial meniscal repair at the time of index surgery, reconstruction with a hamstring autograft or allograft, higher baseline Marx activity level, younger age, and cessation of smoking. Significant predictors of undergoing subsequent surgery involving articular cartilage were higher body mass index, higher Marx activity level, reconstruction with a hamstring autograft or allograft, meniscal repair at the time of index surgery, or a grade 3/4 articular cartilage abnormality classified at the time of index ACL reconstruction. Risk factors for incurring subsequent surgery for loss of motion were younger age, female sex, low baseline Knee injury and Osteoarthritis Outcome Score symptom subscore, and reconstruction with a soft tissue allograft. Conclusion: These findings can be used to identify patients who are at the greatest risk of incurring subsequent surgery after ACL reconstruction.

Objectives: 1) To prospectively determine the incidence of post-traumatic osteoarthritis (PTOA) at 10 years after anterior cruciate ligament reconstruction (ACLR) in young athletic patients on clinical radiographs: and 2) to determine the average difference in clinical radiographic osteoarthritis changes (joint space narrowing [JSN] and osteophyte formation) between the ACLR and contralateral ACL-intact knees. Methods: The first 146 patients in an ongoing prospective nested cohort study within the Multicenter Orthopaedic Outcomes Network (MOON) cohort returned onsite for minimum 10-year follow-up. Inclusion criteria were that patients had a sports-related ACL injury, no prior history of knee surgery, no contralateral ACL injury, and were less than 33 years of age at the time of their ACLR. Bilateral knee standing metatarsophalangeal (MTP) view radiographs were obtained and graded by International Knee Documentation Committee (IKDC), Osteoarthritis Research Society International (OARSI), and modified Kellgren-Lawrence (KL) criteria by two blinded reviewers. Inter-rater reliability was determined for all clinical radiographic OA grading criteria. The incidence and severity of ipsilateral and contralateral knee osteoarthritis were determined among patients without a contralateral ACL injury before 10-year follow-up (n=133). Results: Inter-rater reliability was substantial for IKDC (Gwet’s AC1 = 0.71), moderate for KL (0.48) and almost perfect for OARSI (0.84) grading systems. The 10-year incidence of PTOA on clinical radiographs in the ACLR knee was 43% as defined by osteophytes and 27% as defined by JSN (Table 1). In the contralateral ACL-intact knee, the incidence of osteophyte-defined OA was 10% and JSN-defined OA was 5%. The maximum side-to side difference in medial or lateral compartment OARSI osteophyte grade was 0 in 65% of patients, 1 in 20%, and 2+ in 15% (Figure 1) (Table 2). The maximum difference in OARSI JSN grade was 0 in 77% of patients, 1 in 19%, and 2+ in 4% (Figure 2) (Table 2). Conclusions: In young active patients, the 10-year incidence on clinical radiographs of osteophyte-defined PTOA after ACLR is 43% and JSN-defined PTOA is 27%. The average difference in degree of osteophyte formation (≤1 grade in 85%) and JSN (≤1 grade in 96%) between the ACLR knee and contralateral ACL-intact knee is small.

Background: Anterior cruciate ligament (ACL) revision cohorts continually report lower outcome scores on validated knee questionnaires than primary ACL cohorts at similar time points after surgery. It is unclear how these outcomes are associated with physical activity after physician clearance for return to recreational or competitive sports after ACL revision surgery. Hypotheses: Participants who return to either multiple sports or a singular sport after revision ACL surgery will report decreased knee symptoms, increased activity level, and improved knee function as measured by validated patient-reported outcome measures (PROMs) and compared with no sports participation. Multisport participation as compared with singular sport participation will result in similar increased PROMs and activity level. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 1205 patients who underwent revision ACL reconstruction were enrolled by 83 surgeons at 52 clinical sites. At the time of revision, baseline data collected included the following: demographics, surgical characteristics, previous knee treatment and PROMs, the International Knee Documentation Committee (IKDC) questionnaire, Marx activity score, Knee injury and Osteoarthritis Outcome Score (KOOS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). A series of multivariate regression models were used to evaluate the association of IKDC, KOOS, WOMAC, and Marx Activity Rating Scale scores at 2 years after revision surgery by sports participation category, controlling for known significant covariates. Results: Two-year follow-up was obtained on 82% (986 of 1205) of the original cohort. Patients who reported not participating in sports after revision surgery had lower median PROMs both at baseline and at 2 years as compared with patients who participated in either a single sport or multiple sports. Significant differences were found in the change of scores among groups on the IKDC ( P < .0001), KOOS-Symptoms ( P = .01), KOOS–Sports and Recreation ( P = .04), and KOOS–Quality of Life ( P < .0001). Patients with no sports participation were 2.0 to 5.7 times more likely than multiple-sport participants to report significantly lower PROMs, depending on the specific outcome measure assessed, and 1.8 to 3.8 times more likely than single-sport participants (except for WOMAC-Stiffness, P = .18), after controlling for known covariates. Conclusion: Participation in either a single sport or multiple sports in the 2 years after ACL revision surgery was found to be significantly associated with higher PROMs across multiple validated self-reported assessment tools. During follow-up appointments, surgeons should continue to expect that patients who report returning to physical activity after surgery will self-report better functional outcomes, regardless of baseline activity levels.

Objectives: The prevalence of patellofemoral joint (PFJ) osteoarthritis (OA) ranges from 8-47% 7-10 years after anterior cruciate ligament reconstructions (ACLR) using bone-patellar tendon-bone (BTB) autograft. In performing BTB ACLR, some hypothesize that either trauma caused by harvest of the patellar bone autograft or altered biomechanics lead to PFJ post traumatic osteoarthritis (PTOA). Our objective was to evaluate by 3T MRI whether the ACLR knees had more signs of early PTOA compared to the contralateral knee within the MOON nested cohort. We hypothesize that a BTB autograft harvested using a minimally traumatic technique will not increase the risk of PFJ OA. Methods: MRIs of operative and contralateral uninjured knees were collected in 60 patients (28 males, mean age 21 years) from a single site in the Multicenter Orthopaedic Outcomes Network (MOON) nested cohort at minimum 2 years post BTB ACLR. Harvesting the patellar block for the BTB autograft was performed using an oscillating saw with a narrow blade, being careful not to extend the cut into the posterior cortex of the patella, and with gentle elevation of the bone block with an osteotome. MRI was performed at 3T (Philips, Achieva) and the imaging protocol included intermediate-weighted sagittal turbo spin-echo (TSE) imaging, axial and coronal fat-saturated TSE imaging, and 3D coronal gradient echo imaging. Structural MRI assessment of the knees was performed using the MRI Osteoarthritis Knee Score (MOAKS) semi-quantitative scoring system by a board-certified musculoskeletal radiologist. The prevalence of cartilage defects in each knee compartment (medial, lateral, patellofemoral), meniscal tears (medial, lateral; yes/no), bone marrow edema-like lesions (BMEL; medial, lateral, patellofemoral; yes/no), effusion (yes/no) and Hoffa synovitis (yes/no) were compared between the reconstructed and contralateral uninjured knees. Hypothesis testing was performed for the PF joint using a logistic regression model where the dependent variable was presence/absence of cartilage loss and the independent variable was knee status (surgical or contralateral). Results: There were no significant differences in the prevalence of cartilage defects (any lesions or full thickness loss) in the PFJ between the surgical BTB ACLR knees and the uninjured non-operative contralateral control knees. 38.3% of BTB ACLR knees had PFJ cartilage defects versus 31.7% of contralateral control knees with PFJ cartilage defects (p>0.05) (Table 1). The BTB ACLR knees had more cartilage defects in the medial and lateral tibiofemoral compartments, more meniscal tears, BMEL, effusion and Hoffa synovitis, than the contralateral knees. Figure 1 shows examples of PFJ cartilage defects on MRI for the reconstructed and contralateral uninjured knees. At 2 years follow-up, KOOS symptoms, sports, pain, and activities of daily living scores were maintained at a high level ranging from 88-98. Conclusion: Although prior studies suggest BTB ACLR increases the risk of PFJ OA, the current study shows no difference in MRI signs of early PTOA in the PFJ. Cartilage defects comparing reconstructed vs. contralateral uninjured knees 2 years after surgery based on MRI were not different. These results should be used in shared decision making with athletes in choosing the appropriate autograft during reconstruction. Future studies will investigate the influence of cartilage defects found in the medial and lateral compartments further.

Background: The Knee injury and Osteoarthritis Outcome Score (KOOS) has demonstrated inferior psychometric properties when compared with the International Knee Documentation Committee (IKDC) subjective knee form when assessing outcomes after anterior cruciate ligament (ACL) reconstruction. The KOOS, Joint Replacement (KOOS, JR) is a validated short-form instrument to assess patient-reported outcomes (PROs) after knee arthroplasty, and the purpose of this study was to determine if augmenting the KOOS, JR with additional KOOS items would allow for the creation of a short-form KOOS-based global knee score for patients undergoing ACL reconstruction, with psychometric properties similar to those of the IKDC. Hypothesis: An augmented version of the KOOS, JR could be created that would demonstrate convergent validity with the IKDC but avoid the ceiling effects and limitations previously noted with several of the KOOS subscales. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Based on preoperative and 2-year postoperative responses to the KOOS questionnaires from a sample of 1904 patients undergoing ACL reconstruction, an aggregate score combining the KOOS, JR and the 4 KOOS Quality of Life subscale questions, termed the KOOSglobal, was developed. Psychometric properties of the KOOSglobal were then compared with those of the IKDC subjective score. Convergent validity between the KOOSglobal and IKDC was assessed with a Spearman correlation (ρ). Responsiveness of the 2 instruments was assessed by calculating the pre- to postoperative effect size and relative efficiency. Finally, the presence of a preoperative floor or postoperative ceiling effect was defined with the threshold of 15% of patients reporting either the worst possible (0 for KOOSglobal and IKDC) or the best possible (100 for KOOSglobal and IKDC) scores, respectively. Results: The newly developed KOOSglobal was responsive after ACL reconstruction and demonstrated convergent validity with the IKDC. The KOOSglobal significantly correlated with the IKDC scores (ρ = 0.91, P < .001), explained 83% of the variability in IKDC scores, and was similarly responsive (relative efficiency = 0.63). While there was a higher rate of perfect postoperative scores with the KOOSglobal (213 of 1904, 11%) than with the IKDC (6%), the KOOSglobal was still below the 15% ceiling effect threshold. Conclusion: The large ceiling effects limit the ability to use several of the KOOS subscales with the younger, more active ACL population. However, by creating an aggregate score from the KOOS, JR and 4 KOOS Quality of Life subscale questions, the 11-item KOOSglobal offers a responsive PRO tool after ACL reconstruction that converges with the information captured with the IKDC. Also, by offering the ability to calculate multiple scores from a single questionnaire, the KOOSglobal may provide the orthopaedic community a single PRO platform to be used across knee-related subspecialties. Registration: NCT00478894 ( ClinicalTrials.gov identifier).

Background: Anterior cruciate ligament (ACL) reconstruction can effectively return athletes to the playing field, but they are still at risk of developing posttraumatic osteoarthritis (PTOA). No studies have used multivariable analysis to evaluate the predictors of radiographic PTOA in the lateral compartment of the knee at short-term follow-up after ACL reconstruction. Purpose: To determine the predictors of radiographic joint space narrowing in the lateral compartment 2 to 3 years after ACL reconstruction in a young, active cohort. Study Design: Cohort study; Level of evidence, 2. Methods: A nested cohort of 358 patients from the Multicenter Orthopaedic Outcomes Network (MOON) prospective cohort who were aged ≤33 years, were injured playing a sport, and had never undergone surgery on the contralateral knee were followed up 2 years after ACL reconstruction with questionnaires and with weightbearing knee radiographs using the metatarsophalangeal (MTP) joint technique. The joint space width in the lateral compartment was measured using a semiautomatic computerized method, and multivariable predictive modeling was used to evaluate the relationship between meniscus treatment, cartilage injury, graft type, and joint space while adjusting for age, sex, body mass index, and Marx activity score. Results: The mean lateral joint space width was 0.11 mm narrower on the ACL-reconstructed knee compared with the contralateral healthy knee (7.69 mm vs 7.80 mm, respectively; P < .01). Statistically significant predictors of a narrower joint space width on the ACL-reconstructed knee included lateral meniscectomy ( P < .001) and a Marx activity score less than 16 points ( P < .001). Conclusion: This study identifies lateral meniscectomy and a lower baseline Marx activity score to be predictors of radiographic joint space narrowing in the lateral compartment 2 to 3 years after ACL reconstruction in young, active patients without a prior knee injury.

Objectives: Articular cartilage and meniscal damage are commonly encountered and often treated at the time of anterior cruciate ligament reconstruction (ACLR). Our understanding of how these injuries and their treatment relate to outcomes of ACLR is still evolving. The purpose of this study was to assess whether articular cartilage and meniscal variables are predictive of 10-year outcomes after ACLR. We hypothesized that articular cartilage lesions and meniscus tears/treatment would be predictors of the IKDC, KOOS (all 5 subscales), and Marx activity level at 10-year follow-up after ACLR. Methods: Between 2002 and 2008, 3273 ACLR subjects were prospectively enrolled and followed longitudinally with the IKDC, KOOS, and Marx activity score completed at entry, 2, 6, and 10 years. A logistic regression model was built incorporating variables from patient demographics, surgical technique, articular cartilage injuries, and meniscus tears/treatment to determine the risk factors of IKDC, KOOS, and Marx at 10 years. Results: We completed a minimum follow-up on 77% (2530/3273) of our cohort at 10 years. The cohort was 56% male with a median age of 23 years at the time of enrollment. Incidence of concomitant pathology at the time of surgery consisted of the following: articular cartilage (medial femoral condyle [MFC]-22%, lateral femoral condyle [LFC]-15%, medial tibial plateau [MTP]-4%, lateral tibial plateau [LTP]-11%, patella-18%, trochlear-8%) and meniscal (medial-37%, lateral-46%). Variables that were predictive of 10-year outcomes included articular cartilage damage in the patellofemoral and medial compartments and previous medial meniscus surgery (6% of knees) (Table). Medial and lateral meniscus tears and treatment at the time of ACLR were not associated with 10-year outcomes. Other variables that significantly influenced 10-year outcomes included sex, race, BMI, type of reconstruction (primary vs. revision), baseline outcome scores, and MCL pathology (5.5% of knees). Conclusions: Articular cartilage injury in the patellofemoral and medial compartments at the time of ACLR and a history of medial meniscus surgery prior to ACLR are associated with 10-year ACLR outcomes. However, meniscal tears/treatment at the time of ACLR did not predict 10-year outcomes.

Background:When meniscal repair is performed during anterior cruciate ligament (ACL) reconstruction (ACLR), the effect of ACL graft type on meniscal repair outcomes is unclear.Hypothesis:The authors hypothesized that meniscal repairs would fail at the lowest rate when concomitant ACLR was performed with bone--patellar tendon--bone (BTB) autograft.Study Design:Cohort study; Level of evidence, 3.Methods:Patients who underwent meniscal repair at primary ACLR were identified from a longitudinal, prospective cohort. Meniscal repair failures, defined as any subsequent surgical procedure addressing the meniscus, were identified. A logistic regression model was built to assess the association of graft type, patient-specific factors, baseline Marx activity rating score, and meniscal repair location (medial or lateral) with repair failure at 6-year follow-up.Results:A total of 646 patients were included. Grafts used included BTB autograft (55.7%), soft tissue autograft (33.9%), and various allografts (10.4%). We identified 101 patients (15.6%) with a documented meniscal repair failure. Failure occurred in 74 of 420 (17.6%) isolated medial meniscal repairs, 15 of 187 (8%) isolated lateral meniscal repairs, and 12 of 39 (30.7%) of combined medial and lateral meniscal repairs. Meniscal repair failure occurred in 13.9% of patients with BTB autografts, 17.4% of patients with soft tissue autografts, and 19.4% of patients with allografts. The odds of failure within 6 years of index surgery were increased more than 2-fold with allograft versus BTB autograft (odds ratio = 2.34 [95% confidence interval, 1.12-4.92]; P = .02). There was a trend toward increased meniscal repair failures with soft tissue versus BTB autografts (odds ratio = 1.41 [95% confidence interval, 0.87-2.30]; P = .17). The odds of failure were 68% higher with medial versus lateral repairs ( P < .001). There was a significant relationship between baseline Marx activity level and the risk of subsequent meniscal repair failure; patients with either very low (0-1 points) or very high (15-16 points) baseline activity levels were at the highest risk ( P = .004).Conclusion:Meniscal repair location (medial vs lateral) and baseline activity level were the main drivers of meniscal repair outcomes. Graft type was ranked third, demonstrating that meniscal repairs performed with allograft were 2.3 times more likely to fail compared with BTB autograft. There was no significant difference in failure rates between BTB versus soft tissue autografts.Registration:NCT00463099 (ClinicalTrials.gov identifier).

Background:Articular cartilage health is an important issue following anterior cruciate ligament (ACL) injury and primary ACL reconstruction. Factors present at the time of primary ACL reconstruction may influence the subsequent progression of articular cartilage damage.Hypothesis:Larger meniscus resection at primary ACL reconstruction, increased patient age, and increased body mass index (BMI) are associated with increased odds of worsened articular cartilage damage at the time of revision ACL reconstruction.Study Design:Case-control study; Level of evidence, 3.Methods:Subjects who had primary and revision data in the databases of the Multicenter Orthopaedics Outcomes Network (MOON) and Multicenter ACL Revision Study (MARS) were included. Reviewed data included chondral surface status at the time of primary and revision surgery, meniscus status at the time of primary reconstruction, primary reconstruction graft type, time from primary to revision ACL surgery, as well as demographics and Marx activity score at the time of revision. Significant progression of articular cartilage damage was defined in each compartment according to progression on the modified Outerbridge scale (increase ≥1 grade) or >25% enlargement in any area of damage. Logistic regression identified predictors of significant chondral surface change in each compartment from primary to revision surgery.Results:A total of 134 patients were included, with a median age of 19.5 years at revision surgery. Progression of articular cartilage damage was noted in 34 patients (25.4%) in the lateral compartment, 32 (23.9%) in the medial compartment, and 31 (23.1%) in the patellofemoral compartment. For the lateral compartment, patients who had >33% of the lateral meniscus excised at primary reconstruction had 16.9-times greater odds of progression of articular cartilage injury than those with an intact lateral meniscus ( P < .001). For the medial compartment, patients who had Conclusion:Excision of the medial and lateral meniscus at primary ACL reconstruction increases the odds of articular cartilage damage in the corresponding compartment at the time of revision ACL reconstruction. Increased age is a risk factor for deterioration of articular cartilage in both tibiofemoral compartments, while increased BMI and the use of allograft for primary ACL reconstruction are associated with an increased risk of progression in the patellofemoral compartment.

Background:Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly good and are worse among young female athletes. Developing better rehabilitation and return-to-sport training programs and evaluating their outcomes are essential.Purpose:(1) Test the effect of strength, agility, plyometric, and secondary prevention (SAPP) exercises with and without perturbation training (SAPP + PERT) on strength, hops, function, activity levels, and return-to-sport rates in young female athletes 1 and 2 years after ACLR and (2) compare 2-year functional outcomes and activity levels among young female athletes in the Anterior Cruciate Ligament Specialized Post-Operative Return-to-Sports (ACL-SPORTS) trial to homogeneous cohorts who completed criterion-based postoperative rehabilitation alone (Multicenter Orthopaedic Outcomes Network [MOON]) and in combination with extended preoperative rehabilitation (Delaware-Oslo).Study Design:Randomized controlled trial, Level of evidence, 1; and cohort study, Level of evidence, 3.Methods:A total of 40 level 1 and level 2 female athletes were enrolled after postoperative impairment resolution 3 to 9 months after primary ACLR. Participants were randomized to 10 SAPP or SAPP + PERT sessions and were tested 1 and 2 years after ACLR on quadriceps strength, hop tests, functional outcomes, and return-to-sport rates. Participants were then compared with homogeneous cohorts of young (Results:No significant or meaningful differences were found between SAPP and SAPP + PERT, so groups were collapsed for comparison with the other cohorts. At 2-year follow-up, ACL-SPORTS had the highest scores ( P < .01) on the Marx activity rating scale (ACL-SPORTS, 13.5 ± 3.3; Delaware-Oslo, 12.5 ± 2.7; MOON, 10.6 ± 5.1); International Knee Documentation Committee Subjective Knee Evaluation Form (96 ± 7, 92 ± 9, and 84 ± 14, respectively); and Knee injury and Osteoarthritis Outcome Score (KOOS) subscales for Pain (98 ± 4, 94 ± 9, and 90 ± 10, respectively), Symptoms (94 ± 6, 90 ± 9, and 83 ± 14, respectively), Activities of Daily Living (100 ± 1, 99 ± 4, and 96 ± 7, respectively), Sports and Recreation (94 ± 8, 86 ± 15, and 82 ± 17, respectively), and Quality of Life (89 ± 14, 78 ± 18, and 76 ± 19, respectively). The Patient Acceptable Symptom State threshold on the KOOS–Sports and Recreation was achieved by 100% of the ACL-SPORTS cohort compared with 90% of Delaware-Oslo and 78% of MOON ( P = .011).Conclusion:Although perturbation training provided no added benefit, 10 sessions of return-to-sport training, compared with criterion-based postoperative rehabilitation alone, yielded statistically significant and clinically meaningfully higher 2-year functional outcomes among young, high-level female athletes after ACLR.Registration:NCT01773317 ( ClinicalTrials.gov identifier).

Background: Injuries to the posterolateral corner (PLC) may occur concurrently with anterior cruciate ligament (ACL) injury. Purpose/Hypothesis: This study evaluated the outcomes of patients who underwent operative management of PLC injuries concurrently with ACL reconstruction in a prospective multicenter cohort. We hypothesized that there would be no differences in outcomes between patients who were treated with PLC repair and PLC reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing ACL reconstruction were enrolled into a prospective longitudinal multicenter cohort between 2002 and 2008. Those with complete 6-year follow-up data (patient-reported outcomes and subsequent surgery information) were identified. Excluded from the study were patients with posterior cruciate ligament injuries. Patients who underwent PLC repair were compared with those who underwent PLC reconstruction with regard to interval from injury to surgery, need for revision surgery, and long-term outcomes at 6 years. Results: During the identified time frame, 3026 identified patients underwent primary ACL reconstruction; 34 (1.1%) also underwent concurrent PLC surgery (15 repairs, 19 reconstructions [18 allografts, 1 autograft]). With the numbers available, we did not detect significant differences between groups regarding the rate of meniscal or chondral injuries. Median time to PLC reconstruction was 121 days as compared with 19 days for concurrent ACL reconstruction and PLC repair ( P = .01). There were no between-group differences in Marx activity scores prior to surgery ( P = .4). At 6-year follow-up, there were no between-group differences in Knee injury and Osteoarthritis Outcome Score ( P = .36-.83) or International Knee Documentation Committee score ( P = .84); however, patients treated with PLC reconstructions had lower Marx activity scores (4.1 vs 9.4; P = .02). There was 1 ACL revision in the PLC reconstruction group, and 1 of the PLC repairs was revised to a reconstruction during the follow-up period. Conclusion: Good outcomes were achieved at 6-year follow-up with both repair and reconstruction of PLC injuries treated concurrently with ACL reconstruction. The PLC reconstruction group had lower activity levels 6 years after surgery. The present data suggest that, for appropriately selected patients undergoing acute surgical treatment of combined ACL and PLC injuries, PCL repair can achieve good long-term outcomes.

Background: The prevalence of patellofemoral joint (PFJ) osteoarthritis ranges from 8% to 47% at 7 to 10 years after anterior cruciate ligament reconstruction (ACLR) using bone–patellar tendon–bone (BTB) autograft. In performing BTB ACLR, some hypothesize that either trauma caused by harvest of the BTB autograft or altered biomechanics contributes to PFJ posttraumatic osteoarthritis. Purpose/Hypothesis: To determine whether knees with ACLR using a BTB autograft show early signs of posttraumatic osteoarthritis as compared with the contralateral uninjured knee 2 years after ACLR. We hypothesized that a BTB autograft will not increase the prevalence of PFJ osteoarthritis. Study Design: Cohort study; Level of evidence, 3. Methods: Bilateral knee 3-T magnetic resonance imaging (MRI) scans were collected in 57 patients (mean age, 20.3 years; 28 men) from a single site at a minimum of 2 years after ACLR. Structural MRI assessment of the knees was performed using the MRI Osteoarthritis Knee Score semiquantitative scoring system by a board-certified musculoskeletal radiologist. The presence of cartilage defects in the patellofemoral compartment was compared between the reconstructed and contralateral uninjured knees using logistic regression analyses. Results: There were no significant differences in the prevalence of cartilage defects (full thickness or any thickness) in the PFJ between the BTB ACLR knees and the contralateral control knees: 38.6% of BTB ACLR knees had PFJ cartilage defects versus 31.6% of contralateral control knees ( P > .391). The 95% CI for the difference between these groups was –9.0% to 23.0%. Conclusion: When comparing BTB ACLR knees with the uninjured contralateral knees in the study patients, we failed to observe statistically significant differences in the prevalence of PFJ cartilage lesions of full thickness or any thickness. These results should be used in shared decision-making with athletes when choosing the appropriate autograft during reconstruction. Our wide 95% CIs secondary to a smaller sample size demonstrate a need for larger studies in this area to more accurately describe the difference between the operative and contralateral knees.

Background:It is increasingly recognized that biochemical abnormalities of the joint precede radiographic abnormalities of posttraumatic osteoarthritis (PTOA) by as much as decades. A growing body of evidence strongly suggests that the progression from anterior cruciate ligament (ACL) injury to PTOA is multifactorial, involving the interplay between biomechanical disturbances and biochemical homeostasis of articular cartilage.Purpose:The purposes of this randomized study using an acute ACL injury model were to (1) evaluate the natural progression of inflammatory and chondrodegenerative biomarkers, (2) evaluate the relationship between subjective reports of pain and inflammatory and chondrodegenerative biomarkers, and (3) determine if postinjury arthrocentesis and corticosteroid injection offer the ability to alter this biochemical cascade.Study Design:Randomized controlled trial; Level of evidence, 2.Methods:A total of 49 patients were randomized to 4 groups: group 1 (corticosteroid at 4 days after ACL injury, placebo injection of saline at 2 weeks), group 2 (placebo at 4 days after ACL injury, corticosteroid at 2 weeks), group 3 (corticosteroid at both time intervals), or a placebo group (saline injections at both time intervals). Patient-reported outcome measures and synovial biomarkers were collected at approximately 4 days, 11 days, and 5 weeks after injury. The change between the time points was assessed for all variables using Wilcoxon tests, and the relationship between changes in outcome scores and biomarkers were assessed by calculating Spearman ρ. Outcomes and biomarkers were also compared between the 4 groups using Kruskal-Wallis tests.Results:No adverse events or infections were observed in any study patients. With the exception of matrix metalloproteinase 1 (MMP-1) and tumor necrosis factor–inducible gene 6 (TSG-6), chondrodegenerative markers worsened over the first 5 weeks while all patient-reported outcomes improved during this time, regardless of treatment group. Patient-reported outcomes did not differ between patients receiving corticosteroid injections and the placebo group. However, increases in C-telopeptide of type II collagen (CTX-II), associated with collagen type II breakdown, were significantly greater in the placebo group (1.32 ± 1.10 ng/mL) than in either of the groups that received the corticosteroid injection within the first several days after injury (group 1: 0.23 ± 0.27 ng/mL [ P = .01]; group 3: 0.19 ± 0.34 ng/mL [ P = .01]).Conclusion:PTOA begins at the time of injury and results early on in dramatic matrix changes in the knee. However, it is encouraging that early intervention with an anti-inflammatory agent was able to affect biomarkers of chondral degeneration. Should early intervention lead to meaningful changes in either the onset or severity of symptomatic PTOA, the current treatment paradigm for patients with ACL injury may have to be restructured to include early aspiration and intra-articular intervention.Trial Registration:ClinicalTrials.gov identifier: NCT01692756.

Background:Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions.Purpose/Hypothesis:The purpose of this study was to determine if the prevalence, location, and/or degree of meniscal and chondral damage noted at the time of revision ACL reconstruction predicts activity level, sports function, and osteoarthritis symptoms at 2-year follow-up. The hypothesis was that meniscal loss and high-grade chondral damage noted at the time of revision ACL reconstruction will result in lower activity levels, decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery.Study Design:Cohort study; Level of evidence, 2.Methods:Between 2006 and 2011, a total of 1205 patients who underwent revision ACL reconstruction by 83 surgeons at 52 hospitals were accumulated for study of the relationship of meniscal and articular cartilage damage to outcome. Baseline demographic and intraoperative data, including the International Knee Documentation Committee (IKDC) subjective knee evaluation, Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Marx activity score, were collected initially and at 2-year follow-up to test the hypothesis. Regression analysis was used to control for age, sex, body mass index, smoking status, activity level, baseline outcome scores, revision number, time since last ACL reconstruction, incidence of having a previous ACL reconstruction on the contralateral knee, previous and current meniscal and articular cartilage injury, graft choice, and surgeon years of experience to assess the meniscal and articular cartilage risk factors for clinical outcomes 2 years after revision ACL reconstruction.Results:At 2-year follow-up, 82% (989/1205) of the patients returned their questionnaires. It was found that previous meniscal injury and current articular cartilage damage were associated with the poorest outcomes, with prior lateral meniscectomy and current grade 3 to 4 trochlear articular cartilage changes having the worst outcome scores. Activity levels at 2 years were not affected by meniscal or articular cartilage pathologic changes.Conclusion:Prior lateral meniscectomy and current grade 3 to 4 changes of the trochlea were associated with worse outcomes in terms of decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery, but they had no effect on activity levels.Registration:NCT00625885

Objectives: Subsequent surgeries after ACL reconstruction are known to negatively affect patient satisfaction and outcomes. Previous studies have identified risk factors for subsequent operations after ACL reconstruction, but few studies have identified factors which increase the risk for subsequent specific procedures related to meniscus and articular cartilage.The purpose of this study was two-fold: 1) to report the incidence and types of subsequent surgeries which occur in a cohort of ACL reconstructed patients 6 years following their index ACL reconstruction; and, 2) to predict which variables (i.e. patient demographic and surgical) may influence the incidence of a patient having a subsequent meniscus or articular cartilage related surgery following their index ACL reconstruction. Methods: This was a multicenter longitudinal prospective cohort study design. Each participant completed a questionnaire that included baseline demographics, injury descriptors, sports participation level, comorbidities, knee surgical history, and validated patient-reported outcome measures, and were followed up at 2 and 6 years. In addition, patients were also contacted to determine whether any underwent additional surgical knee procedures since baseline. Operative reports were obtained and independently read by two orthopaedic surgeons, and all procedures were categorized and recorded, along with the surgical date. If multiple procedures were done during an operation, all were recorded. Two separate logistical regression models were constructed to predict which independent variables (i.e. patient demographic and surgical) potentially influenced the incidence of a patient having a subsequent surgery following their index ACL reconstruction: model #1 examined subsequent meniscus-related surgeries on the ipsilateral knee and model #2 examined subsequent articular cartilage-related surgeries. Results: The cohort consisted of 3,276 subjects (56% male) with a median age of 23 years at the time of enrollment. Primary ACL reconstructions comprised 93% of the group, while 7% were enrolled as revision ACL reconstructions. The majority of subjects underwent bone-patellar tendon-bone (BTB) autograft reconstructions (43%), while 34% underwent hamstring autograft and 23% had allograft reconstructions. We obtained 92% (2999/3276) follow-up with regards to information on incidence and frequency of subsequent surgeries on the cohort. The remaining 8% (277/3276) were lost to follow-up. Overall, 20% (612/2999) of the cohort was documented to have had at least one subsequent surgery on the ipsilateral knee 6 years following their index ACL reconstruction. These 612 subjects encompassed 1,272 categorical procedures. The most common subsequent procedures on the ipsilateral knee were meniscus-related (n=357 procedures;11.9% of follow-up cohort), revision ACL reconstruction (226 procedures; 7.5% of cohort), arthrofibrosis-related (235 procedures; 7.8% of cohort), or articular cartilage-related (201 procedures; 6.7% of cohort). Collectively, subsequent procedures involving the medial meniscus (repairs and/or meniscectomies) occurred almost twice as frequently as the lateral meniscus (7.4% vs. 4.2%). Surprisingly, only 19 total knee arthroplasties (0.6% of cohort) were performed during this follow-up time period, at a median time of 45 months following the patient’s index ACL reconstruction. The variables that were found to be significant predictors of having a subsequent meniscal surgery on the ipsilateral knee were patients with lower age, higher baseline Marx activity level, patients who had quit smoking (compared to non-smokers), having a autograft hamstring or allograft (compared to an autograft BTB), or having a medial meniscus repair or a medial meniscus tear that was not treated at the time of index surgery. After adjusting for all other covariates, patients with an index medial meniscus repair were 4.4 times more likely to undergo a subsequent surgery related to the meniscus than patients with no initial medial meniscal pathology. The variables that were found to be significant predictors of having a subsequent surgery involving the articular cartilage (AC) were patients with higher BMI, higher baseline Marx activity level, having an autograft hamstring or allograft (compared to an autograft BTB), having a meniscus repair at the time of index surgery, or having Grade 3 or 4 AC pathology in any compartment. Specifically, if a patient has grade 4 changes in any compartment at the time of their index reconstruction, they are over 3 times more likely to have a subsequent AC-related surgery by 6 years, after controlling for all covariates (pConclusion: This study identified the incidence of subsequent surgeries and risk factors for having subsequent meniscus or articular cartilage related procedures over a 6-year follow up period. Identifying and understanding these risk factors is a critical step in helping to mitigate the risks to improve patient outcomes.

Background: The management of meniscus tears identified at the time of primary anterior cruciate ligament (ACL) reconstruction is highly variable and includes repair, meniscectomy, and nontreatment. Hypothesis/Purpose: The purpose of this study was to determine the reoperation rate for meniscus tears left untreated at the time of ACL reconstruction with a minimum follow-up of 6 years. The hypothesis was that small peripheral tears identified at the time of ACL reconstruction managed with “no treatment” would have successful clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Patients with meniscus tears left untreated at the time of primary ACL reconstruction were identified from a multicenter study group with a minimum 6-year follow-up. Patient, tear, and reoperation data were obtained for analysis. The need for reoperation was used as the primary endpoint, with analysis performed to determine patient and tear characteristics associated with reoperation. Results: There were 194 patients with 208 meniscus tears (71 medial, 137 lateral) left in situ without treatment with a complete follow-up for analysis. Of these, 97.8% of lateral and 94.4% of medial untreated tears required no reoperation. Sixteen tears (7.7%) left in situ without treatment underwent subsequent reoperation: 9 tears (4.3%) underwent reoperation in the setting of revision ACL reconstruction, and 7 tears (3.4%) underwent reoperation for an isolated meniscus injury. The patient age was significantly lower in patients requiring reoperation, while tears measuring ≥10 mm more frequently required reoperation. Conclusion: Lateral and medial meniscus tears left in situ at the time of ACL reconstruction did not require reoperation at a minimum 6-year follow-up for 97.8% and 94.4% of tears, respectively. These findings re-emphasize the low reoperation rate after the nontreatment of small, peripheral lateral meniscus tears while noting less predictable results for medial meniscus tears left without treatment.

Objectives: Injuries to the posterolateral corner (PLC) may occur concurrently with anterior cruciate ligament (ACL) injury. Restoration of stability to the lateral knee is important for both preventing posterolateral rotatory instability and protecting concurrently addressed cruciate reconstructions. There has been a growing trend towards PLC reconstruction in recent literature, however little is known about how these techniques relate to long-term patient outcomes. The purpose of the present study was to evaluate the outcomes of patients who underwent operative management of PLC injuries concurrently with ACL reconstruction in a prospective multicenter cohort. We hypothesized that there would be no differences in patient outcomes between patients who were treated with repair and reconstruction. Methods: Patients undergoing ACL reconstructions were enrolled into a prospective longitudinal multi-center cohort between 2002-2008. Patients with six-year follow-up data (repeat operations and patient reported outcomes) who underwent concurrent PLC reconstruction or repair at the time of ACL reconstruction were identified. Patients who underwent PLC repair were compared to those who underwent PLC reconstruction in regard to operative delay, need for revision surgery and long-term outcomes at 6-years. Results: Initially, 3028 patients were identified to have undergone primary ACL reconstruction during the identified time frame, with 34/3028 (1.1%) also undergoing PLC surgery: 15 repairs and 19 reconstructions (18 allografts, 1 autograft). There were no differences in the rate of meniscal or chondral injuries between groups. The median time to PLC reconstruction was 121 days compared to 19 days for concurrent ACL reconstruction and PLC repair (p=0.01). Mean preoperative scores were significantly lower in the repair group with respect to KOOS Pain (57.4 versus 74.3), KOOS ADL (62.3 versus 76.2), KOOS KRQOL (17.5 versus 30.9), and IKDC (29.1 versus 48.4, p=0.004). There were no differences between groups in Marx activity scores prior to surgery (p=0.4). At 6-year follow-up, there were no differences between groups with regard to KOOS (p=0.36-0.83) or IKDC scores (p=0.84), however patients treated with lateral reconstructions had lower Marx activity scores at 6-years (4.0 versus 9.4, p=0.02). There was one ACL revision in the PLC reconstruction group and one of the PLC repairs was revised to a reconstruction during the follow-up period. Conclusion: Good outcomes were achieved with both repair and reconstruction of PLC injuries treated concurrently with ACL reconstruction at 6-year follow-up. Patients treated with reconstruction had lower activity levels 6-years after surgery. Lower KOOS and IKDC scores at the time of surgery may be explained by the increased time interval between injury and surgery in the reconstruction group. One of the 15 lateral repairs required a later reconstruction. Contrary to recent reports, our data suggests that appropriately selected patients may be successfully treated with acute PLC repair with good long-term outcomes.

Objectives: Regardless of surgical or conservative management, the majority of patients develop posttraumatic osteoarthritis (PTOA) within 15 years of anterior cruciate ligament (ACL) injury. In addition to MRI or radiographic evidence of cartilage degeneration, the onset of PTOA is associated with increased concentrations of chondrodegenerative and inflammatory biomarkers and reduced Knee Injury and Osteoarthritis Score Quality of Life (KOOS-QOL) scores. Postoperatively, biochemical biomarkers may offer the ability to detect the onset of PTOA earlier than traditional imaging methods; however, little is known about the ability of preoperatively collected biomarkers to predict postoperative symptoms often associated with early onset of PTOA. The purpose of this prospective study was to determine if patient demographics and biomarkers collected on the day of ACL reconstruction could accurately explain the variability in postoperative KOOS-QOL scores. We hypothesized that no combination of biomarkers collected on the day of ACL reconstruction would be associated with 2-year patient-reported outcomes. Methods: Participants included 18 patients (9 females, 9 males; age = 20.1 ± 5.2 years; height = 177.7 ± 11.9 cm; weight = 77.8 ± 18.0 kg) that had previously enrolled in a prospective randomized trial evaluating early anti-inflammatory treatment after ACL injury. As part of the initial trial, synovial, serum, and urinary biomarkers of chondrodegeneration and inflammation were collected on the day of ACL reconstruction. Patients were then contacted to complete patient-reported outcomes 2 years following surgery. A linear regression was performed to determine if a model generated from patient demographics and biomarkers on the day of surgery and could accurately explain the variability in KOOS-QOL scores at 2 years. Results: KOOS-QOL scores significantly improved from 39.9 ± 14.2 on the day of ACL reconstruction to 66.7 ± 19.7 at 2 years (p < 0.001). A model containing urinary CTX-II and sex explained 52% of the variability in 2-year KOOS-QOL scores (adjusted R2 = 0.52, p = 0.002), with higher urinary CTX-II values and female sex associated with poorer KOOS-QOL scores. Urinary CTX-II, which is a biomarker of type II collagen breakdown, individually explained 32% of the variability in 2-year KOOS-QOL scores (p = 0.01) with sex explaining 20% of the variability (p = 0.02). Conclusion: Previous studies have demonstrated that ACL injury triggers a biochemical cascade that worsens over the first 4-6 weeks after injury. The current results demonstrated that higher levels of collagen breakdown as measured via CTX-II levels at the time of surgery was associated with worse KOOS-QOL outcomes at 2 years. This data strongly suggests that initial biochemical changes after injury may have powerful consequences for the injured knee that are not mitigated by surgical stabilization alone. Early anti-catabolic intervention after ACL injury may need to be investigated as an adjunct treatment strategy, particularly in female patients with high CTX-II levels.

Background: Most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome; however, graft choice for revision may be limited due to previously used grafts. Hypotheses: Autograft use would result in increased sports function, increased activity level, and decreased osteoarthritis symptoms (as measured by validated patient-reported outcome instruments). Autograft use would result in decreased graft failure and reoperation rate 2 years after revision ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons at 52 sites. Data collected included baseline demographics, surgical technique, pathologic abnormalities, and the results of a series of validated, patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Marx activity rating score). Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Incidences of additional surgery and reoperation due to graft failure were also recorded. Multivariate regression models were used to determine the predictors (risk factors) of IKDC, KOOS, WOMAC, Marx scores, graft rerupture, and reoperation rate at 2 years after revision surgery. Results: A total of 1205 patients (697 [58%] males) were enrolled. The median age was 26 years. In 88% of patients, this was their first revision, and 341 patients (28%) were undergoing revision by the surgeon who had performed the previous reconstruction. The median time since last ACL reconstruction was 3.4 years. Revision using an autograft was performed in 583 patients (48%), allograft was used in 590 (49%), and both types were used in 32 (3%). Questionnaire follow-up was obtained for 989 subjects (82%), while telephone follow-up was obtained for 1112 (92%). The IKDC, KOOS, and WOMAC scores (with the exception of the WOMAC stiffness subscale) all significantly improved at 2-year follow-up ( P < .001). In contrast, the 2-year Marx activity score demonstrated a significant decrease from the initial score at enrollment ( P < .001). Graft choice proved to be a significant predictor of 2-year IKDC scores ( P = .017). Specifically, the use of an autograft for revision reconstruction predicted improved score on the IKDC ( P = .045; odds ratio [OR] = 1.31; 95% CI, 1.01-1.70). The use of an autograft predicted an improved score on the KOOS sports and recreation subscale ( P = .037; OR = 1.33; 95% CI, 1.02-1.73). Use of an autograft also predicted improved scores on the KOOS quality of life subscale ( P = .031; OR = 1.33; 95% CI, 1.03-1.73). For the KOOS symptoms and KOOS activities of daily living subscales, graft choice did not predict outcome score. Graft choice was a significant predictor of 2-year Marx activity level scores ( P = .012). Graft rerupture was reported in 37 of 1112 patients (3.3%) by their 2-year follow-up: 24 allografts, 12 autografts, and 1 allograft and autograft. Use of an autograft for revision resulted in patients being 2.78 times less likely to sustain a subsequent graft rupture compared with allograft ( P = .047; 95% CI, 1.01-7.69). Conclusion: Improved sports function and patient-reported outcome measures are obtained when an autograft is used. Additionally, use of an autograft shows a decreased risk in graft rerupture at 2-year follow-up. No differences were noted in rerupture or patient-reported outcomes between soft tissue and bone–patellar tendon–bone grafts. Surgeon education regarding the findings of this study has the potential to improve the results of revision ACL reconstruction.

Background: Meniscal repair is commonly performed concurrently with anterior cruciate ligament reconstruction (ACLR) in the acutely injured knee. No large-scale, prospective multicenter studies have evaluated the long-term success and patient-oriented outcomes after combined ACLR and meniscal repair. Purpose: To define the operative success and patient-oriented outcome scores 6 years after combined meniscal repair and ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: All ipsilateral primary ACLR and meniscal repair cases from a multicenter study group between 2002 and 2004 were selected. Validated patient-oriented outcome instruments were completed at 3 time points: preoperatively and then 2 and 6 years after the index procedure. Subsequent ipsilateral knee reoperations were confirmed by operative reports to evaluate for the failure of meniscal repairs. Results: In total, 286 patients with 1440 primary ACLRs underwent concurrent meniscal repairs (298 meniscal repairs). Of these, 235 (82.2%) were available for follow-up at 6 years (154 medial, 72 lateral, and 9 both lateral and medial meniscal repairs). Repaired menisci most commonly involved the peripheral one third of the meniscus (84%); patterns were typically longitudinal (84%) or displaced bucket-handle (10%), with a mean length of 16.5 ± 5.8 mm. Overall, the meniscal repair failure rate was 14% (medial: 21/154; lateral: 10/72; both: 2/9) at 6 years. Medial repairs failed earlier than lateral repairs (2.1 vs 3.7 years, respectively; P = .01). Significant improvements in outcome scores were sustained at 6-year follow-up. No differences in the suture number or type were detected between repair failures and successes. The rate of meniscal reoperations was higher in patients who underwent repair compared with those who did not have an identified meniscal injury at the time of ACLR ( P < .01. Conclusion: Concurrent meniscal repair with ACLR is associated with failure rates approximating 14% at 6-year follow-up. Improvements in patient-oriented outcome scores were sustained at 6-year follow-up. Surgeons may expect good clinical outcomes 6 years after combined ACLR and meniscal repair.

Background: An initial anterior cruciate ligament (ACL) tear can be treated with surgical reconstruction or focused rehabilitation. The KANON (Knee Anterior cruciate ligament, NON-surgical versus surgical treatment) randomized controlled trial compared rehabilitation plus early ACL reconstruction (ACLR) to rehabilitation plus optional delayed ACLR and found no difference at 2 years by an intention-to-treat analysis of total Knee injury and Osteoarthritis Outcome Score (KOOS) results. Purpose: To compare the cost-effectiveness of early versus delayed ACLR. Study Design: Economic and decision analysis; Level of evidence, 2. Methods: A Markov decision model was constructed for a cost-utility analysis of early reconstruction (ER) versus rehabilitation plus optional delayed reconstruction (DR). Outcome probabilities and effectiveness were derived from 2 sources: the KANON study and the Multicenter Orthopaedic Outcomes Network (MOON) database. Collectively, these 2 sources provided data from 928 ACL-injured patients. Utilities were measured by the Short Form–6 dimensions (SF-6D). Costs were estimated from a societal perspective in 2012 US dollars. Costs and utilities were discounted in accordance with the United States Panel on Cost-Effectiveness in Health and Medicine. Effectiveness was expressed in quality-adjusted life-years (QALYs) gained. Principal outcome measures were average incremental costs, incremental effectiveness (as measured by QALYs), and net health benefits. Willingness to pay was set at $50,000, which is the currently accepted standard in the United States. Results: In the base case, the ER group resulted in an incremental gain of 0.28 QALYs over the DR group, with a corresponding lower overall cost to society of $1572. Effectiveness gains were driven by the low utility of an unstable knee and the lower utility for the DR group. The cost of rehabilitation and the rate of additional surgery drove the increased cost of the DR group. The most sensitive variable was the rate of knee instability after initial rehabilitation. When the rate of instability falls to 51.5%, DR is less costly, and when the rate of instability falls below 18.0%, DR becomes the preferred cost-effective strategy. Conclusion: An economic analysis of the timing of ACLR using data exclusively from the KANON trial, MOON cohort, and national average reimbursement revealed that early ACLR was more effective (improved QALYs) at a lower cost than rehabilitation plus optional delayed ACLR. Therefore, early ACLR should be the preferred treatment strategy from a societal health system perspective.

Background: Identifying risk factors for inferior outcomes after anterior cruciate ligament reconstruction (ACLR) is important for prognosis and future treatment. Hypothesis: Articular cartilage lesions and meniscus tears/treatment would predict International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS) (all 5 subscales), and Marx activity level at 6 years after ACLR. Study Design: Cohort study (prognosis); Level of evidence, 1. Methods: Between 2002 and 2004, a total of 1512 ACLR patients were prospectively enrolled and followed longitudinally, with the IKDC, KOOS, and Marx activity score completed at entry, 2 years, and 6 years. A logistic regression model was built incorporating variables from patient demographics, surgical technique, articular cartilage injuries, and meniscus tears/treatment to determine the predictors (risk factors) of IKDC and KOOS scores and Marx activity level at 6 years. Results: A minimum follow-up on 86% (1307/1512) of the cohort was completed at 6 years. The cohort was 56% male and had a median age of 23 years at the time of enrollment, with 76% reporting a noncontact injury mechanism. Incidence of concomitant injury at the time of surgery consisted of the following: articular cartilage (medial femoral condyle [MFC], 25%; lateral femoral condyle [LFC] 20%; medial tibial plateau [MTP], 6%; lateral tibial plateau [LTP], 12%; patella, 20%; trochlear, 9%) and meniscus (medial, 38%; lateral, 46%). Both articular cartilage lesions and meniscus tears were significant predictors of 6-year outcomes on the IKDC and KOOS. Grade 3 or 4 articular cartilage lesions (excluding patella) significantly reduced IKDC and KOOS scores at 6 years. The IKDC demonstrated worse outcomes with the presence of a grade 3 or 4 chondral lesion on the MFC, MTP, and LFC. Likewise, the KOOS score was negatively affected by cartilage injury. The sole significant predictor of reduced Marx activity level was the presence of a grade 4 lesion on the MFC. Lateral meniscus repairs did not correlate with inferior results, but medial meniscus repairs predicted worse IKDC and KOOS scores. Lateral meniscus tears left alone significantly improved prognosis. Small partial meniscectomies (50%) on either the medial or lateral menisci improved prognosis. Analogous to previous studies, other significant predictors of lower outcome scores were lower baseline scores, higher body mass index, lower education level, smoking, and anterior cruciate ligament revisions. Conclusion: Both articular cartilage injury and meniscus tears/treatment at the time of ACLR were significant predictors of IKDC and KOOS scores 6 years after ACLR. Similarly, having a grade 4 MFC lesion significantly reduced a patient’s Marx activity level score at 6 years.

Objectives: Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly acceptable and are worse among young female athletes. Developing better rehabilitation and return-to-sport (RTS) training programs and evaluating their outcomes are essential. The purposes of this study were to: 1) Test the effect of strength, agility, plyometric, and secondary prevention (SAPP) exercises with and without perturbation training (SAPP+PERT) on strength, hops, functional outcomes, activity levels, and RTS rates in young female athletes 1 and 2 years after ACLR; and 2) Compare 2-year functional outcomes and activity levels among young female athletes in the ACL-SPORTS trial to homogeneous cohorts who completed criterion-based post-operative rehabilitation alone (MOON) and in combination with extended pre-operative rehabilitation (DE-Oslo). We hypothesized that SAPP+PERT would result in superior outcomes compared to SAPP alone; and female athletes who structured completed post-operative RTS training, compared to those who did not, would have higher functional outcomes. Methods: Aim 1 is a randomized control trial (NCT01773317) while aim 2 is a cohort study. For aim 1, we enrolled 39 female athletes, based on power calculations described previously. Athletes were enrolled 3-9 months after primary ACLR when they achieved impairment resolution. Participants were randomized to 10 SAPP or SAPP+PERT sessions (˜2x/week) and tested 1 and 2 years after ACLR on quadriceps strength, 4 hop tests, functional outcome measures, and RTS rates. We used 2x2 mixed-model ANOVA to test aim 1 (α = 0.05). Secondary to no group differences, we collapsed across SAPP and SAPP+PERT for aim 2. We applied inclusion/exclusion criteria and constrained sex (female) and age (13 to < 25 years) to compare these athletes who received post-operative RTS training (ACL-SPORTS) to homogeneous subsets who completed criterion-based post-operative rehabilitation alone (MOON) and combined with extended pre-operative rehabilitation (DE-Oslo) on 2-yr outcomes: the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Marx Activity Rating Scale. We tested aim 2 using 3-way ANOVA and Chi-Square test of proportions to compare the proportion of individuals in each group who met the Patient Acceptable Symptom State (PASS) thresholds. Results: There were no significant or clinically meaningful differences between SAPP and SAPP+PERT; groups were collapsed for comparison to the other cohorts. ACL-SPORTS had the highest scores on every outcome (Table 1). A higher proportion of ACL-SPORTS achieved the PASS thresholds for the IKDC, KOOS Activities of Daily Living, and KOOS Sport and Recreation (Fig 1, p ≤ .01). Conclusion: Our 1st hypothesis, that the addition of perturbation training would result in superior clinical and functional outcomes, was not supported. Our 2nd hypothesis, that a structured RTS training program would improve outcomes over existing cohorts, was supported. Post-operative RTS training incorporating strengthening, agilities, and plyometrics but not necessarily perturbation training, may improve functional outcomes and activity levels among young female athletes after ACLR. We provide a prototype for RTS training that would be feasible to implement into group or non-clinical environments. Future RCTs should assess the comparative effectiveness of RTS training in various settings. [Table: see text][Figure: see text][Figure: see text][Figure: see text]

Objectives: The success rate of meniscal repair is known to increase with concurrent anterior cruciate ligament (ACL) reconstruction. However, the influence of ACL graft choice has not been described. The current study examines the effect of ACL graft choice on the outcome of meniscal repair performed in conjunction with ACL reconstruction (ACLR). Methods: Patients who underwent meniscal repair with concurrent primary ACLR were identified from a longitudinal, prospective cohort. Patient demographics and subjective outcome measures including the International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), and Marx activity rating scale were collected preoperatively. Arthroscopic assessment of meniscal tear characteristics and associated repair technique were recorded intraoperatively. Patients with subsequent repair failure, defined as any subsequent surgical procedure addressing the meniscus repaired at index surgery, were identified and operative notes were obtained in order to accurately classify pathology and treatment. A logistic regression model was built to assess the association of patient specific factors, ACL graft, baseline Marx activity level and meniscal tear laterality with the occurrence of repair failure at 6-year follow-up. Results: A total of 646 patients underwent ACLR with concurrent meniscal repair. Bone-patellar tendon-bone (BTB) and soft tissue (ST) autograft were used in 55.7% and 33.9% of cases, respectively, while allografts were utilized in the remaining cases. Table 1 summarizes the univariate analysis of each baseline variable. A total of 101 patients (15.6%) required subsequent surgery on the meniscus repaired at index surgery, including 89 meniscectomies (87 partial, 2 subtotal), 11 revision meniscal repairs, and 1 meniscus allograft transplantation. No statistically significant difference in meniscal repair failure rate was observed based on patient age, sex, BMI or smoking status. The odds of meniscal repair failure within 6 years of surgery for patients with only a lateral meniscal repair are 68% less than those with only a medial meniscal repair (CI: 41%, 83%; pConclusion: In the setting of primary ACLR, the risk of meniscal repair failure is increased with medial versus lateral meniscal repair. Patients with low or high baseline activity levels are also at an increased risk. ACL graft choice seems to have an effect on meniscal repair failure that approaches but does not reach statistical significance. A larger sample size may be required to accept the null hypothesis. [Table: see text][Figure: see text]

Objectives: Physicians’ and patients’ decision-making process between bone-patellar tendon-bone (BTB) versus hamstring autografts for ACL reconstruction (ACLR) may be influenced by a patient’s gender, laxity level, sport played, and/or competition level in the young, active athlete. The purpose of this study was to determine the incidence of subsequent ligament disruption for high school and college-aged athletes between autograft BTB versus hamstring grafts for ACLRs. Our hypothesis is there would be no recurrent ligament failure differences between autograft types at 6-year follow-up. Methods: Our inclusion criteria were patients aged 14-22 who were injured in sport (basketball, football, soccer, other), had a contralateral normal knee, and were due to have a unilateral primary ACLR with either a BTB or hamstring autograft. All patients were prospectively followed at two and six years and contacted by phone and/or email to determine whether any subsequent surgery had occurred to either knee since their initial ACLR. If so, operative reports were obtained, whenever possible, in order to document pathology and treatment. Multivariable regression modeling controlled for age, gender, ethnicity/race, body mass index, sport and competition level, activity level, knee laxity, and graft type. The six-year outcomes of interest were the incidence of subsequent ACL reconstruction to either knee. Results: Eight hundred thirty-nine (839) patients were eligible, of which 770 (92%) had 6-year follow-up for subsequent surgery outcomes. The median age was 17, with 48% females, and the distribution of BTB to hamstring was 492 (64%) and 278 (36%) respectively. Thirty-three percent (33%) of the cohort was classified as having “high grade” knee laxity preoperatively. The overall ACL revision rate was 9.2% in the ipsilateral knee, 11.2% in the contralateral normal ACL, and 19.7% had one or the other within 6 years of the index ACLR surgery. High-grade laxity (OR: 2.4; 95% CI: 1.4, 3.9; p=0.001), autograft type (OR: 2.1; 95% CI: 1.3, 3.5; p=0.004), and age (OR: 0.8; 95% CI: 0.7, 0.96; p=0.009) were the 3 most influential predictors of a recurrent ACL graft revision on the ipsilateral knee, respectively, whereas the sport of the index injury (OR: 0.3; 95% CI: 0.2, 0.7; p=0.002) was the most influential predictor of a subsequent primary ACL reconstruction on the contralateral knee. The odds of a recurrent ACL graft revision on the ipsilateral knee for patients receiving a hamstring autograft were 2.1 times the odds of a patient receiving a BTB autograft (95% CI: 1.3, 3.5). For low-risk patients (5% incidence of graft failure), a hamstring graft can increase the risk of recurrent ACL graft revision by 5 percentage points, from 5% to 10%. For high-risk patients (35% incidence of graft failure), a hamstring graft can increase the risk of recurrent ACL graft revision by 15 percentage points, from 35% to ˜ 50%. An individual prediction risk calculator for a subsequent ACL graft revision can be determined by the nomogram in Figure 1. Conclusion: There is a high rate of subsequent ACL tears in both the ipsilateral and contralateral knees in this young athletic cohort, with evidence suggesting that incidence of ACL graft revisions at 6 years following index surgery is significantly higher in hamstring autograft compared to BTB autograft. [Figure: see text]

Objectives: Multiple studies have shown patients are susceptible to post-traumatic osteoarthritis (PTOA) after anterior cruciate ligament (ACL) injury even with ACL reconstruction (ACLR). Prospective studies using multivariate analysis to identify risk factors for PTOA are lacking. This study aims to identify baseline predictors of radiographic PT OA after ACLR at an early time point and hypothesizes that meniscal injury and cartilage lesions will be associated with worse radiographic OA using the Osteoarthritis Research Society International (OARSI) atlas criteria. Methods: 421 patients who underwent ACLR returned onsite for standardized posteroanterior metatarsophalangeal radiographs a minimum of 2 years after surgery. At baseline, demographics, graft type, meniscal status/treatment, and cartilage status were collected. OARSI atlas criteria were used to grade all knee radiographs. Multivariable ordinal regression models identified baseline predictors of radiographic OARSI grades at follow-up. Results: The mean age was 19.8 years with 51.3% females. Higher age (odds ratio (OR) 1.06) and BMI (OR 1.05) were statistically significantly associated with higher OARSI grade in the medial compartment. Patients with a meniscal repair and a partial meniscectomy had statistically significantly higher OARSI grades in the medial compartment (meniscal repair OR 1.92 and meniscectomy OR 2.11) and in the lateral compartment (meniscal repair OR 1.96 and meniscectomy OR 2.97). Graft type, cartilage lesion, sex, and Marx activity scales had no significant association with OARSI grade. Conclusion: Older patients with a higher BMI who have an ACL tear with concurrent meniscal tear requiring partial meniscectomy or meniscal repair should be advised of their increased risk of developing radiographic OA. Alternatively, patients with an ACL tear with an articular cartilage lesion can be reassured that they are not at increased risk of developing radiographic knee OA at 2-3 years following ACLR.

Objectives: We present the early results from the “Multicenter Orthopaedic Outcome Network Early Anti-inflammatory Treatment in Patients with Acute ACL Tear and Painful Effusions” (MOON-AAA) clinical trial (figure 1). This trial allows for a well controlled prospective cohort of patients with isolated ACL injury at risk for OA. We compared the effect of a single versus a repeated dosage of Kenalog within the first two weeks after ACL injury and its effect on chondral degradation in the first 4 weeks prior to surgical reconstruction of the ACL. Methods: 49 patients with isolated ACL tears were enrolled. Knee joints were aspirated and patients received an injection with 40 mg Kenalog either within 4 days, 10 days, both time points or not at all (saline injection control). Serum, synovial fluid and urine were collected at 3 time points. Permutated block randomization, triple blinding, independent monitoring and standardized x-ray was performed to comply with GCP standards. Patient reported outcomes were collected at 6 time points up to 6 months post-ACL reconstruction(IKDC, KOOS and Marx activity level). A standardized synovial fluid biomarker panel was analyzed according to OARSI guidelines. Statistical analysis were performed using SAS mixed models analysis. Results: Serum analysis shows significant change after injury. Chondrodegradatory markers such as CTX-II, MMP-1 and MMP-3 as well as COMP indicate a progressive destruction of chondral matrix and collagen breakdown . There is a dramatic (250%) increase of CTX-II in the first 4 weeks. Matrix proteins such as MMP-1 and 3 as well as COMP show an initial increase and then a steep decline (see figure 1). Inflammatory markers (IL-1 alpha, IL-1beta, IRAP) show a decline from the time of injury. IL-1 alpha, however shows a dramatic uptake after week 2. This longitudinal data confirms a dramatic onset of early osteoarthritic biomarker profiles immediately after ACL injury as measured in synovial fluid.The administration of 40 mg of Kenalog significantly changes this dynamic. CTX-II shows a dramatic reduction and stays close to baseline levels over the course of 4 weeks pre-operatively. COMP and MMP-1 show a significantly lesser decline.There is no significant difference in the effect of Kenalog if given within 4 days of injury or within 2 weeks. There is a statistical trend indicating that a repeated dose of Kenalog may be more efficient in normalizing the biomarker levels. No AE’s, infections were observed. Two of 49 patients suffered a retear at 6 months upon return to activities. Conclusion: Our data show that posttraumatic osteoarthritis begins at the time of injury and results early on in dramatic matrix changes in the knee joint. An early intervention with an antiinflammatory agent, such as Kenalog, maybe be able to prevent some of these changes observed.We do not currently know if the early intervention results in meaningful clinical differences in overall outcome. Further follow-up will answer this question. However, it is encouraging that a simple early intervention is able to affect early chondral degeneration. Should the early intervention with Kenalog lead to meaningful changes in outcome at 2 or 6 years the current treatment paradigm for ACL injured patients may have to be changed.

Objective To determine (1) if bone bruise characteristics seen on magnetic resonance imaging are associated with patient-reported outcomes prior to and following anterior cruciate ligament reconstruction and (2) if the combined presence of bone bruises with articular cartilage pathology results in inferior 2- or 6-year outcomes. Design Bone bruise volume and severity were measured on 81 patients’ preoperative magnetic resonance imaging in the medial and lateral femoral condyle (MFC, LFC) and medial and lateral tibial plateau (MTP, LTP) using the Costa-Paz classification and a modified version of Roemer and Bohndorf’s technique. The relationships between bone bruise volume and severity with Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) scores were assessed, and pre- and postoperative KOOS and IKDC scores were compared between those with bone bruises either with or without combined local articular cartilage pathology. Results All 81 patients had a bone bruise in at least 1 region and 70 (86%) had bone bruises in ≥2 regions. LTP bruises were the most common (76/81, 94%), followed by the LFC (66, 81%), MTP (46, 57%), and MFC (20, 25%). Neither bone bruise volume nor severity was associated with inferior postoperative outcomes. The subset of 17 patients with bone bruises and combined articular cartilage pathology were 3.4 times more likely to be symptomatic at 6-year follow-up than those without articular cartilage pathology ( P = 0.04). Conclusions The volume and severity of preoperative bone bruises alone were not associated with 2- or 6-year outcomes; however, bone bruises combined with local articular cartilage pathology appear to be more symptomatic after ACL reconstruction.

Background: The predictors of anterior cruciate ligament reconstruction (ACLR) outcome at 6 years as measured by validated patient-based outcome instruments are unknown. Hypothesis: Certain variables evaluated at the time of ACLR will predict return to sports function (as measured by the International Knee Documentation Committee [IKDC] questionnaire and the Knee injury and Osteoarthritis Outcome Score [KOOS] Sports and Recreation subscale), knee-related quality of life (KOOS Knee Related Quality of Life subscale), and activity level (Marx Activity Scale). Potential predictor variables include demographic factors, surgical technique and graft choice for ACLR, and intra-articular injuries and treatment. Study Design: Cohort study; Level of evidence, 2. Methods: All patients with unilateral ACLRs from 2002 currently enrolled in the MOON (Multicenter Orthopaedic Outcomes Network) cohort were evaluated. Patients completed the validated outcome instruments preoperatively. Physicians documented intra-articular pathologic abnormalities, treatment, and surgical techniques used at the time of surgery. At 2 and 6 years postoperatively, patients completed the same validated outcome instruments. Results: Follow-up was obtained at 2 years (88%) and at 6 years (84%). The cohort was 57% male with a median age of 23 years at enrollment. The ability to perform sports function was maintained at 6 years, but the Marx activity level continued to decline from baseline. Revision ACLR and use of allograft predicted worse outcomes on the IKDC and both KOOS subscales. Lateral meniscus treatment, smoking status, and body mass index at baseline were each predictors on 2 of 3 scales. The predictors of lower activity level were revision ACLR and female sex. Conclusion: Six years after ACLR, patients could perform sports-related functions and maintain a high knee-related quality of life similar to their 2-year level, although their physical activity level (Marx) dropped over time. Choosing autograft rather than allograft, not smoking, and having normal body mass index are advised to improve long-term outcomes.

Background Revision anterior cruciate ligament (ACL) reconstruction has worse outcomes than primary reconstructions. Predictors for these worse outcomes are not known. The Multicenter ACL Revision Study (MARS) Group was developed to perform a multisurgeon, multicenter prospective longitudinal study to obtain sufficient subjects to allow multivariable analysis to determine predictors of clinical outcome. Purpose To describe the formation of MARS and provide descriptive analysis of patient demographics and clinical features for the initial 460 enrolled patients to date in this prospective cohort. Study Design Cross-sectional study; Level of evidence, 2. Methods After training and institutional review board approval, surgeons began enrolling patients undergoing revision ACL reconstruction, recording patient demographics, previous ACL reconstruction methods, intra-articular injuries, and current revision techniques. Enrolled subjects completed a questionnaire consisting of validated patient-based outcome measures. Results As of April 1, 2009, 87 surgeons have enrolled a total of 460 patients (57% men; median age, 26 years). For 89%, the reconstruction was the first revision. Mode of failure as deemed by the revising surgeon was traumatic (32%), technical (24%), biologic (7%), combination (37%), infection (Conclusion The MARS Group has been able to quickly accumulate the largest revision ACL reconstruction cohort reported to date. Traumatic reinjury is deemed by surgeons to be the most common single mode of failure, but a combination of factors represents the most common mode of failure. Allograft graft choice is more common in the revision setting than autograft. Concomitant knee injury is extremely common in this population.

Background Meniscal repair is performed in an attempt to prevent posttraumatic arthritis resulting from meniscal dysfunction after meniscal tears. The socioeconomic implications of premature arthritis are significant in the young patient population. Investigations and techniques focusing on meniscus preservation and healing are now at the forefront of orthopaedic sports medicine. Hypothesis Concomitant meniscal repair with anterior cruciate ligament reconstruction is a durable and successful procedure at 2-year follow-up. Study Design Case series; Level of evidence, 4. Methods All unilateral primary anterior cruciate ligament reconstructions entered in 2002 in a cohort who had meniscal repair at the time of anterior cruciate ligament reconstruction were evaluated. Validated patient-oriented outcome instruments were completed preoperatively and then again at the 2-year postoperative time point. Reoperation after the index procedure was also documented and confirmed by operative reports. Results A total of 437 unilateral primary anterior cruciate ligament reconstructions were performed with 82 concomitant meniscal repairs (54 medial, 28 lateral) in 80 patients during the study period. Patient follow-up was obtained on 94% (77 of 82) of the meniscal repairs, allowing confirmation of meniscal repair success (defined as no repeat arthroscopic procedure) or failure. The overall success rate for meniscal repairs was 96% (74 of 77 patients) at 2-year follow-up. Conclusion Meniscal repair is a successful procedure in conjunction with anterior cruciate ligament reconstruction. When confronted with a “repairable” meniscal tear at the time of anterior cruciate ligament reconstruction, orthopaedic surgeons can expect an estimated >90% clinical success rate at 2-year follow-up using a variety of methods as shown in our study.

Objectives: Knees undergoing revision ACL reconstruction (rACLR) have a high prevalence of articular cartilage lesions. The purpose of this study was to test the hypothesis that the prevalence of chondrosis at the time of rACLR is associated with meniscus status and lower extremity alignment. Methods: Data from the prospective Multicenter ACL Revision Study (MARS) cohort was reviewed to identify patients with pre-operative lower extremity alignment films. Lower extremity alignment was defined by the weight bearing line (WBL) as a percentage of the tibial plateau width, while the chondral and meniscal status of each weight bearing compartment was recorded at the time of surgery. Multivariable proportional odds models were constructed and adjusted for relevant factors in order to examine which risk factors were independently associated with the degree of medial and lateral compartment chondrosis. Results: The cohort included 246 patients with lower extremity alignment films at the time of rACLR. Average (SD) patient age was 26.9 (9.5) years with a BMI of 26.4 (4.6). The medial compartment had more chondrosis (Grade 2/3: 42%, Grade 4: 6.5%) than the lateral compartment (Grade 2/3: 26%, Grade 4: 6.5%). Disruption of the meniscus was noted in 35% of patients on the medial side and 16% in the lateral side. The average (SD) WBL was measured to be 0.43 (0.13). Medial compartment chondrosis was associated with BMI (p=0.025), alignment (p=0.002)(see figure), and medial meniscus status (p=0.001). None of the knees with the WBL lateral to 0.625 had Grade 4 chondrosis in the medial compartment. Lateral compartment chondrosis was significantly associated with age (p=0.013) and lateral meniscus status (pConclusion: The status of articular cartilage in the tibiofemoral compartments at the time of rACLR is related to meniscal status. Preserving the meniscus at the time of ACL reconstruction has the potential to be chondroprotective, particularly in patients who go on to require rACLR. Lower extremity alignment and BMI are associated with medial compartment chondrosis, suggesting that optimizing alignment and minimizing weight gain may be important in these patients.

Objectives: Limited research has examined the independent relationship between psychosocial factors and patient-reported outcomes during the early postoperative period following ACL reconstruction (ACLR). The purpose of this study was to examine the association between preoperative psychosocial characteristics and return to sport and sports function at 6 months after ACLR. A secondary objective was to examine the importance of psychosocial characteristics to knee-specific quality of life (QOL). Methods: Fifty-four patients, 18 to 33 years of age, undergoing a primary, unilateral ACLR were enrolled between November 2012 and December 2013. Demographic characteristics and a series of validated psychosocial and outcome measures were collected preoperatively. Patient expectations for having a successful surgery were assessed with a 10-item numeric rating scale. Fear of movement was measured with the activity avoidance and somatic focus subscales from the 13-item Tampa Scale for Kinesiophobia, pain catastrophizing with the Pain Catastrophizing Scale, depressive symptoms with the Patient Health Questionnaire-9, and general and knee-specific self-efficacy with the Generalized Self-Efficacy Scale and Knee Self-Efficacy Scale. Return to sport was assessed with the Subjective Patient Outcome for Return to Sport (SPORTS) and sports function and knee-specific QOL were assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales. Patients completed an identical set of outcome instruments at 6 months after surgery. Separate multivariable linear regression analyses were used to examine the association between preoperative psychosocial variables and patient-reported outcomes at 6 months after ACLR, controlling for age, education, and preoperative outcome score. Results: The follow-up rate at 6 months was 93%. Ninety-six percent of patients (48/50) reported returning to sport at 6 months after ACLR, with 46% returning at the same pre-injury level of effort and performance (Table 1). Higher preoperative activity avoidance scores was significantly associated with not returning to sport at same level of effort and performance as before onset of impairment (OR = .73, p = .02), and worse scores on the KOOS QOL subscale (β = -1.4, p = .05) at 6-month follow-up. Higher preoperative expectations was a significant risk factor for worse outcomes on the KOOS subscales, with a 1-point increase in expectations associated with a 5.6-point decrease in KOOS sports/rec (p = .03) and 4.7-point decrease in KOOS QOL (p = .05) scores. Preoperative pain catastrophizing, depression, and self-efficacy were not statistically associated with patient-reported outcomes (p > .05). Conclusion: Screening patients for fear of movement and unrealistic expectations prior to ALCR may help identify patients at-risk for poorer outcomes. Targeted psychosocial rehabilitation strategies that address activity avoidance related to fear and expectations have the potential to improve return to sport at same level of effort and performance and knee-specific health outcomes during the early recovery period.

The incidence of noncontact anterior cruciate ligament injuries in young to middle-aged athletes remains high. Despite early diagnosis and appropriate operative and nonoperative treatments, posttraumatic degenerative arthritis may develop. In a meeting in Atlanta, Georgia (January 2005), sponsored by the American Orthopaedic Society for Sports Medicine, a group of physicians, physical therapists, athletic trainers, biomechanists, epidemiologists, and other scientists interested in this area of research met to review current knowledge on risk factors associated with noncontact anterior cruciate ligament injuries, anterior cruciate ligament injury biomechanics, and existing anterior cruciate ligament prevention programs. This article reports on the presentations, discussions, and recommendations of this group.

Background An instrumented cadaveric knee construct was used to quantify the association between impact force, quadriceps force, knee flexion angle, and anterior cruciate ligament relative strain in simulated unipedal jump landings. Hypothesis Anterior cruciate ligament strain will correlate with impact force, quadriceps force, and knee flexion angle. Study Design Descriptive laboratory study. Methods Eleven cadaveric knees (age, 70.8 [19.3] years; 5 male; 6 female) were mounted in a custom fixture with the tibia and femur secured to a triaxial load cell. Quadriceps, hamstring, and gastrocnemius muscle forces were simulated using pretensioned steel cables (stiffness, 7 kN/cm), and the quadriceps tendon force was measured using a load cell. Mean strain on the anteromedial bundle of the anterior cruciate ligament was measured using a DVRT. With the knee in 25° of flexion, the construct was vertically loaded by an impact force initially directed 4 cm posterior to the knee joint center. Tibiofemoral kinematics was measured using a 3D optoelectronic tracking system. Results The increase in anterior cruciate ligament relative strain was proportional to the increase in quadriceps force (r2 = 0.74; P Conclusion The increase in knee flexion and quadriceps force during this simulated 1-footed landing strongly influenced the relative strain on the anteromedial bundle of the anterior cruciate ligament. Clinical Relevance These results suggest that even in the presence of knee flexor muscle forces, the increase in quadriceps force required to prevent the knee from flexing during landing can place the anterior cruciate ligament at risk for large strains.

Objectives: Identify the patient-reported outcomes (IKDC, KOOS, Marx activity scale) and patient-specific risk factors from a large prospective cohort at a minimum 10-year follow-up after ACL reconstruction. Methods: Unilateral ACL reconstructions were identified and prospectively enrolled between 2002 and 2004 from 7 sites in the Multicenter Orthopaedics Outcome Network (MOON). Patients pre-operatively d a series of validated outcome instruments, including the IKDC, KOOS, and Marx activity scale. At the time of surgery, physicians documented all intraarticular pathology, treatment, and surgical techniques utilized. Patients were followed at a minimum of 2, 6, and 10 years post-op, and asked to the same outcome instruments that they d at surgery (T0). Incidence and details of any subsequent knee surgeries were also obtained. Multivariable regression analysis was used to control for patient demographic variables, surgical technique and pathology variables, and incidence of subsequent surgery, in order to identify factors associated with patient-reported outcomes 10 years after ACL reconstruction. Results: A total of 1597 patients were eligible (57% male; median age 23 years). Ten-year follow-up was obtained on 83% (1320) [86% (1379) at 2 years, 86% (1375) at 6 years], while subsequent surgery data was obtained on over 90% of the cohort. Both IKDC and KOOS scores significantly improved after 2 years and were maintained at 6 and 10 years (Figure 1). Interestingly, Marx activity level scores dropped markedly over time, from a median score of 12 pts at baseline, 9 pts at 2 years, 7 pts at 6 years, to 6 pts at 10 years. The patient-specific risk factors for worse 10-year outcomes are shown in Table 1. The significant drivers of poorer outcomes were lower baseline outcome scores, higher BMI, smoker at baseline, history of medial meniscus surgery prior to ACL reconstruction, having a revision ACL reconstruction, grades 3-4 articular cartilage pathology in the medial, lateral and patellofemoral compartments, and having any subsequent ipsilateral surgery. Graft type (autograft BTB, autograft soft tissue, allograft), MCL or LCL pathology, and medial or lateral meniscus surgery at the time of ACL reconstruction were not found to be significant risk factors. Conclusion: Patients are able to perform sports-related functions and maintain a high knee-related quality of life 10 years after ACL reconstruction, although activity level declines over time. Multivariable analysis identified several key modifiable risk factors that significantly influence outcome. This prognostic information will undoubtedly aid physician counseling of patients’ expectations after ACL reconstruction at surgery and at 2 and 6 years to predict 10 year outcome. Table 1. Significant Predictors for Worse Outcome 11:1 Years after AGL Reconstruction IKDC KOOS Sports/Rec KOOS QOL Marx Activity Level • Low baseline IKDC score • Low baseline KOOS Sports/rec score • Low baseline KOOS QOL score • Low baseline Marx score • Low baseline activily level • Low baseline activily level • Low baseline activily level • Higher age • Higher age • Higher age • Gender (female) • Gender (female) • Gender (female) • Higher BMI • Higher BMI • Higher BMI • Higher BMI • Smoker • Smoker • Smoker • Lower education level • Lower education level • Revision ACLR • Revision ACLR • Revision ACLR • Previous medial meniscus. Surgery • Previous medial meniscus. Surgery • Previous medial meniscus. Surgery • Previous medial meniscus. Surgery • Previous lateral meniscus. Surgery • AC medial pathology (Grades 3/4) • AC medial pathology (Grades 3/4) • AC medial pathology (Grades 2/3/4) • AC lateral pathology (Grades 3/4) • AC lateral pathology (Grades 3/4) • AC lateral pathology (fracture. lines) • AC patellofemoral pathology (Grades 3/4) • AC patellofemoral pathology (Grades 3/4) • AC patellofemoral pathology (Grades 3/4) • High-grade laxity • Subsequent surgery (IL knee) • Subsequent surgery (IL knee) • Subsequent surgery (IL knee)

Strenuous physical activity is known to cause structural abnormalities in the immature vertebral body. Concern that exposure to years of intense athletic training may increase the risk for developing adolescent hyperkyphosis in certain sports, as well as the known association between hyperkyphosis and adult-onset back pain, led us to examine the association between cumulative hours of athletic training and the magnitude of the sagittal curvature of the immature spine. A sample of 2270 children (407 girls and 1863 boys) between 8 and 18 years of age were studied. An optical rasterstereographic method was used to measure the mid-sagittal curvatures of the surface of the back while the subject was in the upright standing position to quantify the angles of thoracic kyphosis and lumbar lordosis. These data were then correlated with self-reported hours of training measured by interview and questionnaire. The possible effects of age, sex, sport, and upper and lower body weight training were investigated. The results in these young athletes showed that larger angles of thoracic kyphosis and lumbar lordosis were associated with greater cumulative training time. Gymnasts showed the largest curves. Lack of sports participation, on the other hand, was associated with the smallest curves. Age and sex did not appear to affect the degree of curvature.

We examined persons after anterior cruciate ligament injury and for 1.5 years after anterior cruciate ligament reconstruction to analyze changes in anterior knee laxity, lower extremity muscle strength, endurance, and several parameters of neuromuscular function. Sixteen men and nine women (average age, 23.8 years) were evaluated preoperatively, then underwent intraarticular autogenous patellar tendon anterior cruciate ligament reconstruction by the same surgeon and were evaluated at 6, 12, and 18 months postoperatively. Muscle strength was measured isokinetically and neuromuscular function was quantified with simultaneous anterior tibial translation and surface electromyography tests. Forty subjects (26 men and 14 women; average age, 23.5 years) with no known knee abnormalities served as the control group. Subjective questionnaire results showed that by 18 months postoperatively, 20 subjects (80%) believed they had regained their preoperative levels of function. Unfortunately, muscle function in most subjects had not returned to normal. At 12 to 18 months postoperatively, when knee rehabilitation was terminated, significant deficiencies in muscle performance persisted in most patients. Interestingly, in this group of stable knees, quadriceps and hamstring muscle reaction times appeared to be the best objective indicators of subjective knee function.

The late-cocking phase of throwing is characterized by extreme external rotation of the abducted arm; repeated stress in this position is a potential source of glenohumeral joint laxity. To determine the ligamentous restraints for external rotation in this position, 20 cadaver shoulders (mean age, 65 +/- 16 years) were dissected, leaving the rotator cuff tendons, coracoacromial ligament, glenohumeral capsule and ligaments, and coracohumeral ligament intact. The combined superior and middle glenohumeral ligaments, anterior band of the inferior glenohumeral ligament, and the entire inferior glenohumeral ligament were marked with sutures during arthroscopy. Specimens were mounted in a testing apparatus to simulate the late-cocking position. Forces of 22 N were applied to each of the rotator cuff tendons. An external rotation torque (0.06 N x m/sec to a peak of 3.4 N x m) was applied to the humerus of each specimen with the capsule intact and again after a single randomly chosen ligament was cut (N = 5 in each group). Cutting the entire inferior glenohumeral ligament resulted in the greatest increase in external rotation (10.2 degrees +/- 4.9 degrees). This was not significantly different from sectioning the coracohumeral ligament (8.6 degrees +/- 7.3 degrees). The anterior band of the inferior glenohumeral ligament (2.7 degrees +/- 1.5 degrees) and the superior and middle glenohumeral ligaments (0.7 degrees +/- 0.3 degrees) were significantly less important in limiting external rotation.

Anterior cruciate ligament injury rates are four to eight times higher in women than in men. Because of estrogen's direct effect on collagen metabolism and behavior and because neuromuscular performance varies during the menstrual cycle, it is logical to question the menstrual cycle's effect on knee injury rates. Of 40 consecutive female athletes with acute anterior cruciate ligament injuries (less than 3 months), 28 (average age, 23 11 years) met the study criteria of regular menstrual periods and noncontact injury. Details concerning mechanism of injury, menstrual cycle, contraceptive use, and previous injury history were collected. A chi-square test was used to compute observed and expected frequencies of anterior cruciate ligament injury based on three different phases of the menstrual cycle: follicular (days 1 to 9), ovulatory (days 10 to 14), and luteal (day 15 to end of cycle). A significant statistical association was found between the stage of the menstrual cycle and the likelihood for an anterior cruciate ligament injury (P 0.03). In particular, there were more injuries than expected in the ovulatory phase of the cycle. In contrast, significantly fewer injuries occurred in the follicular phase. These hormones may be a factor in the knee ligament injury dilemma in women.

Objectives: Identifying risk factors for inferior outcomes after ACL reconstruction (ACLR) is important for prognosis and future treatment. Study goal: analyze a sufficiently large enough cohort to evaluate whether articular cartilage and meniscal variables are predictive of three validated sports outcome instruments. We hypothesized that articular cartilage lesions and meniscus tears/treatment would be predictors of IKDC, KOOS (all 5 subscales), and Marx Activity Level at 6 years after ACLR. Methods: From 2002-2004, 1411 ACLR subjects were prospectively enrolled and followed longitudinally with the IKDC, KOOS, and Marx completed at entry, 2 and 6 years. A logistic multivariable model consisted of patient demographics, surgical technique variables, and articular cartilage injuries and meniscus tears/treatment for determining predictors (risk factors) of IKDC, KOOS, and Marx at 6 years. Results: We completed a minimum follow-up on 93% (1307/1411) of our cohort at 6 years. Baseline results: 56% male, median age 23 years, 75% with non-contact injury mechanism, articular cartilage pathology (MFC-25%, LFC-20%, MTP-6%, LTP-12%, patella-20%, and trochlear-9%), and meniscal pathology (medial-38%, lateral-46%). Both articular cartilage lesions and meniscal tears significantly predicted 6 year outcomes on IKDC and KOOS (Table 1). Grade 3 or 4 articular cartilage lesions (excluding patella) significantly reduced IKDC and KOOS scores at 6 years. Figure 1 focuses on IKDC and demonstrates worse outcomeswith chondral injuries on the MFC, MTP, and LFC. Likewise, KOOS was negatively affected by cartilage injury. The sole significant predictor of reduced Marx activity was the presence of a grade 4 lesion on the MFC. Lateral meniscus repairs did not correlate with inferior results, but medial meniscus repairs predicted worse IKDC and KOOS scores. Lateral meniscus tears left alone significantly improved prognosis. Small partial meniscectomies (50%) improved prognosis. Analogous to previous studies, other significant predictors of worse outcome scores were lower baseline scores, higher BMI, lower education level, smoking, and revisions. Conclusion: Both articular cartilage injury and meniscal tears/treatment at the time of ACLR were significant predictors of both IKDC and KOOS scores at 6 year follow-up. Similarly, having a grade 4 MFC lesion significantly reduced a patient’s Marx activity level score at 6 years.

We investigated the effect of quadriceps and hamstring muscle fatigue on anterior tibial translation and muscle reaction time in 10 healthy subjects. The six men and four women had an average age of 21.3 years and had no known pathologic knee conditions. Each patient underwent a knee examination, arthrometer measure ments of tibial translation, subjective functional assess ment, and an anterior tibial translation stress test be fore and after quadriceps and hamstring muscle- fatiguing exercise. The recruitment order of the lower extremity muscles in response to anterior tibial trans lation did not change with muscle fatigue. However, the results showed an average increase of 32.5% in ante rior tibial translation (range, 11.4% to 85.2%) after fatigue. Muscle responses in the gastrocnemius, ham string, and quadriceps originating at the spinal cord and cortical level showed significant slowing and, in some cases, an absence of activity after the quadri ceps and hamstring muscles were fatigued. The in creases in displacement after fatigue strongly corre lated (0.62 to 0.96) with a delay in cortical-level activity (intermediate and voluntary). Muscle fatigue, which ap pears to affect the dynamic stability of the knee, alters the neuromuscular response to anterior tibial transla tion. Therefore, fatigue may play an important role in the pathomechanics of knee injuries in physically de manding sports.

The purpose of this research was to identify possible predisposing neuromuscular factors for knee injuries, particularly anterior cruciate ligament tears in female athletes by investigating anterior knee laxity, lower extremity muscle strength, endurance, muscle reaction time, and muscle recruitment order in response to anterior tibial translation. We recruited four subject groups: elite female ( N = 40) and male ( N = 60) athletes and sex-matched nonathletic controls ( N = 40). All participants underwent a subjective evaluation of knee function, arthrometer measurement of anterior tibial translation, isokinetic dynamometer strength and endurance tests at 60 and 240 deg/sec, and anterior tibial translation stress tests. Dynamic stress testing of muscles demonstrated less anterior tibial translation in the knees of the athletes (both men and women) com pared with the nonathletic controls. Female athletes and controls demonstrated more anterior tibial laxity than their male counterparts and significantly less mus cle strength and endurance. Compared with the male athletes, the female athletes took significantly longer to generate maximum hamstring muscle torque during isokinetic testing. Although no significant differences were found in either spinal or cortical muscle reaction times, the muscle recruitment order in some female athletes was markedly different. The female athletes appeared to rely more on their quadriceps muscles in response to anterior tibial translation; the three other test groups relied more on their hamstring muscles for initial knee stabilization.

The routine use of functional knee braces in the ante rior cruciate ligament-deficient, injured, or recon structed knee, lacks biomechanical support. Although subjective reports favoring bracing are plentiful, objec tive proof of significant control of tibial translation is not. This in vivo study was designed to assess the effect of six popular braces on anterior tibial translation, isoki netic performance, and neuromuscular function in five chronically unstable anterior cruciate ligament-defi cient knees. A knee stress test was performed on a specially designed device that allowed free tibial move ment while monitoring anterior tibial translation and muscle function in the quadriceps, hamstring, and gas trocnemius muscles. Results show that braces can decrease anterior tibial translation between 28.8% and 39.1% without the stabilizing contractions of the ham string, quadriceps, and gastrocnemius muscles. With lower extremity muscle activation and bracing, anterior tibial translation was decreased between 69.8% and 84.9%. Some improvement in spinal level muscle re action times was seen with brace use, especially in the quadriceps muscle. Unfortunately, most braces appear to consistently slow hamstring muscle reaction times at the voluntary level.

Weight training is an integral part of most athletic con ditioning programs; yet, the effect of these programs on neuromuscular function remains unclear. To exam ine the neuromuscular effects of training and condition ing at the knee joint, 32 volunteers (16 men and 16 women; average age, 25.4 years) were placed into one of four groups: isokinetic, isotonic, agility, or control. Each group trained 3 days per week for 6 weeks. The knee function of all participants was evaluated just before and after the 6-week training period. The agility- trained group significantly improved the spinal reflex times of the lateral and medial quadriceps muscles in response to anterior tibial translation. The cortical re sponse time of the agility group also significantly im proved in the gastrocnemius, medial hamstring, and the lateral quadriceps muscles. Interestingly, the corti cal response time of the medial hamstring and the medial quadriceps muscles in the isokinetic group slowed significantly, by 39.1 and 32.4 msec, respec tively, after 6 weeks of training. Isotonic and isokinetic strength training of the lower extremities do not appear to improve muscle reaction time to anterior tibial trans lation, whereas agility exercises potentially improve this parameter.