Search

Objective and design The purpose of this study was to compare synovial concentrations of pro- and anti-inflammatory cytokines between multiple-ligament knee injured (MLKI) and anterior cruciate ligament (ACL)-injured patients. Subjects 14 patients with MLKI and 10 patients with isolated ACL injury Methods Synovial fluid was aspirated from the operative knee at the time of surgery and the concentrations of pro- and anti-inflammatory markers in the synovial fluid were determined. Structures injured, the time between injury and surgery, and demographic factors were collected. Linear regressions were used to determine the association between injury pattern and synovial inflammatory markers when controlling for age, BMI, and time between injury and surgery. Results When adjusting for group differences in age, BMI and the time between injury and surgery, no group differences were detected (interferon gamma (p = 0.11), interleukin-1beta (IL-1b, p = 0.35), IL-2 (p = 0.28), IL-4 (p = 0.64), IL-6 (p = 0.37), IL-8 (p = 0.54), IL-10 (p = 0.25), IL-12p70 (p = 0.81), IL-13 (p = 0.31), and tumor necrosis factor-alpha (p = 0.90)). Conclusion Synovial fluid inflammatory markers did not differ between MLKI and isolated ACL injuries. MLKIs have a greater prevalence of postoperative arthrofibrosis when compared to isolated ACL injuries; however, this may be due in part to factors other than the inflammatory status of the joint.

The objective of the study was to determine if psychological readiness for sport and knee self-efficacy assessed early (3 months) after anterior cruciate ligament reconstruction (ACLR) are predictive of self-reported functional outcomes, quadriceps strength, and knee mechanics while running at the time of return to sport training (6 months). Thirty athletes with unilateral ACLR completed the ACL Return to Sport after Injury (ACL-RSI) and Knee Self-Efficacy Scale (K-SES) 3 months after ACLR and completed self-reported functional outcomes, isometric quadriceps strength testing, and three-dimensional running gait analysis 6 months after ACLR. The 3-month ACL-RSI significantly correlated with the 6-month International Knee Documentation Committee (IKDC; r = 0.565, p = 0.001), Knee Injury and Osteoarthritis Outcome Score (KOOS) sport/recreational activities (KOOSSport ; r = 0.548, p = 0.002) and quality of life (KOOSQoL ; r = 0.431, p = 0.017), and quadriceps strength (r = 0.528, p = 0.003). The 3-month K-SES significantly correlated with the 6-month IKDC (r = 0.528, p = 0.003), KOOSSport (r = 0.430, p = 0.018), KOOSQoL (r = 0.411, p = 0.024), quadriceps strength (r = 0.465, p = 0.010), and knee flexion excursion (r = 0.472, p = 0.008). With multivariate modeling, both the ACL-RSI and K-SES were predictive of the IKDC (R2 = 0.411; p = 0.001). Only the ACL-RSI was predictive of the KOOSSport (R2 = 0.300; p = 0.002), KOOSQoL (R2 = 0.186; p = 0.017), and quadriceps strength (R2 = 0.279; p = 0.003), whereas only the K-SES was predictive of knee flexion excursion (R2 = 0.173; p = 0.022). Athletes with greater psychological readiness for sport and knee self-efficacy at 3 months demonstrated higher scores on self-reported functional outcomes, greater quadriceps strength, and greater knee flexion excursion at 6 months after ACLR. This study indicates that psychosocial measures may be important to include into early post-surgical evaluations to help guide and facilitate interventions to restore subjective and objective knee function.

Background: Knee joint power is significantly impaired during the propulsive phase of jumping after anterior cruciate ligament reconstruction (ACLR); however, it is currently unknown how quadriceps strength influences knee joint power. Purpose: To (1) evaluate the relationship between quadriceps strength, joint power, and the percentage contribution of the hip, knee, and ankle joints to total limb power during the propulsive phase of jumping and (2) establish a quadriceps strength cutoff value for maximizing the likelihood of having knee joint power characteristics similar to healthy participants. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 75 participants were included in this study—40 patients who underwent ACLR 6 months before (18 females; mean age, 19.3 ± 5.7 years) and 35 healthy controls (HC) (20 females; mean age, 21.5 ± 4.5 years). Participants performed a drop vertical jump and underwent isometric quadriceps strength testing. The peak joint power was calculated as the product of the internal joint moment and joint angular velocity. Pearson product-moment correlations were used to assess the relationship between quadriceps strength and knee joint power. Paired samples t tests were used to quantify differences between limbs. Receiver operating characteristic (ROC) curve analysis was used to determine a quadriceps strength cutoff. Results: The involved limbs of the ACLR cohort (INV) had significantly lower peak knee joint power and percentage contribution from the knee joint during jumping compared with the uninvolved limbs (NON) and limbs of the controls (INV, 2.5 ± 1.2 W/kg; NON, 4.4 ± 1.5 W/kg; HC, 4.3 ± 1.7 W/kg [ P < .0001]). Quadriceps strength was associated with knee joint power in involved limbs and limbs of controls (INV, r = 0.50; HC, r = 0.60). A quadriceps strength cutoff value of 2.07 N·m/kg had an area under the ROC curve of 0.842, indicating good predictive accuracy. Conclusion: Athletes at 6 months after ACLR demonstrated knee-avoidant jumping mechanics and had significant reductions in knee joint power on the involved limb. A quadriceps strength cutoff value of 2.07 N·m/kg can help predict which athletes will display knee joint power characteristics similar to those of healthy controls.

PURPOSE Elevated synovial fluid (SF) concentrations of proinflammatory cytokines, degradative enzymes, and cartilage breakdown markers at the time of anterior cruciate ligament (ACL) reconstruction are associated with worse postoperative patient-reported outcomes and cartilage quality. However, it remains unclear if this is due to a more robust or dysregulated inflammatory response or is a function of a more severe injury. The objective of this study was to evaluate the association of the molecular composition of the SF, patient demographics, and injury characteristics to cartilage degradation after acute ACL injury. METHODS We performed a cluster analysis of SF concentrations of proinflammatory and anti-inflammatory cytokines, and biomarkers of cartilage degradation, bony remodeling, and hemarthrosis. We evaluated the association of biomarker clusters with patient demographics, days between injury, Visual Analogue Scale pain, SF aspirate volumes, and bone bruise volumes measured on magnetic resonance imaging. RESULTS Two clusters were identified from the 35 patients included in this analysis, dysregulated inflammation and low inflammation. The dysregulated inflammation cluster consisted of 10 patients and demonstrated significantly greater concentrations of biomarkers of cartilage degradation (P < 0.05) as well as a lower ratio of anti-inflammatory to proinflammatory cytokines (P = 0.053) when compared with the low inflammation cluster. Patient demographics, bone bruise volumes, SF aspirate volumes, pain, and concomitant injuries did not differ between clusters. CONCLUSIONS A subset of patients exhibited dysregulation of the inflammatory response after acute ACL injury which may increase the risk of posttraumatic osteoarthritis. This response does not appear to be a function of injury severity.

Background: Anterior cruciate ligament (ACL) tears result in significant quadriceps muscle atrophy that is resistant to recovery despite extensive rehabilitation. Recent work suggests an elevated fibrotic burden in the quadriceps muscle after the injury, which may limit recovery. Elucidating the mechanisms and cell types involved in the progression of fibrosis is critical for developing new treatment strategies. Purpose: To identify factors contributing to the elevated fibrotic burden found after the injury. Study Design: Descriptive laboratory study. Methods: After an ACL injury, muscle biopsy specimens were obtained from the injured and noninjured vastus lateralis of young adults (n = 14, mean ± SD: 23 ± 4 years). The expression of myostatin, transforming growth factor β, and other regulatory factors was measured, and immunohistochemical analyses were performed to assess turnover of extracellular matrix components. Results: Injured limb skeletal muscle demonstrated elevated myostatin gene ( P < .005) and protein ( P < .0005) expression, which correlated ( R2 = 0.38, P < .05) with fibroblast cell abundance. Immunohistochemical analysis showed that human fibroblasts express the activin type IIB receptor and that isolated primary human muscle-derived fibroblasts increased proliferation after myostatin treatment in vitro ( P < .05). Collagen 1 and fibronectin, primary components of the muscle extracellular matrix, were significantly higher in the injured limb ( P < .05). The abundance of procollagen 1–expressing cells as well as a novel index of collagen remodeling was also elevated in the injured limb ( P < .05). Conclusion: These findings support a role for myostatin in promoting fibrogenic alterations within skeletal muscle after an ACL injury. Clinical Relevance: The current work shows that the cause of muscle quality decline after ACL injury likely involves elevated myostatin expression, and future studies should explore therapeutic inhibition of myostatin to facilitate improvements in muscle recovery and return to sport.

Context: There is a lack of consensus regarding test batteries for return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR). Objective: To report the RTS test batteries for individuals after ACLR and to examine alignment with the American Academy of Orthopaedic Surgeons (AAOS) Appropriate Use Criteria (AUC). Finally, to examine how published RTS batteries prior to the AAOS AUC (2010-2015) compared with those after publication of the AUC (2016-2020). Data Source: A systematic search of PubMed (2010-2020). Study Selection: Studies were included if they were published from 2010 to 2020, patients underwent primary ACLR and were tested between 6 months and 2 years postoperatively and included a minimum of 2 assessments. Studies were excluded if patients were tested outside the designated time; had undergone a revision, contralateral, or multiligament injury; included healthy participants; were level 5 evidence or the study was a systematic review. A total of 1012 articles were reviewed and 63 met the criteria. Study Design: Systematic review. Level of Evidence: Level 4. Data Extraction: Information regarding the RTS batteries and patient demographics were extracted from the included articles. Results: A total of 63 studies met the inclusion and exclusion criteria (22 from 2010-2015 and 41 from 2016-2020). The most common RTS batteries included the hop test, quadriceps strength test, and patient-reported outcome measures. No study met all 7 AUC; the most common criteria met were functional skills (98.4%), followed by confidence (22.2%), then range of motion and knee stability (20.6%). Conclusion: The test batteries in the current literature show high variability and a lack of essential components necessary for RTS. No study met the AUC guidelines, suggesting a disconnect between recommended guidelines and clinical practice. Test battery research has expanded over the past decade; however, standardized, clinically applicable batteries that encompass all criteria are needed.

Background:Many patients live with long-term deficits in knee function after an anterior cruciate ligament reconstruction (ACLR). However, research is inconclusive as to which physical performance measure is most strongly related to long-term patient-reported outcomes after ACLR.Hypothesis:Quadriceps strength would be most strongly associated with patient-reported long-term outcomes after ACLR.Study Design:Cross-sectional study.Level of Evidence:Level 3.Methods:A total of 40 patients (29 female) consented and participated an average of 10.9 years post-ACLR (range, 5-20 years). Patients completed the Lower Extremity Functional Scale (LEFS), the International Knee Documentation Committee (IKDC) Scale, Knee injury and Osteoarthritis Outcome Score Quality of Life (KOOS QoL) and Sport (KOOS Sport) subscales, and the Tampa Scale of Kinesiophobia (TSK-17). Each patient subsequently performed maximal isometric quadriceps contraction, a 60-second single-leg step-down test, and the single-leg single hop and triple hop for distance tests. Multivariate linear and logistic regression models determined how performance testing was associated with each patient-reported outcome when controlling for time since surgery, age, and TSK-17.Results:When controlling for time since surgery, age at the time of consent, and TSK-17 score, maximal isometric quadriceps strength normalized to body weight was the sole physical performance measure associated with IKDC ( P < 0.001), KOOS Sport ( P = 0.006), KOOS QoL ( P = 0.001), and LEFS scores ( P < 0.001). Single-leg step-down, single hop, and triple hop did not enter any of the linear regression models ( P > 0.20). Additionally, TSK-17 was associated with all patient-reported outcomes ( P ≤ 0.01) while time since surgery was not associated with any outcomes ( P > 0.05).Conclusion:Isometric quadriceps strength and kinesiophobia are significantly associated with long-term patient-reported outcomes after ACLR.Clinical Relevance:These results suggest that training to improve quadriceps strength and addressing kinesiophobia in the late stages of recovery from ACLR may improve long-term self-reported function.

Background. The majority of patients develop posttraumatic osteoarthritis within 15 years of anterior cruciate ligament (ACL) injury. Inflammatory and chondrodegenerative biomarkers have been associated with both pain and the progression of osteoarthritis; however, it remains unclear if preoperative biomarkers differ for patients with inferior postoperative outcomes. Hypothesis/Purpose. The purpose of this pilot study was to compare biomarkers collected on the day of ACL reconstruction between patients with “good” or “poor” 2-year postoperative outcomes. We hypothesized that inflammatory cytokines and chondrodegenerative biomarker concentrations would be significantly greater in patients with poorer outcomes. Study Design. Prospective cohort design. Methods. 22 patients (9 females, 13 males; age = 19.5±4.1 years; BMI = 24.1±3.6 kg/m2) previously enrolled in a randomized trial evaluating early anti-inflammatory treatment after ACL injury. Biomarkers of chondrodegeneration and inflammation were assessed from synovial fluid (sf) samples collected on the day of ACL reconstruction. Participants completed Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) questionnaires two years following surgery. Patients were then categorized based on whether their KOOS Quality of Life (QOL) score surpassed the Patient Acceptable Symptom State (PASS) threshold of 62.5 points or the IKDC PASS threshold of 75.9 points. Results. Patients that failed to reach the QOL PASS threshold after surgery (n = 6, 27%) had significantly greater sf interleukin-1 alpha (IL-1α; p = 0.004), IL-1 receptor antagonist (IL-1ra; p = 0.03), and matrix metalloproteinase-9 (MMP-9; p = 0.01) concentrations on the day of surgery. Patients that failed to reach the IKDC PASS threshold (n = 9, 41%) had significantly greater sf IL-1α (p = 0.02). Conclusion. These pilot data suggest that initial biochemical changes after injury may be an indicator of poor outcomes that are not mitigated by surgical stabilization alone. Biological adjuvant treatment in addition to ACL reconstruction may be beneficial; however, these data should be used for hypothesis generation and more definitive randomized clinical trials are necessary.

Quadriceps strength and single-leg hop performance are commonly evaluated prior to return to sport after anterior cruciate ligament reconstruction (ACLR). However, few studies have documented potential hip strength deficits after ACLR, or ascertained the relative contribution of quadriceps and hip strength to hop performance.Patients cleared for return to sports drills after ACLR were compared to a control group. Participants' peak isometric knee extension, hip abduction, hip extension, and hip external rotation (HER) strength were measured. Participants also performed single-leg hops, timed hops, triple hops, and crossover hops. Between-limb comparisons for the ACLR to control limb and the non-operative limb were made using independent two-sample and paired sample t tests. Pearson's correlations and stepwise multiple linear regression were used to determine the relationships and predictive ability of limb strength, graft type, sex, and limb dominance to hop performance.Sixty-five subjects, 20 ACLR [11F, age 22.8 (15-45) years, 8.3 ± 2 months post-op, mass 70.47 ± 12.95 kg, height 1.71 ± 0.08 m, Tegner 5.5 (3-9)] and 45 controls [22F, age 25.8 (15-45) years, mass 74.0 ± 15.2 kg, height 1.74 ± 0.1 m, Tegner 6 (3-7)], were tested. Knee extension (4.4 ± 1.5 vs 5.4 ± 1.8 N/kg, p = 0.02), HER (1.4 ± 0.4 vs 1.7 ± 0.5 N/kg, p = 0.04), single-leg hop (146 ± 37 vs 182 ± 38% limb length, p 0.01), triple hop (417 ± 106 vs 519 ± 102% limb length, p 0.01), timed hop (3.3 ± 2.0 vs 2.3 ± 0.6 s, p 0.01), and crossover hop (364 ± 107 vs 446 ± 123% limb length, p = 0.01) were significantly impaired in the operative versus control subject limbs. Similar deficits existed between the operative and non-operative limbs. Knee extension and HER strength were significantly correlated with each of the hop tests, but only HER significantly predicted hop performance.After ACLR, patients have persistent HER strength, knee extension strength, and hop test deficits in the operative limb compared to the control and non-operative limbs, even after starting sport-specific drills. Importantly, HER strength independently predicted hop performance. Based on these findings, to resolve between-limb deficits in strength and hop performance clinicians should include HER strengthening exercises in post-operative rehabilitation.Prognostic Study, Level II.

As the incidence of anterior cruciate ligament (ACL) reconstruction continues to increase, the rate of revision surgery continues to climb. Revision surgery has inherent challenges that must be addressed in order to achieve successful results. The cause of the primary ACL reconstruction failure should be determined, and careful preoperative planning should be performed to address the cause(s) of failure. Each patient undergoing revision surgery should undergo a thorough history and physical examination, receive full length alignment radiographs, lateral radiographs, 45-degree flexion weight-bearing postero-anterior radiographs, and patellofemoral radiographs. 3-dimensional computed topography (CT) scan should be performed to assess tunnel position and widening. Magnetic resonance imaging (MRI) should be used to assess for intra-articular soft tissue pathology. Meniscal tears, meniscal deficiency, anterolateral capsule injuries, bony morphology, age, activity level, connective tissue diseases, infection, graft choice, and tunnel position can all impact the success of ACL reconstruction surgery. Meniscal lesions should be repaired, and in cases of persistent rotatory instability, extra-articular procedures may be indicated. Furthermore, osteotomies may be needed to correct malalignment or excess posterior tibial slope. Depending on the placement and condition of the original femoral and tibial tunnels, revision surgery may be performed in a single procedure or in a staged manner. In most cases, the surgery can be performed in one procedure. Regardless, the surgeon must communicate with the patient openly regarding the implications of revision ACL surgery and the treatment plan should be developed in a shared fashion between the surgeon and the patient.

Anterior cruciate ligament (ACL) injuries are associated with significant loss of strength in knee extensor muscles that persists despite physical therapy. The underlying mechanisms responsible for this protracted muscle weakness are poorly understood; however, we recently showed significant myofiber atrophy and altered muscle phenotype following ACL injury. We sought to further explore perturbations in skeletal muscle morphology and progenitor cell activity following an ACL injury. Muscle biopsies were obtained from the injured and non-injured vastus lateralis of young adults (n = 10) following ACL injury, and histochemical/immunohistochemical analyses were undertaken to determine collagen content, abundance of connective tissue fibroblasts, fibrogenic/adipogenic progenitor (FAP) cells, satellite cells, in addition to indices of muscle fiber denervation and myonuclear apoptosis. The injured limb showed elevated collagen content (p

Background: Factors and details regarding return to play in elite, collegiate female soccer athletes after an anterior cruciate ligament (ACL) injury and reconstruction have not been well studied. Purpose: To evaluate return to play among collegiate female soccer players, specifically examining the effect of surgical and individual athlete characteristics on the return-to-play rate. Study Design: Descriptive epidemiology study. Methods: Sports medicine and athletic training staff at institutions from the National Collegiate Athletic Association Southeastern Conference (SEC) were contacted to request participation in the study. All institutions were sent a standardized spreadsheet with response choices and instructions regarding athlete inclusion criteria. Athlete, injury, surgical technique, and return-to-play data were requested for ACL reconstructions performed on female soccer athletes at the participating institutions over the previous 8 years. χ2 analyses were used to compare the return-to-play rate by year in school, scholarship status, position, depth chart status, procedure, graft type, graft fixation, concomitant procedures, and previous ACL injuries. Results: All 14 of the SEC institutions chose to participate and provided data. A total of 80 ACL injuries were reported, with 79 surgical reconstructions and return-to-play data for 78 collegiate soccer athletes. The overall return-to-play rate was 85%. There was a statistical significance in return-to-play rates favoring athletes in earlier years of eligibility versus later years ( P < .001). Athletes in eligibility years 4 and 5 combined had a return-to-play rate of only 40%. Scholarship status likewise showed significance ( P < .001), demonstrating a higher return-to-play rate for scholarship athletes (91%) versus nonscholarship athletes (46%). No significant differences in return-to-play rates were observed based on surgical factors, including concomitant knee procedures, graft type, and graft fixation method. Conclusion: Collegiate female soccer athletes have a high initial return-to-play rate. Undergoing ACL reconstruction earlier in the college career as well as the presence of a scholarship had a positive effect on return to play. Surgical factors including graft type, fixation method, tunnel placement technique, concomitant knee surgeries, and revision status demonstrated no significant effect on the return-to-play rate.

Tunnel malposition is one of the most common technical reasons for anterior cruciate ligament reconstruction failure. Small changes in tunnel placement can result in significant differences in outcome. More anatomic placement of the tunnels can lead to greater knee stability and a more accurate reproduction of native knee kinematics. This Technical Note describes 2 tibial tunnel–independent methods to obtain anatomic femoral tunnel placement. The all-inside anteromedial portal technique requires only minimal surgical incisions but allows precise femoral tunnel placement. However, hyperflexion of the knee is required, adequate surgical assistance is necessary, and this technique may be susceptible to graft-tunnel mismatch. The outside-in technique may be more beneficial in obese patients, skeletally immature patients, or revision cases. On the downside, it does require an additional 2-cm surgical incision. This article also provides surgical pearls to fine-tune tibial tunnel placement.

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\Purpose Despite the intense focus on outcomes following an anterior cruciate ligament (ACL) reconstruction, it is not yet known whether unresolved abnormal hip and trunk neuromuscular control exists. The purpose of this study was to compare trunk and hip kinematics during running, hip abductor and external rotator strength, and trunk control between females who had undergone an ACL reconstruction and healthy control participants.

Individuals who have had an anterior cruciate ligament (ACL) tear and reconstruction continue to experience substantial knee extensor strength loss despite months of physical therapy. Identification of the alterations in muscle morphology and cellular composition are needed to understand potential mechanisms of muscle strength loss, initially as the result of the injury and subsequently from surgery and rehabilitation. We performed diffusion tensor imaging-magnetic resonance imaging and analyzed muscle biopsies from the vastus lateralis of both the affected and unaffected limbs before surgery and again from the reconstructed limb following the completion of rehabilitation. Immunohistochemistry was done to determine fiber type and size, Pax-7-positive (satellite) cells, and extracellular matrix (via wheat germ agglutinin straining). Using the diffusion tensor imaging data, the fiber tract length, pennation angle, and muscle volume were determined, yielding the physiological cross-sectional area (PCSA). Paired t tests were used to compare the effects of the injury between injured and uninjured limbs and the effects of surgery and rehabilitation within the injured limb. We found significant reductions before surgery in type-IIA muscle cross-sectional area (CSA; p = 0.03), extracellular matrix (p < 0.01), satellite cells per fiber (p < 0.01), pennation angle (p = 0.03), muscle volume (p = 0.02), and PCSA (p = 0.03) in the injured limb compared with the uninjured limb. Following surgery, these alterations in the injured limb persisted and the frequency of the IIA fiber type decreased significantly (p < 0.01) and that of the IIA/X hybrid fiber type increased significantly (p < 0.01). Significant and prolonged differences in muscle quality and morphology occurred after ACL injury and persisted despite reconstruction and extensive physical therapy. These results suggest the need to develop more effective early interventions following an ACL tear to prevent deleterious alterations within the quadriceps.

Anterior cruciate ligament (ACL) injuries are associated with significant loss of strength in knee extensor muscles that persists despite physical therapy. The underlying mechanisms responsible for this protracted muscle weakness are poorly understood; however, we recently showed significant myofiber atrophy and altered muscle phenotype following ACL injury. We sought to further explore perturbations in skeletal muscle morphology and progenitor cell activity following an ACL injury. Muscle biopsies were obtained from the injured and non-injured vastus lateralis of young adults (n = 10) following ACL injury, and histochemical/immunohistochemical analyses were undertaken to determine collagen content, abundance of connective tissue fibroblasts, fibrogenic/adipogenic progenitor (FAP) cells, satellite cells, in addition to indices of muscle fiber denervation and myonuclear apoptosis. The injured limb showed elevated collagen content (p 0.05), in addition to a greater abundance of fibroblasts and FAPs (p 0.05) in the injured limb. Fibroblast content was correlated with increased accumulation of extracellular matrix in the injured limb as well. A higher frequency of interstitial nuclei were positive for phospho-SMAD3 in the injured limb (p 0.05), providing some evidence for activation of a fibrogenic program through transforming growth factor β following an ACL injury. The injured limb also displayed reduced satellite cell abundance, increased fiber denervation and DNA damage associated with apoptosis (p 0.05), indicating alterations within the muscle itself after the ligament injury. Injury of the ACL induces a myriad of negative outcomes within knee extensor muscles, which likely compromise the restorative capacity and plasticity of skeletal muscle, impeding rehabilitative efforts. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1876-1885, 2017.

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.

Despite significant rehabilitation, many athletes experience protracted weakness and faulty mechanics after anterior cruciate ligament reconstruction (ACLR). Clinical tests performed early in rehabilitation, which predict knee mechanics at return-to-sport, are virtually unknown and critically needed to guide clinical decision making. The purpose of this study is to determine if quadriceps strength, Y balance anterior (YB-A) reach distance, and single-leg step-down test performance (SLSD) conducted 3 months post-ACLR are predictive of knee flexion excursion (KFLEX) and knee extensor moment (KEM) during running 6 months post-ACLR.Thirty (16 females) subjects were collected 3 and 6 months post-ACLR. Age, 21.3 ± 7.6 yr; mass, 69.85 ± 11.4 kg; height, 1.73 ± 0.09 m. At 3 months post-ACLR, subjects performed isometric quadriceps strength testing, YB-A, and SLSD assessments. At 6 months post-ACLR, subjects underwent three-dimensional motion analysis while running on an instrumented treadmill. Pearson correlation coefficients and stepwise multiple regression were used to assess the relationships of 3-month and 6-month variables.Quadriceps strength (r = 0.493, P0.01), YB-A (r = 0.394, P = 0.03), and SLSD (r = 0.648, P0.01) were significantly correlated to KFLEX. Quadriceps strength (0.505, P0.01) and SLSD (.541, P0.01) were significantly correlated with KEM, whereas YB-A (.276, P = 0.06) was not. SLSD and quadriceps strength were predictive of KEM (adj R², 0.36; P = 0.001) whereas only SLSD was predictive of KFLEX (adj R², 0.40; P0.001).After ACLR, better performance in SLSD and quadriceps strength 3 months postsurgery is predictive of improved sagittal plane knee mechanics during running 6 months postsurgery.

Background: Rate of torque development (RTD) measures the ability of a muscle to produce torque quickly. Decreased quadriceps RTD may impair performance of sporting tasks after surgery. Currently, little is known about variations in quadriceps RTD between anterior cruciate ligament (ACL)–reconstructed and noninjured limbs. Purpose: To determine the differences in RTD of the quadriceps, the rate and timing of knee extensor moment (KEM) development, and knee flexion excursion during running after ACL reconstruction with patellar tendon autograft. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This study involved 21 patients (11 female) 6 months after ACL reconstruction with patellar tendon autograft (median [IQR]: age, 18 [16-20] years; mass, 68.18 [61.34-75] kg; height, 1.74 [1.66-1.78] m). Patients performed four 5-second maximal voluntary isometric strength trials of both limbs on an isokinetic dynamometer. RTD was calculated as the mean slope of the torque-time curve between 20% and 80% of total time to peak torque. Then, patients underwent 3-dimensional motion analysis while running on an instrumented treadmill at a self-selected running speed (mean ± SD, 2.68 ± 0.28 m/s). The rate of knee extensor moment (RKEM) was calculated as the mean slope of the moment curve between 10% and 30% of stance phase. Between-limb comparisons were determined with a paired t test for peak KEM, RKEM, knee flexion excursion during 10% to 30% of stance, and time to generate KEM. Results: In the reconstructed limb, deficits in the peak rate of quadriceps torque development compared with the noninjured limb existed both isometrically (RTD, 257.56 vs 569.11 Nm/s; P < .001) and dynamically (RKEM, 16.47 vs 22.38 Nm/kg·m·s; P < .001). The reconstructed limb also generated a KEM later in the stance phase compared with the noninjured limb (11.37% vs 9.61% stance; P < .001) and underwent less knee flexion excursion (15.5° vs 19.8°; P < .001). Conclusion: After ACL reconstruction with patellar tendon autograft, patients have lower RTD and RKEM in the reconstructed limb. Deviations in RTD and the timing of the KEM can change the way the knee is loaded and can potentially increase injury risk and future development of posttraumatic osteoarthritis. Rehabilitation should consider exercises designed to improve RTD and prepare the limb for the demands of sport performance.

Objectives: Currently, objective functional assessments are performed at the time of return to play following an anterior cruciate ligament (ACL) reconstruction. While informative, by that time the majority of organized rehabilitation has been completed, leaving little time for clinicians to address remaining impairments. Further, few objective tests have been compared to faulty movement mechanics. Identifying objective clinical tests that can be administered early during recovery from an ACL reconstruction which predict long term joint mechanics would provide sufficient time to address the underlying deficits prior to return to play testing. Thus, the purpose of this study was to determine if objective clinical tests (60 second single leg step down test and quadriceps strength) administered 3 months after surgery predicted jump landing mechanics of the knee (knee extension moment, average loading rate, vertical impact peak) at 6 months following an ACL reconstruction. Methods: 29 subjects completed objective clinical testing at 3 months post operatively that included the 60 second single leg step down test and an assessment of isometric knee strength. To perform the 60 second single leg step down test, subjects performed a single leg squat by touching their heel on a scale with less than 10% of their bodyweight as many times as they could for 60 seconds while standing on an 8-inch box. Isometric knee extension strength was assessed with a hand held dynamometer secured to a table. The subject performed 4 isometric maximum isometric contractions for 5 seconds. At 6 months, performed a instrumented drop vertical landing jumping. Three trials were taken and the data were analyzed using custom Labview and Visual 3D code. The average loading rate was defined as the linear portion of the vertical ground reaction curve between 20-80% of foot contact to initial impact peak. Associations between quadriceps strength and the timed single leg step down test to knee extensor moment, average loading rate, and vertical impact peak were then made with Pearson correlation coefficients. Results: 29 subjects (15 male and 14 female, Ages 20.2 ± 4.7 yrs, 24 bone patellar bone vs 5 hamstring autografts, H 1.75 ± 0.12 m, M 72.2 ± 12.1 kg) completed the study. The mean quadriceps strength was 23.3 ± 10.2 N, timed single leg step down test 20 ± 11 step downs, knee extensor moment 1.32 ± 0.54 Nm/kg, loading rate was 64.5 ± 23.6 %bodyweight/sec, and vertical impact peak 0.97 ± 0.36 %bodyweight. We found significant positive associations between 3 month quadriceps strength and knee extensor moment (r=0.442, p=0.016), average vertical loading rate (r=0.426, p=0.021), and vertical impact peak (r=0.619, p=0.000) (Figure 1). We found no significant associations between 3 month single leg step down performance and landing mechanics. Conclusion: We show the ability of a early, quick, clinically-feasible method of assessing quadriceps strength to predict joint mechanics during a drop vertical jump 6 months after ACL reconstruction. This assessment can be used to screen individuals at much earlier time point who need additional focused treatment to improve their outcomes prior to return to play testing. Further, they can give the orthopedic surgeon additional data to educate the patient and family about the need to not return to higher level activities too early and reinforces the need to be compliant with rehabilitation in order to maximize results at the time individuals begin return to sport drills.

Objectives: The effect of kinesiophobia (fear of movement) following an anterior cruciate ligament (ACL) reconstruction has recently received greater attention. Elevated kinesiophobia as measured on the Tampa Scale of Kinesiophobia (TSK) has been previously found to be associated with poorer outcomes. However, the effect of kinesiophobia in ACL reconstructed patients on high impact and challenging tasks associated with re injury risk such as jumping has not been investigated. Establishing the relationship between kinesiophobia and jump landing mechanics could result in the development of specific treatments to reduce fear of movement and improve jump landing mechanics after ACL reconstruction, resulting in a diminished re-injury risk. Therefore, the purpose of this study is to define the relationship between landing mechanics (axial loading rates and impact forces) with the TSK score in patients 6 months after ACL reconstruction. Methods: Twenty subjects, 6 months post ACL reconstruction, who had completed post-operative physical therapy, and were cleared by their physician to begin return to sport drills participated in the study. Subjects completed an instrumented drop vertical landing assessment with the ground reaction forces recorded while the subjects performed a drop vertical jump task off a 30.48 cm high box. Three trials were taken and the data were analyzed using custom Labview code and Visual 3D software during the period of time from foot contact until initial impact peak. The average loading rate was defined as the linear portion of the vertical ground reaction curve between 20-80% of foot contact to initial impact peak. Subjects also completed the TSK questionnaire. Associations between loading rate and vertical impact peak to the TSK scale were made with Pearson correlation coefficients with significant relationships defined as pResults: 20 subjects (11 female, 9 male, Ages 19 ± 3.3 yrs, H 1.73 ± 0.11 m, M 69.1 ± 12.2 kg) with bone patellar bone autografts completed the study. The mean loading rate was 56.96 ± 18.6 %bodyweight/sec, initial impact peak 0.88 ± 0.24 %bodyweight, and TSK value was 33.1 ± 6.8. There was a significant negative association between poorer responses on the TSK scale and initial impact peak forces (r=-0.624, p=0.003) but not average loading rate (r=-0.243, p=-0.302) (Figure 1). Conclusion: We found greater kinesiophobia to be associated with a lower weight-bearing in the ACL reconstructed limb. Potentially, subjects who are afraid of loading their reconstructed limb transfer weight to the uninjured limb, increasing the demand placed upon that limb. The greater forces that the contra lateral limb must absorb may in part be related to the elevated risk of injury associated with the non injured limb. The lack of relationship to loading rate suggests kinesiophobia is more related to the magnitude of the load and not the subject’s ability to control the load. These results suggest that in patients with elevated kinesiophobia, cognitive training may be needed before initiating movement retraining or other exercises to improve landing mechanics. Additional prospective studies are needed to assess if these relationships improve over time and determine the optimal time to intervene to reduce subsequent injury risk.

Histologic and immunostaining analyses were performed on articular cartilage/subchondral bone biopsy specimens overlying MRI-detected bone bruises in 12 patients with anterior cruciate ligament (ACL) tears. Staining with toluidine blue for proteoglycan revealed loss of staining from the superficial portion of the articular cartilage. Immunostaining for cartilage oligomeric matrix protein (COMP) showed an increased staining in the superficial matrix of the articular cartilage. Using polyclonal antisera against COMP, the authors performed a competitive enzyme-linked immunosorbent assay (ELISA) on the synovial fluid from the injured and uninjured knees. There was an approximately 10-fold higher synovial fluid COMP levels in injured knees. The COMP levels were greater in those patients who had synovial fluid samples harvested closer to the date of initial injury. Western blot analysis of the synovial fluid showed an increased presence of COMP degradation fragments from injured knees. These results are indicative of a significant injury to the articular cartilage, and may represent preclinical posttraumatic osteoarthritic lesions.

Objectives: We sought to determine the overall return to play (RTP) rate of female collegiate soccer athletes after anterior cruciate ligament (ACL) reconstruction in the Southeastern Conference (SEC). Additionally, we examined particular athlete related and surgical technique related variables as they correlated to RTP. We hypothesized that RTP after ACL reconstruction would be higher than previously published results and that it would be independent of graft type utilization or surgical techniques employed. Methods: Head team physicians and athletic training staff of the 14 institutions of the SEC were contacted to request participation in the study. All institutions were sent information regarding the nature of the study, a standardized spreadsheet with standardized response choices for the purpose of data collection from the participating institutions, and instructions regarding athlete inclusion criteria. The spreadsheet provided queried certain athlete and technical surgical related variables for ACL reconstructions performed at the participating institutions over the previous 8 years (2005-2013). Results: All 14 of the SEC institutions chose to participate and provided data. 79 reconstructions were reported with RTP data available for 78 women soccer athletes. Overall RTP rate was 84.6%. There was statistical significance in RTP rates favoring athletes in earlier years of eligibility versus later years (pConclusion: Of Division I collegiate women soccer athletes undergoing ACL reconstruction, overall RTP rate approaches 85%. Undergoing ACL reconstruction earlier in the college career before the 4th year of eligibility as well as the presence of a scholarship had a positive effect on RTP. Surgical factors including graft type, fixation methods, tunnel placement technique, concomitant knee surgery, and revision status played showed no significant effect on RTP rate.

This retrospective study assessed 5 male and 5 female patients, age 35.1+/-16 years, height 171.8+/-12 cm, and weight 75.5+/-18 kg (mean+/-SD) who were more than 1 year post isolated tibial fracture (18+/-6 months) and had been treated with an intramedullary tibial nail. Subjects completed a 12-question visual analog scale, a physical symptom and activity of daily living survey, and were also tested for bilateral isokinetic (60 degrees/s) quadriceps femoris and hamstring strength. Knee pain during activity, stiffness, swelling, and buckling were the primary symptomatic complaints. Perceived functional task deficits were greatest for climbing or descending stairs, pivoting, squatting, and walking on uneven surfaces. Involved lower extremity knee extensor and flexor torque production deficits were 25% and 17%, respectively. Early rehabilitation focuses on maintaining adequate operative site bony fixation while providing controlled, progressive, and regular biomechanical loading to restore functionally competent tissue. Following adequate fracture healing, greater emphasis should be placed on lower extremity functional recovery including commonly performed activities of daily living and other functional tasks that are relevant to the patient's disability level. A cyclic rehabilitation program that progresses the weight-bearing environment to facilitate bone and soft tissue healing and neuromuscular re-education is proposed.