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Background: The incidence of subsequent posttraumatic osteoarthritis (OA) diagnosis after surgery and the associated risk factors have been well reported after single-ligament anterior cruciate ligament (ACL) reconstruction; however, to date, the incidence of posttraumatic OA for those who have experienced multiligament knee injury (MLKI) has been reported only in relatively small, single-center studies. Purpose: To compare the incidence of OA diagnoses between patients with ACL injury versus patients with MLKI and to identify risk factors for OA diagnosis after MLKI. Study Design: Cohort study; Level of evidence, 3. Methods: This study used the PearlDiver Mariner database, which contains insurance claims information on >151 million orthopaedic patients. We identified 2 cohorts for this study by using Current Procedural Terminology codes. The cohorts included patients between the ages of 16 and 60 who underwent either isolated ACL reconstruction (n = 114,282) or MLKI reconstruction (n = 3325) between July 1, 2010, and August 30, 2016. MLKI reconstruction was operationally defined as ACL reconstruction plus concurrent surgical treatment of ≥1 additional ligaments. Demographic factors, concomitant meniscal and cartilage procedures, and subsequent reoperation to restore motion were recorded, as was the incidence of knee OA diagnosis within 5 years of the index surgical procedure. OA incidence and demographic and surgical factors were compared (1) between ACL and MLKI groups and (2) between patients with MLKI either with or without OA diagnosis. Results: A significantly greater proportion of patients with MLKI were diagnosed with knee OA within 5 years of surgery (MLKI = 299/3325 [9.0%] vs ACL = 6955/114,282 [6.1%]; P < .0001) (odds ratio [OR], 1.52; 95% CI, 1.35-1.72; P < .001). Factors associated with increased odds of OA diagnosis after MLKI included age ≥30 years (OR, 5.90), reoperation to restore motion (OR, 2.54), obesity (OR, 1.96), mood disorder diagnoses (OR, 1.85), partial meniscectomy (OR, 1.85), and tobacco use (OR, 1.72). Concomitant meniscal repair was protective against OA diagnosis (OR, 0.06). Conclusion: OA incidence was greater after MLKI reconstruction than after isolated ACL reconstruction. Potentially modifiable risk factors for OA after MLKI were identified and include obesity, tobacco use, depression, and the need for motion-restoring surgery.

Background: Anterior cruciate ligament (ACL) tear (ACLT) leads to protracted quadriceps muscle atrophy. Protein turnover largely dictates muscle size and is highly responsive to injury and loading. Regulation of quadriceps molecular protein synthetic machinery after ACLT has largely been unexplored, limiting development of targeted therapies. Purpose: To define the effect of ACLT on (1) the activation of protein synthetic and catabolic signaling within quadriceps biopsy specimens from human participants and (2) the time course of alterations to protein synthesis and its molecular regulation in a mouse ACL injury model. Study Design: Descriptive laboratory study. Methods: Muscle biopsy specimens were obtained from the ACL-injured and noninjured vastus lateralis of young adult humans after an overnight fast (N = 21; mean ± SD, 19 ± 5 years). Mice had their limbs assigned to ACLT or control, and whole quadriceps were collected 6 hours or 1, 3, or 7 days after injury with puromycin injected before tissue collection for assessment of relative protein synthesis. Muscle fiber size and expression and phosphorylation of protein anabolic and catabolic signaling proteins were assessed at the protein and transcript levels (RNA sequencing). Results: Human quadriceps showed reduced phosphorylation of ribosomal protein S6 (–41%) in the ACL-injured limb ( P = .008), in addition to elevated phosphorylation of eukaryotic initiation factor 2α (+98%; P = .006), indicative of depressed protein anabolic signaling in the injured limb. No differences in E3 ubiquitin ligase expression were noted. Protein synthesis was lower at 1 day ( P = .01 vs control limb) and 3 days ( P = .002 vs control limb) after ACLT in mice. Pathway analyses revealed shared molecular alterations between human and mouse quadriceps after ACLT. Conclusion: (1) Global protein synthesis and anabolic signaling deficits occur in the quadriceps in response to ACL injury, without notable changes in measured markers of muscle protein catabolism. (2) Importantly, these deficits occur before the onset of significant atrophy, underscoring the need for early intervention. Clinical Relevance: These findings suggest that blunted protein anabolism as opposed to increased catabolism likely mediates quadriceps atrophy after ACL injury. Thus, future interventions should aim to restore muscle protein anabolism rapidly after ACLT.

Objectives The National Football League (NFL) altered the 2020 season due to the COVID-19 pandemic, which resulted in cancelled preseason games and a dynamic regular season schedule to accommodate for cancelled games. The purpose of this study was to evaluate if the disrupted training and preseason schedule lead to increased injury rates as seen in other professional sports. We hypothesized that the overall injury rate would be higher in the 2020 season compared to the 2018-2019 seasons, and that this increase will affect all body regions equally. Methods : Publicly released NFL weekly injury reports were queried to identify players listed as out or placed on the injured reserve for at least one game in the 2018-2020 seasons. Injuries were categorized into upper extremity, lower extremity, spine/core, head, illness, not injury related and undisclosed injuries. Incidence per 1000 athlete exposures was calculated for the prior two seasons (2018-2019) and for the 2020 season separately. Percentage of injuries occurring in each position were calculated separately for the pre-COVID-19 (2018 and 2019) and post-COVID-19 (2020) cohorts. Incidence rate ratios (IRR) and confidence intervals were used to compare injury rates in 2018-2019 versus 2020. The z-test for proportions was used to determine significant differences between injury incidences. Results : The overall incidence rate per 1000 athlete exposures in 2020 was not significantly different compared to pre-COVID-19 seasons (21.6 versus 23.1, IRR 0.94, 95% CI: 0.9-1.0 p>0.999). The proportion of injuries by position did not change before and after COVID-19 either (p>0.999). Out listings due to illness were significantly increased during the 2020 season (0.8 versus 0.3, IRR 2.8, 95% CI: 1.4-5.2, p=0.004). Conclusion The incidence of NFL injuries did not significantly change in 2020. The distribution of injuries did not change with respect to position.

Background: In the skeletally mature anterior cruciate ligament (ACL) reconstruction population, patients aged Purpose: To examine the incidence of ipsilateral graft failure and contralateral ACL injury in the skeletally immature patient population. Study Design: Systematic review and meta-analysis. Methods: Using the PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines, we reviewed all literature that involved ACL reconstruction performed on skeletally immature patients between May 1976 and May 2019. Patient demographics, surgical technique, and the prevalence of ipsilateral graft failure or subsequent contralateral ACL injury were recorded. Ipsilateral, contralateral, and secondary ACL injuries were then compared between sexes via chi-square tests. Results: A total of 24 articles (1254 children; 1258 knees) met inclusion criteria for analysis. Ipsilateral graft failures occurred in 105 of 1258 patients (8.3%), and there were no statistically significant sex differences in the prevalence of graft failures (female, 9.7%; male patients, 7.1%; P = .14). The prevalence of contralateral ACL injury was significantly greater in female (29/129; 22.5%) than male (18/206; 8.7%; P = .0004) patients in the 9 studies that reported contralateral injury. Skeletally immature female patients were at significantly increased risk of contralateral ACL injury (odds ratio = 3.0; P = .0006) when compared with their male counterparts. Conclusion: In the literature to date, 1 in 3 female skeletally immature patients experienced an ipsilateral graft failure or contralateral ACL injury. Regardless of sex, the 24% prevalence of secondary injury after pediatric ACL reconstruction is almost identical to previously published secondary injury rates in skeletally mature patients

OBJECTIVE To determine the relationship between patient-reported outcomes (PROs) to the single-leg step-down test (SLSD) and the Y-balance anterior reach (YB-A) 6 months after primary anterior cruciate ligament reconstruction (ACLR). DESIGN Cross-sectional. SETTING Laboratory. PARTICIPANTS Sixty-six patients 6 months after ACLR participated. INTERVENTIONS Patients performed the SLSD, YB-A, and completed PROs after ACLR. MAIN OUTCOME MEASURES Patients completed the International Knee Documentation Committee Score (IKDC), the Lysholm Activity Scale, the Tampa Scale of Kinesiophobia (TSK-11), and the Knee Injury and Osteoarthritis Outcome Score (KOOS)-Symptom, -Sport, and -Quality of Life (QOL) subscales. The SLSD requires subjects to complete as many single-leg step-downs as possible in 60 seconds, and the YB-A involves reaching anteriorly on a single limb. Pearson product moment correlations were used to assess relationships between the YB-A and SLSD performance to each PRO. RESULTS Single-leg step-down test symmetry was significantly correlated with the TSK-11 (r = -0.70), KOOS-Sport (r = 0.40), -Symptom (r = 0.46), and -QOL (r = 0.42). The YB-A symmetry was significantly correlated with the KOOS-Symptom (r = 0.30) and KOOS-Sport (r = 0.30). CONCLUSIONS Single-leg step-down test performance demonstrated stronger relationships to patient-reported knee function than the YB-A. Furthermore, the SLSD symmetry was strongly correlated with fear of movement. The SLSD provides a robust method for clinicians to assess dynamic knee function and may aid in identifying patients who could benefit from intervention to reduce fear of movement or reinjury.

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.

The rates of arthroscopic meniscus repair continue to increase with excellent reported outcomes. Complications, sometimes catastrophic, following meniscus repair may occur. The rate of postoperative complications may be reduced by adequate diagnosis, appropriate patient selection, meniscus repair selection, surgical techniques, and postoperative management. When complications occur, the provider must identify and take steps to rectify as well as prevent further complications from occurring. The purpose of this article is to detail the common diagnostic, technical, and postoperative pitfalls that may result in poor patient outcomes.

There has been an increasing awareness of the importance of the meniscus in maintaining the health and function of the knee. When injured, magnetic resonance imaging (MRI) has become the gold standard to diagnose meniscal tears. The information obtained from the MRI helps determine the need for surgical intervention. To achieve the best patient outcome a surgeon must be able to diagnose a meniscal injury by MRI as well as identify the injury at time of arthroscopy. This article aims to illustrate meniscal pathology utilizing side by side comparison of MRI identified meniscal injuries to its arthroscopic correlate as well as describe treatment options for the injury.

Anterior cruciate ligament (ACL) ruptures are some of the most common sports-related injuries. Treatment of these injuries with ACL reconstruction has evolved over the last several decades. Anatomic single-bundle ACL reconstruction offers an accurate and reproducible method to reproduce native knee anatomy, restore knee kinematics, and ultimately restore function and decrease long-term degenerative effects. The importance of adequate arthroscopic visualization and a thorough understanding of the native anatomic ACL landmarks are discussed in this article. Furthermore, surgical technique, pearls, pitfalls, potential complications, rehabilitation, and outcomes are reviewed.

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: 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.

Background: Recent data from the Danish anterior cruciate ligament (ACL) registry demonstrated increased reoperation rates for hamstring tendon autografts when an anatomic ACL reconstruction is performed. This is consistent with reports of greater time needed for hamstring tendon autografts to mature compared with other autografts. Purpose: To review the literature comparing graft failure rate between patellar and hamstring tendon autografts placed anatomically and to determine if there are differences in return to preinjury activity levels between autografts. Study Design: Systematic review with meta-analysis and meta-regression. Methods: The PubMed, MEDLINE, SPORTDiscus, and CINAHL databases were used to identify studies published from January 1, 2000, through March 7, 2014. To compare postoperative outcomes between patellar tendon and hamstring tendon autografts, summary event rates for graft failure and return to preinjury activity level were calculated. A meta-analysis was performed to calculate a summary odds ratio (OR) for graft failure between autografts using the studies that directly compared the 2 autografts. Meta-regression analyses were performed to assess the influence of postoperative follow-up time on graft failure rate. Results: A total of 28 studies reported graft failures for patellar tendon (6 studies) and hamstring tendon (26 studies) autografts used with anatomic ACL reconstruction; 4 of the 28 were comparison studies. Graft failure rate was not significantly different between patellar tendon (7.0% [95% CI, 4.6%-10.5%]) and hamstring tendon autografts (3.9% [95% CI, 2.7%-5.6%]). The odds of graft failure were slightly higher for hamstring tendon autografts (OR, 1.21 [95% CI, 0.63-2.33]), but this difference was not significant ( P = .57). The rate of patients returning to preinjury activity levels was not significantly different between patellar (n = 1 study; 58.1% [95% CI, 40.4%-73.9%]) and hamstring tendon autografts (n = 5 studies; 75.6% [95% CI, 43.7%-92.5%]). Overall graft failure rate was positively associated with postoperative follow-up time, but this effect was only significant with hamstring tendon autografts ( P < .05). Conclusion: Differences in graft failure rate between patellar tendon and hamstring tendon autografts were not significant. Although follow-up time was only found to have a significant influence on hamstring tendon graft failure rates, this was likely due to the smaller sample of studies assessing patellar tendon graft failures. Differences in return to preinjury activity levels could not be determined due to the lack of studies assessing that outcome. Both patellar and hamstring tendon autografts demonstrate a low risk of failure and moderately high return to activity level after anatomic ACL reconstruction.

Meniscal injuries are common in young physically active individuals, particularly those who are involved in contact level 1 sports that involve frequent pivoting, such as soccer and American football. This is a unique population because of their high physical activity at a young age, and it is important that correct diagnosis and appropriate treatment are provided, as the medial and lateral menisci are essential for normal knee function. In this article, we review the anatomy and function of the meniscus, the epidemiology of meniscal tears, and mechanism(s) of injury. Important concomitant injuries are also discussed. When making a diagnosis, relevant patient history, physical examination, and appropriate imaging studies are required. Nonoperative treatment is rarely successful for treating meniscal tears in young athletes, and therefore repair of the torn menisci is often required. We also discuss partial resection (which should only be performed when repair is not possible), as well as rehabilitation protocols after repair has been performed. All of these factors associated with meniscal injuries are important for a physician when diagnosing and treating these often complex injuries.

Anterior cruciate ligament (ACL) injuries are common in athletic and physically active populations, and can result in significant functional disability. Female athletes in particular have been found to be at a relatively high risk for noncontact ACL injuries. Many risk factors, both intrinsic and extrinsic, have been identified. Although some individuals may be treated nonoperatively with an aggressive rehabilitation program, athletes desiring to return to physical activities that require use of the ACL need surgical reconstruction. Surgical techniques remain controversial in regard to tunnel placement and optimal graft choices. Recent literature advocates a more oblique ACL reconstruction to more closely recreate normal knee kinematics and eliminate pathologic rotational laxity. A supervised and intensive rehabilitation program is necessary to achieve desired results. Anatomic and neuromuscular risk factors, often gender related, are the focus of most ACL injury prevention programs.

Anterior cruciate ligament (ACL) injuries are common in the athletic population. In fact, ACL reconstruction has become one of the most common orthopedic procedures with over 100,000 being performed annually. As the number of primary ACL reconstructions continues to increase, so will the need for revision surgery. The causes of failure are numerous and multifactorial. However, understanding the exact cause of failure before undertaking a revision ACL surgery is paramount in providing the patient with a successful outcome. It is our belief that anatomic restoration of ACL anatomy in the revision setting is best accomplished using the double-bundle technique in the majority of cases. This is a technically demanding procedure that requires proper preoperative preparation. This article outlines our approach to these challenging situations.

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 Evaluate the relationship of hip and trunk muscle function with the Single Leg Step-Down test (SLSD). Study design Laboratory study. Setting Biomechanics Laboratory. Participants 71 healthy participants with no history of anterior cruciate ligament (ACL) or lower extremity injury in the last 3 months completed this study (38 males, 33 females; mean 25.49 ± 0.62 years). Main outcomes Hip abduction (HABD), external rotation (HER), and extension (HEXT) peak isometric force were measured. Trunk endurance was measured with plank (PL) and side plank (SPL) tests. SLSD repetitions in 60-s and dynamic knee valgus (VAL) were recorded. Results PL, SPL, HABD, HER, and HEXT were positively correlated with SLSD repetitions. PL ( r = 0.598, p p = 0.001, R 2 = 0.469) was a predictor of SLSD repetitions. VAL trended toward negative correlation with PL and SPL. Sex-specific differences were present, with PL, SPL, HABD, and HER showing stronger relationships with SLSD in females. Conclusion Hip and trunk muscle function were positively correlated with SLSD performance, and these relationships were strongest in females. PL predicted performance on the SLSD. Further research is needed to investigate the utility of SLSD as a screening or return-to-play test for lower extremity conditions such as ACL injury and patellofemoral pain.

SUMMARY Middle age patients who have failed anterior cruciate reconstruction and develop osteoarthritis present a significant challenge in orthopedic surgery. A clear understanding of the patient's symptoms must be obtained. Patients being considered for revision surgery should be well motivated, demonstrate increased anterior laxity on physical examination, and suffer from instability with activities of daily living. The etiology of failure can be established by a thorough history and physical examination, as well as appropriate radiologic studies. Poor outcome following ACL reconstruction may be caused by loss of motion, extensor mechanism dysfunction, arthritis or graft failure. The most common errors in surgical technique leading to recurrent laxity are nonanatomic tunnel position and failure to address associated instabilities. Technically successful revision depends on appropriate graft selection, hardware removal, anatomic tunnel positioning and correction of associated instabilities and skeletal malalignment. Results of revision ACL surgery may be inferior to those of primary reconstruction. The outcome is largely dependent on the integrity of the meniscal and articular cartilage. In the middle age patient with osteoarthritis of the knee, revision ACL surgery should be considered a salvage procedure whose primary goal is restoration of stability with activities of daily living.

Initial tibial fixation strength is the weak link after anterior cruciate ligament reconstruction with a quadrupled hamstring tendon graft fixed with bioabsorbable interference screws. The purpose of this study was to determine the biomechanical differences between 28-mm and tapered 35-mm interference screws for tibial fixation of a soft tissue graft in 16 young cadaveric tibias. Failure mode, displacement before failure, and ultimate failure load were tested with a testing machine aligned with the tibial tunnel to simulate a worst-case scenario. The mode of failure was graft slippage past the screw in all but one of the specimens. The mean maximum load at failure of the 28-mm screw was 594.9 ± 141.0 N, with mean displacement at failure of 10.97 ± 2.20 mm. The mean maximum load at failure of the 35-mm screw was 824.9 ± 124.3 N, with a mean displacement to failure of 14.38 ± 2.15 mm. The 38% difference in mean maximal load at failure was significant. Important variables in hamstring tendon graft fixation within a bone tunnel include bone mineral density, dilatation, gap size, screw placement, and screw width and length. Attention to these variables will help to provide secure graft fixation during biologic incorporation throughout the rehabilitation period.

The traumatically dislocated knee can be a devastating injury; fortunately, it is uncommon. More attention is being given to the treatment of knee dislocations as the capability of ligamentous reconstruction increases. Great treatment advances are anticipated as this interest grows and outcomes are evaluated. Nonetheless, the complications of this injury, including loss of limb, still occur from the missed diagnosis of a knee dislocation. MR imaging and other technological advances do not relieve the clinician of the responsibility for performing a thorough physical examination. Suspicion of an associated neurovascular injury must always be high. To a certain degree, prevention of this injury may be possible in the high-velocity accidents that occur with motor vehicles and in industry. Advancement in vehicular designs, with specific attention to airbags, dashboards, and firewalls, needs to be made to reduce the incidence and magnitude of lower extremity trauma in motor vehicle accidents. Seat belts remain the most effective restraint in the prevention of lower extremity trauma in the motor vehicle.

Cruciate ligament reconstruction has progressed dramatically in the last 20 years. Anatomic placement of ligament substitutes has fostered rehabilitation efforts that stress immediate and full range of motion, immediate weightbearing, neuromuscular strength and coordination, and early return to athletic competition (3 months). This has placed extreme importance on secure graft fixation at the time of ligament reconstruction. Current ligament substitutes require a bony or soft tissue component to be fixed within a bone tunnel or on the periosteum at a distance from the normal ligament attachment site. Fixation devices have progressed from metal to biodegradable and from far to near-normal native ligament attachment sites. Ideally, the biomechanical properties of the entire graft construct would approach those of the native ligament and facilitate biologic incorporation of the graft. Fixation should be done at the normal anatomic attachment site of the native ligament (aperture fixation) and, over time, allow the biologic return of the histologic transition zone from ligament to fibrocartilage, to calcified fibrocartilage, to bone. The purpose of this article is to review current fixation devices and techniques in cruciate ligament surgery.

We prospectively evaluated 40 patients who had knee inflammation after isolated anterior cruciate ligament rupture with or without an associated “geographic” bone bruise/subchondral fracture of the lateral femoral condyle. All patients with acute ruptures documented by magnetic resonance imaging within 1 week of injury were evaluated for a geographic bone bruise/subchondral fracture of the lateral femoral condyle. Two groups of 20 patients each (bone bruise versus no bone bruise) were then enrolled. Variables measured at 1, 2, 3, and 4 weeks after injury included pain, range of motion, effusion, and number of days with an antalgic gait. Patients with a bone bruise had increased size and duration of effusion, increased number of days required to nonantalgic gait without external aids, increased days to achieve normal range of motion, and increased pain scores at measured time intervals. This study confirms results of previous clinical and histologic studies showing an associated articular cartilage lesion, otherwise known as bone bruise/subchondral fracture, is clinically significant. There appears to be an association between a geographic bone bruise and increased disability in patients with acute anterior cruciate ligament ruptures. Patients with a geographic bone bruise may require longer to reach normal homeostasis (range of motion, pain, neuromuscular control) before undergoing anterior cruciate ligament reconstruction.

Single group, post-test design using the uninvolved lower extremity as the experimental control.To determine relationships between ankle swelling and flexor digitorum longus and peroneus longus H-reflex amplitude and latency.Primary capsuloligamentous injury, neural injury, and joint effusion and swelling may contribute to H-reflex changes following inversion ankle sprain. The relationship between ankle swelling and invertor or evertor H-reflexes has not been reported.Fifteen subjects with acute grade I or II inversion ankle sprains (mean +/- SD) 6.5 +/- 3 days after onset participated in this study. Swelling was estimated using a tape measure and the figure-of-eight girth assessment method. H-reflexes were determined using standard techniques. Paired t-tests were used to compare mean differences in ankle girth (swelling) and ankle invertor or evertor H-reflex amplitude and latency between the involved and uninvolved limbs. Pearson product moment correlations were used to assess relationships between swelling and H-reflex variables.Involved limb ankle girth was increased with respect to the uninvolved limb (1.5 +/- 0.9 cm) and the involved ankle flexor digitorum longus latency was delayed (0.72 +/- 0.7 ms). There was a moderate positive association (r = 0.73) between the latency delay in the involved ankle flexor digitorum longus and swelling. There were no significant differences in H-reflex amplitude and peroneus longus latency between ankles.Grade I or II inversion sprains and the related swelling appear to delay involved ankle flexor digitorum longus latency to a greater extent than peroneus longus latency. Clinicians need to direct greater attention to the ankle invertors when designing and implementing ankle rehabilitation programs, particularly during the swelling management phase of treatment.