This study aimed to determine the incidence of meniscal tears and describe the tear morphology and selected treatment in patients undergoing anterior cruciate ligament (ACL) reconstruction. We also will discuss the potential market for future tissue engineering aimed at preserving meniscal function. A multicenter cohort of 1014 patients undergoing ACL reconstruction between January 2002 and December 2003 was evaluated. Data on patient demographics, presence of a meniscus tear at time of ACL reconstruction, tear morphology, and meniscal treatment were collected prospectively. Meniscal tears were categorized into 3 potential tissue engineering treatment strategies: all-biologic repair, advanced repair, and scaffold replacement. Of the knees, 36% had medial meniscal tears and 44% had lateral meniscal tears. Longitudinal tears were the most common tear morphology. The most frequent treatment method was partial meniscectomy. Thirty percent of medial meniscal tears and 10% of lateral meniscal tears are eligible for all-biologic repair; 35% of medial meniscal tears and 35% of lateral meniscal tears are eligible for an advanced repair technique; and 35% of medial meniscal tears and 55% of lateral meniscal tears are eligible for scaffold replacement. Although meniscal preservation is generally accepted in the treatment of meniscal tears, most tears in this cohort were not repairable, despite contemporary methods. The results of this cohort will hopefully stimulate and focus future research and development of new tissue engineering strategies for meniscus repair.

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

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (~10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as a function of the combined 6 DOF knee loads. Following individual model verifications, generalized gender-specific models were generated and subjected to 6 DOF external load scenarios consistent with both a clinical examination and a dynamic sports maneuver. The ensuing model-based strain predictions were subsequently examined for gender-based discrepancies. Male and female specimen-specific models predicted ACL strain within 0.51%+/-0.10% and 0.52%+/-0.07% of the measured data respectively, and explained more than 75% of the associated variance in each case. Predicted female ACL strains were also significantly larger than respective male values for both simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities.

Anterior cruciate ligament (ACL) reconstruction is a common surgical knee procedure that requires intensive postoperative rehabilitation by the patient. A variety of randomized controlled trials have investigated aspects of ACL reconstruction rehabilitation. A systematic review of English language level 1 and 2 studies identified 54 appropriate randomized controlled trials of ACL rehabilitation. This part of the article discusses open versus closed kinetic chain exercises, neuromuscular electrical stimulation, accelerated rehabilitation, and miscellaneous topics.

Anterior cruciate ligament (ACL) reconstruction is a common surgical knee procedure that requires intensive postoperative rehabilitation by the patient. A variety of randomized controlled trials have investigated aspects of ACL reconstruction rehabilitation. A systematic review of English language level 1 and 2 studies identified 54 appropriate randomized controlled trials of ACL rehabilitation. Topics discussed in this part of the article include continuous passive motion, early weight bearing in motion, postoperative bracing, and home-based rehabilitation.

This review presents objective data, as far as possible, about the current understanding of the biomechanics of the patellofemoral joint as it pertains to the management of patellofemoral problems. When faced with a patellofemoral malfunction, it is important to check all the soft-tissue and articular geometry factors relating to the patella locally and not to neglect the overall lower limb alignment and function. It is important to remember that small alterations in alignment can result in significant alterations in patellofemoral joint stresses and that changes in the mechanics of the patellofemoral joint can also result in changes in the tibiofemoral compartments. Surgical intervention for patellofemoral problems needs to be planned carefully and take into account an individual's anatomy.

BACKGROUND: The risk of tear of the intact anterior cruciate ligament in the contralateral knee after anterior cruciate ligament reconstruction of the opposite knee and the incidence of rupturing the anterior cruciate ligament graft during the first 2 years after surgery have not been extensively studied in a prospective manner. Clinicians have hypothesized that the opposite normal knee is at equal or increased risk compared with the risk of anterior cruciate ligament graft rupture in the operated knee. HYPOTHESIS: The risk of anterior cruciate ligament graft rupture and contralateral normal knee anterior cruciate ligament rupture at 2-year follow-up is equal. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The Multicenter Orthopaedic Outcome Network (MOON) database of a prospective longitudinal cohort of anterior cruciate ligament reconstructions was used to determine the number of anterior cruciate ligament graft ruptures and tears of the intact anterior cruciate ligament in the contralateral knee at 2-year follow-up. Two-year follow-up consisted of a phone interview and review of operative reports. RESULTS: Two-year data were obtained for 235 of 273 patients (86%). There were 14 ligament disruptions. Of these, 7 were tears of the intact anterior cruciate ligament in the contralateral knee (3.0%) and 7 were anterior cruciate ligament graft failures (3.0%). CONCLUSION: The contralateral normal knee anterior cruciate ligament is at a similar risk of anterior cruciate ligament tear (3.0%) as the anterior cruciate ligament graft after primary anterior cruciate ligament reconstruction (3.0%).

BACKGROUND: Acute and chronic cartilage injury of the knee has an important impact on prognosis. The validity of the classification of such injuries is critical for prospective multicenter studies. The agreement among multiple surgeons at different institutions for articular cartilage lesions has not been established. HYPOTHESIS: Arthroscopic classification of articular cartilage lesions is reliable and reproducible and can be used for multicenter studies involving multiple surgeons. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 1. METHODS: A total of 6 surgeons from 5 centers reviewed 31 videos of articular cartilage lesions. With grade 2 and grade 3 combined for the analysis, observed agreement ranged from 81% to 94%, and kappa ranged from 0.34 to 0.87. An additional 22 videos comprising grade 2 and grade 3 lesions were analyzed, and the observed agreement was 80%, with an overall kappa of 0.47. CONCLUSION: Arthroscopic grading of articular cartilage lesions is reproducible among surgeons at different centers. CLINICAL RELEVANCE: Articular cartilage lesions can be reliably classified among surgeons at different sites. Such reliability is important for multicenter clinical research studies involving arthroscopic knee surgery.