Anatomical evaluation of the superficial medial collateral ligament distal tibial attachment of the knee.

This study aimed to evaluate the superficial medial collateral ligament distal tibial attachment (sMCL-dTA) morphologically and morphometrically. Seventeen unpaired formalin-fixed cadaveric knees were used. The sMCL was divided into anterior and posterior sections in the paracoronal plane along the midline of the sMCL. The distance from the medial edge of the tibial plateau and the joint line to the proximal margin, center, and distal margin of the sMCL-dTA and the length of the sMCL-dTA were measured in the anterior section, respectively. The sMCL-dTA was histologically observed in the posterior section with hematoxylin and eosin and Masson's trichrome staining. The distance from the medial edge of the tibial plateauto the proximal margin, center, and distal margin of the sMCL-dTA were 38.1 ± 4.2, 49.7 ± 4.4, and 61.5 ± 5.1 mm, respectively. The perpendicular distance from the joint line to the proximal margin, center, and distal margin of the sMCL-dTA were 36.1 ± 4.0, 47.4 ± 4.2, and 59.1 ± 4.8 mm, respectively. The length of the sMCL-dTA was 23.6 ± 3.2 mm. Histologically, the sMCL-dTA was formed by two layers of collagen fibers: the unidirectional fibrous layer and the multidirectional fibrous layer. The respective thicknesses of the two layers both decreased distally. The anatomical location, the length, and the attachment morphology of sMCL-dTA have been clarified using human cadaveric knees. Anatomical data in the present study contribute to the quality of surgery associated with sMCL-dTA.

Knee extension deficit during gait and knee extensor weakness persisting after saucerization and repair of discoid lateral meniscus tears.

BACKGROUND: Physical function and knee kinematics recovery after discoid lateral meniscus (DLM) tear surgery are essential for a better prognosis. However, these alterations remain unclear. Therefore, this study aimed to investigate changes in physical function and knee kinematics following saucerization and DLM tear repair. METHODS: We enrolled 16 patients who underwent saucerization and DLM tear repair. Postoperative changes in knee kinematics during gait, and physical function, were evaluated at 3, 6, and 12 months. RESULTS: The peak flexion angle of the operated limb during weight acceptance was significantly higher than that of the contralateral limb at 3 (operated limb: 34.6 ± 8.9°, contralateral limb: 23.7 ± 8.3°; P < 0.01) and 6 months (operated limb: 32.1 ± 9.7°, contralateral limb: 24.6 ± 8.2°; P = 0.03) postoperatively, but not at 12 months (operated limb: 27.1 ± 7.1°, contralateral limb: 23.1 ± 9.5°; P = 0.22) postoperatively. The knee extensor strength of the operated limb was significantly lower than that of the contralateral limb at 3 (operated limb: 1.00 ± 0.59 Nm/kg, contralateral limb: 1.37 ± 0.59 Nm/kg; P = 0.01), 6 (operated limb: 1.22 ± 0.55 Nm/kg, contralateral limb: 1.48 ± 0.60 Nm/kg; P < 0.01), and 12 months (operated limb: 1.39 ± 0.57 Nm/kg, contralateral limb: 1.55 ± 0.64 Nm/kg; P = 0.04) postoperatively. CONCLUSION: Knee extension deficits and extensor weakness persisted at 6 months after saucerization and repair of DLM tears. Postoperative rehabilitation should be focused on knee extension function.

Incidence of anterior cruciate ligament injury patterns in Japanese judo players from a nationwide insurance database.

Objective: This study aimed to characterize the age- and sex-specific Anterior cruciate ligament (ACL) injury rates and related injury patterns in judo players in Japan using the nationwide insurance database. Methods: This was a descriptive epidemiological study. We examined a total of 2142 adolescents with anterior cruciate ligament injuries registered in the insurance system of the Japan Sports Council between January 2009 and December 2018. The age- and sex-specific incidences were estimated for the levels of 7th, 8th, and 9th grades of junior high school and 10th, 11th, and 12th grades of high school. The anterior cruciate ligament injury circumstances were classified into three patterns based on the impact to the involved knee: high-impact valgus force, low-impact trunk displacement, or no-impact knee twisting. Results: The incidence of anterior cruciate ligament injury from the 7th to 12th grades were 0.5, 0.9, 0.9, 6.9, 8.6, and 6.1 per 1000 athlete-years in male players and 1.3, 3.8, 3.4, 16.8, 19.5, and 13.6 per 1000 athlete-years in female players. The most prevalent injury pattern was a low-impact contact injury (42.6%) with Osoto-gari, followed by a high-impact contact injury (29.8%). The concomitant medial collateral ligament (MCL) injury rate was 18.1%, which was correlated with a high-impact contact injury (p = 0.005) by multiple regression analysis. Conclusions: The highest incidence of age- and sex-specific anterior cruciate ligament injury was 19.5 per 1000 athlete-years in female high school students in the 11th grade. The most frequent injury pattern was low-impact contact injury with trunk displacement, indicating that trunk stabilization training could help prevent anterior cruciate ligament injury in judo.