The anterior cruciate ligament (ACL) is one of the most frequently studied structures of the musculoskeletal system and continues to stimulate debate and challenges among researchers and surgeons. The ultimate goal of anatomic reconstruction surgery is to restore the native anatomy as much as possible. However, this requires thorough knowledge of its anatomy. The aim of this article is to review the current knowledge of the anatomy of ACL along with its macrostructural and ultrastructural properties.

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Union rates and nonunion characteristics of FO might differ according to its level, apposition of bone ends, and contact area. The fate of FO might also affect the union of HTO.

The flexion of the femoral component in the sagittal plane in unicompartmental knee arthroplasty (UKA) was analyzed radiographically in this study. Thirty medial and 30 lateral UKAs were included. The sagittal flexion angles were measured both relative to the posterior femoral cortex and midline sagittal distal femoral axis. Both of the measurement methods revealed that the femoral components were inserted in a significantly more flexed fashion in the medial UKA group. Neither preoperative nor postoperative tibial slope did have any significant effect on the sagittal flexion angle. To the best of our knowledge, this is the first study demonstrating an angular difference in the sagittal flexion of the femoral components between medial and lateral UKAs.

The findings of this study showed that MR arthrography was a reliable diagnostic tool in evaluating previously repaired menisci. Yet diagnosis of incomplete meniscal lesions seemed to be challenging.

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Level IV, retrospective case series.

BackgroundThe mid-substance central defect injury has been used to investigate the primary healing capacity of the anterior cruciate ligament (ACL) in a goat model. The sagittal plane stability on this model has not been confirmed, and possible effects of fat pad excision on healing have not been evaluated. We hypothesize that excising the fat pad tissue results in poorer ligament healing as assessed histologically and decreased tensile strength of the healing ligament. We further hypothesize that the creation of a central defect does not affect sagittal plane knee stability.MethodsA mid-substance central defect was created with a 4-mm arthroscopic punch in the ACLs of right knees of all the subjects through a medial mini-arthrotomy. Goats were assigned to groups based on whether the fat pad was preserved (group 1, n = 5) or excised completely (group 2, n = 5). The left knees served as controls in each goat. Histopathology of the defect area along with measurement of type I collagen in one goat from each group were performed at 10th week postoperatively. The remaining knees were evaluated biomechanically at the 12th week, by measuring anterior tibial translation (ATT) of the knee joints at 90° of flexion and testing tensile properties (ultimate tensile load (UTL), ultimate elongation (UE), stiffness (S), failure mode (FM)) of the femur-ACL-tibia complex.Results and discussionHistopathology analysis revealed that the central defect area was fully filled macroscopically and microscopically. However, myxoid degeneration and fibrosis were observed in group 2 and increased collagen type I content was noted in group 2. There were no significant differences within and between groups in terms of ATT values (p = 0.715 and p = 0.149, respectively). There were no significance between or within groups in terms of ultimate tensile load and ultimate elongation; however, group 2 demonstrated greater stiffness than group 1 that was correlated with the fibrotic changes detected microscopically (p = 0.043).ConclusionsThe central defect type injury model was confirmed to be biomechanically stable in a goat model. Resection of the fat pad was noted to negatively affect defect healing and increase ligament stiffness in the central defect injury model.