Background:Osteochondritis dissecans (OCD) is a condition characterized by abnormal subchondral bone with disturbance of overlying articular cartilage. The role of weightbearing alignment in the pathophysiology of OCD lesion development is not fully understood.Hypothesis:Lower extremity mechanical axis would be concordant with femoral condylar OCD lesion location.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Cases were identified from a single, large academic institutional database using International Classification of Diseases, Ninth Revision and Tenth Revision and Current Procedural Terminology codes associated with OCD. Patients were included if they had a magnetic resonance imaging scan demonstrating the OCD lesion and lower extremity alignment radiographs. OCD lesion location was identified using Cahill and Berg zones. The primary outcome was the association of OCD lesion location with weightbearing mechanical axis. Secondary outcomes included the association of mechanical axis with skeletal maturity, OCD lesion stability, and treatment. For unilateral OCD lesions, mechanical axis was compared between affected and unaffected lower extremities.Results:A total of 86 patients (95 knees) with an OCD lesion of the femoral condyle were identified. The population was 74% male, and the mean age was 21 years. In total, 65% of knees had closed physes, 82% of lesions were unstable, and 85% underwent a surgical procedure. Mechanical axis was located in the same zone as the OCD lesion in 48% of cases and within the same compartment in 56% of cases. Spearman correlation coefficient demonstrated a moderate positive correlation (rs = 0.59). No significant differences were found in the association of mechanical axis and OCD lesion location in subgroup analysis of medial versus lateral femoral condylar OCD lesions, skeletal maturity, stability of the lesion, or treatment group. For patients with varus alignment and medial femoral condylar OCD lesions, the mean lateral distal femoral angle was 89.9°, and medial proximal tibial angle was 85.4°; for valgus alignment and lateral femoral condylar lesions, the lateral distal femoral angle was 84.8°, and medial proximal tibial angle was 88.8°. Patients with unilateral medial femoral condylar OCD lesions were more likely to have varus alignment of the affected extremity compared with the contralateral extremity (59% vs 36%; P = .01).Conclusion:This study demonstrated a relationship between lower extremity mechanical weightbearing axis and femoral condylar OCD location. Patients with unilateral medial femoral condylar OCD lesions frequently had asymmetric varus alignment in the affected extremity.

中文翻译：

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机械轴与股骨髁剥脱性骨软骨炎的关联


背景：剥脱性骨软骨炎（OCD）是一种以软骨下骨异常伴上覆关节软骨紊乱为特征的疾病。负重排列在强迫症病变发展的病理生理学中的作用尚不完全清楚。假设：下肢机械轴将与股骨髁强迫症病变位置一致。研究设计：横断面研究；证据水平，3.方法：使用国际疾病分类第九版和第十版以及与强迫症相关的现行程序术语代码从单个大型学术机构数据库中识别病例。如果患者的磁共振成像扫描显示强迫症病变和下肢对齐X光片，则患者被纳入。使用 Cahill 和 Berg 区确定 OCD 病变位置。主要结果是强迫症病变位置与负重机械轴的关联。次要结果包括机械轴与骨骼成熟度、强迫症病变稳定性和治疗的关系。对于单侧 OCD 病变，比较受影响和未受影响的下肢之间的机械轴。结果：总共确定了 86 名患有股骨髁 OCD 病变的患者（95 个膝盖）。人口中 74% 为男性，平均年龄为 21 岁。总共，65% 的膝关节已闭合，82% 的病变不稳定，85% 的膝关节接受了外科手术。 48% 的病例机械轴与强迫症病变位于同一区域，56% 的病例机械轴位于同一隔室内。 Spearman 相关系数表现出中度正相关（r s = 0.59）。 在股骨内侧髁强迫症病变、骨骼成熟度、病变稳定性或治疗组的亚组分析中，机械轴与强迫症病变位置的关联没有发现显着差异。对于内翻排列和股骨内侧髁 OCD 病变的患者，平均股骨远端外侧角为 89.9°，胫骨近端内侧角为 85.4°；对于外翻排列和股骨外侧髁病变，股骨远端外侧角为84.8°，胫骨近端内侧角为88.8°。与对侧肢体相比，单侧股骨内侧髁 OCD 病变患者更容易出现患肢内翻排列（59% vs 36%；P = .01）。结论：本研究证明了下肢机械负重轴之间的关系和股骨髁强迫症位置。单侧股骨内侧髁强迫症病变患者的受影响肢体经常出现不对称的内翻排列。