Department of Surgery, Central Finland Hospital, Keskussairaalantie 19, 40620, Jyväskylä, Finland.
Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.
Knee Surg Sports Traumatol Arthrosc. 2021 Dec;29(12):4241-4250. doi: 10.1007/s00167-021-06547-2. Epub 2021 Mar 28.
Despite the comprehensive literature on the anatomical risk factors for patellar dislocation, knowledge on the risk factors for subsequent osteochondral fracture (OCF) remains limited.
Magnetic resonance imaging was used to compare measures of patellofemoral anatomy in patients with OCF after patellar dislocation and propensity score matched patients without OCF. For differing measures, limit values showing a 50% probability for the occurrence of OCF were calculated using predictive logistic regression modelling. Proportions of abnormal measures in the groups were compared using Chi-square test. The association of anatomical measures with OCF location was examined by comparing subgroup mean values in the different OCF locations.
Propensity score matching provided a total of 111 matched pairs of patients with OCF and patients without OCF. The patients with and without OCF differed in patellotrochlear index (PTI; 0.54 [95% CI 0.52-0.57] vs. 0.47 [95% CI 0.45-0.49]; p < 0.001), tibial tubercle-posterior cruciate ligament distance (TT-PCL; 21.6 mm [95% CI 21.0-22.3 mm] vs. 20.5 mm [95% CI 20.0-21.1 mm]; p = 0.013), trochlear depth (2.5 mm [95% CI 2.3-2.7 mm] vs. 3.0 mm [95% CI 2.8-3.2 mm]; p < 0.001) trochlear facet asymmetry ratio (0.54 [95% CI 0.51-0.57] vs. 0.43 [95% CI 0.42-0.45]; p < 0.001) and trochlear condyle asymmetry ratio (1.04 [95% CI 1.03-1.04] vs. 1.05 [95% CI 1.04-1.05]; 0.013. Thresholds for increased OCF risk were > 0.51 for PTI > 21.1 mm for TT-PCL < 2.8 mm for trochlear depth > 0.48 for trochlear facet asymmetry ratio and < 1.04 for trochlear condyle asymmetry ratio.
In patients with OCF after patellar dislocation, trochlear configuration and patella vertical location were closer to normal anatomy, whereas patella lateralization was more severe when compared to patients without OCF. These anatomical factors contribute to the risk of OCF during patellar dislocation.
III.
尽管有大量关于髌脱位解剖风险因素的文献，但对骨软骨骨折（OCF）后续风险因素的了解仍然有限。
使用磁共振成像（MRI）比较 OCF 后髌脱位患者和倾向评分匹配无 OCF 患者的髌股解剖结构。对于不同的测量指标，使用预测逻辑回归模型计算出发生 OCF 概率为 50%的限值。使用卡方检验比较两组中异常测量指标的比例。通过比较不同 OCF 部位的亚组平均数值，检查解剖学指标与 OCF 部位的关系。
倾向评分匹配共提供了 111 对 OCF 患者和无 OCF 患者的匹配对。有和无 OCF 的患者在髌股指数（PTI；0.54 [95%置信区间 0.52-0.57] vs. 0.47 [95%置信区间 0.45-0.49]；p < 0.001）、胫骨结节-后十字韧带距离（TT-PCL；21.6 毫米 [95%置信区间 21.0-22.3 毫米] vs. 20.5 毫米 [95%置信区间 20.0-21.1 毫米]；p = 0.013）、滑车深度（2.5 毫米 [95%置信区间 2.3-2.7 毫米] vs. 3.0 毫米 [95%置信区间 2.8-3.2 毫米]；p < 0.001）、滑车面不对称比（0.54 [95%置信区间 0.51-0.57] vs. 0.43 [95%置信区间 0.42-0.45]；p < 0.001）和滑车髁不对称比（1.04 [95%置信区间 1.03-1.04] vs. 1.05 [95%置信区间 1.04-1.05]；0.013）方面存在差异。PTI > 0.51、TT-PCL < 21.1 毫米、滑车深度 < 2.8 毫米、滑车面不对称比 > 0.48、滑车髁不对称比 < 1.04时，发生 OCF 的风险增加。
在髌脱位后发生 OCF 的患者中，滑车形态和髌骨垂直位置更接近正常解剖结构，而与无 OCF 患者相比，髌骨外侧化更为严重。这些解剖因素导致了髌脱位时发生 OCF 的风险。
III 级。
