Rupp Marco-Christopher, Hochberger Felix, Berthold Daniel P, Muench Lukas N, Imhoff Andreas B, Siebenlist Sebastian, Willinger Lukas
Department of Sports Orthopaedics, Technical University Munich, Munich, Germany.
Department of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, Ludwig Maximilian University of Munich (LMU Munich), Munich, Germany.
Orthop J Sports Med. 2024 Mar 6;12(3):23259671241232397. doi: 10.1177/23259671241232397. eCollection 2024 Mar.
Lower limb malalignment has been associated with osteochondritis dissecans (OCD). However, the location of the OCD lesion often is not concordant with the mechanical leg axis. Other potentially modifiable alignment parameters may influence the propensity for impingement of the femoral condyles.
To assess differences in lower limb alignment (LLA) and relative tibiofemoral position between patients with medial (MFC-OCD) or lateral OCD (LFC-OCD) of the femoral condyle.
Cohort study; Level of evidence, 3.
Patients ≤30 years old who were diagnosed with unicondylar OCD between January 2010 and January 2020 were eligible for this study. Included were 55 patients (age, 20.8 ± 4.5 years)-46 with MFC-OCD and 9 with LFC-OCD. Preoperative standing long-leg radiographs were studied to obtain primary outcomes-including LLA and mechanical alignment analyses-and secondary outcomes-including knee joint obliquity angle; rotation angle; medial, central (c-subluxation), and lateral subluxation (L-subluxation) of the tibia relative to the femur in the coronal plane; and tibiofemoral joint line center distance (TFJCD).
With regard to primary outcomes, LLA was significantly different between MFC-OCD (1.7°± 3.1° varus) and LFC-OCD (2.7 ± 3.1° valgus) ( < .001), and 78% (36/46) of patients with MFC-OCD had varus alignment, whereas 78% (7/9) of patients with LFC-OCD had valgus alignment ( < 0.002). With regard to secondary outcomes, patients with MFC-OCD had a more medial tibial position in relation to the femur, with a significantly smaller rotation angle (5.6°± 2.4° vs 9.6°± 3.6°; < .001), a smaller C-subluxation (7.2 ± 6.6 vs 14.9 ± 8.8 mm; < .01), a smaller L-subluxation (2.3 ± 2.6 vs 4.4 ± 2.7 mm; < .05), and reduced TFJCD (3.5 ± 1.7 vs 6.6 ± 1.8 mm; < .001) compared with the LFC-OCD group. For patients with MFC-OCD, the size of the OCD was significantly correlated with C-subluxation ( = 0.412; = .006).
LLA was significantly different according to OCD location. In patients with MFC-OCD, the tibia was subluxated medially, resulting in a change of joint geometry by approximation of the medial tibial eminence toward the medial femoral condyle, potentially causing excessive pressure overload and microtrauma of the cartilage. Interestingly, the extent of subluxation was correlated with OCD size.
下肢力线不正与剥脱性骨软骨炎（OCD）有关。然而，OCD病变的位置往往与下肢机械轴不一致。其他可能可改变的力线参数可能会影响股骨髁撞击的倾向。
评估股骨内侧髁骨软骨炎（MFC - OCD）或外侧髁骨软骨炎（LFC - OCD）患者下肢力线（LLA）和相对胫股位置的差异。
队列研究；证据等级，3级。
2010年1月至2020年1月期间诊断为单髁OCD且年龄≤30岁的患者符合本研究条件。纳入55例患者（年龄20.8±4.5岁），其中46例为MFC - OCD患者，9例为LFC - OCD患者。研究术前站立位长腿X线片以获得主要结局（包括LLA和机械力线分析）和次要结局（包括膝关节倾斜角、旋转角、胫骨在冠状面相对于股骨的内侧、中央（c - 半脱位）和外侧半脱位（L - 半脱位）以及胫股关节线中心距离（TFJCD））。
关于主要结局，MFC - OCD（内翻1.7°±3.1°）和LFC - OCD（外翻2.7±3.1°）之间的LLA有显著差异（P <.001），46例MFC - OCD患者中有78%（36/46）为内翻力线，而9例LFC - OCD患者中有78%（7/9）为外翻力线（P < 0.002）。关于次要结局，MFC - OCD患者的胫骨相对于股骨的位置更偏内侧，旋转角显著更小（5.6°±2.4°对9.6°±3.6°；P <.001），C - 半脱位更小（7.2±6.6对14.9±8.8mm；P <.01），L - 半脱位更小（2.3±2.6对4.4±2.7mm；P <.05），与LFC - OCD组相比TFJCD减小（3.5±1.7对6.6±1.8mm；P <.001）。对于MFC - OCD患者，OCD的大小与C - 半脱位显著相关（r = 0.412；P =.006）。
根据OCD的位置，LLA有显著差异。在MFC - OCD患者中，胫骨向内侧半脱位，导致内侧胫骨嵴向内侧股骨髁靠近，从而改变关节几何形状，可能导致软骨过度压力过载和微创伤。有趣的是，半脱位程度与OCD大小相关。
