Kaiser Peter, Schmoelz Werner, Schoettle Philip, Zwierzina Marit, Heinrichs Christian, Attal Rene
Department of Trauma Surgery, Medical University of Innsbruck, Innsbruck, Austria.
Department of Orthopaedic and Trauma Surgery, Isar Medical Center, Munich, Germany.
Clin Biomech (Bristol). 2017 Aug;47:103-109. doi: 10.1016/j.clinbiomech.2017.06.007. Epub 2017 Jun 10.
Increased internal femoral torsion is regarded as a risk factor for patellar instability. Biomechanical investigations confirming this hypothesis are missing.
Eight fresh-frozen cadaver knees were tested on a specially designed simulator. Patellar motion and patellofemoral pressure were evaluated for 0°, 10°, and 20° of increased internal and external femoral torsion with native and with transected medial patellofemoral ligaments used to simulate patellar instability. A regression analysis was used for statistical analysis.
In native medial patellofemoral ligaments, there were no significant changes in mean or peak pressures for any torsional states (P≥0.07). At 20° increased internal femoral torsion, there was a significant center of force shift towards the lateral side (P=0.01). Patellar shift was directed laterally at low knee flexion angles up to 30°. Lateral patellar tilt increased significantly at 10° and 20° of increased internal femoral torsion (P≤0.004). In transected medial patellofemoral ligaments, mean pressure (P≤0.005) and peak pressure (P≤0.02) decreased significantly for all torsional states. There was a significantly greater lateral center of force shift with increased internal femoral torsion (P≤0.04). Lateral patellar tilt increased significantly (P<0.001). Patellar shift did not change significantly with increased internal femoral torsion (P≥0.30).
In a native medial patellofemoral ligament, 20° of increased internal femoral torsion can be regarded as a significant risk factor for patellar instability. With an insufficient medial patellofemoral ligament, 10° of increased internal femoral torsion already represents a significant risk factor.
股骨内旋增加被视为髌股关节不稳定的一个危险因素。目前尚缺乏证实这一假说的生物力学研究。
在一个专门设计的模拟器上对8个新鲜冷冻尸体膝关节进行测试。分别在股骨内旋和外旋增加0°、10°和20°的情况下，对完整的和切断内侧髌股韧带以模拟髌股关节不稳定的膝关节，评估髌骨运动和髌股压力。采用回归分析进行统计分析。
在完整的内侧髌股韧带中，任何扭转状态下的平均压力或峰值压力均无显著变化（P≥0.07）。在股骨内旋增加20°时，力的中心显著向外侧偏移（P = 0.01）。在屈膝角度达30°之前的低角度时，髌骨向外侧移位。在股骨内旋增加10°和20°时，髌骨外侧倾斜显著增加（P≤0.004）。在切断内侧髌股韧带的膝关节中，所有扭转状态下的平均压力（P≤0.005）和峰值压力（P≤0.02）均显著降低。随着股骨内旋增加，力的中心向外侧的偏移显著增大（P≤0.04）。髌骨外侧倾斜显著增加（P < 0.001）。随着股骨内旋增加，髌骨移位无显著变化（P≥0.30）。
在完整的内侧髌股韧带情况下，股骨内旋增加20°可被视为髌股关节不稳定的一个显著危险因素。在内侧髌股韧带功能不全时，股骨内旋增加10°就已构成显著的危险因素。
