Senavongse W, Farahmand F, Jones J, Andersen H, Bull A M J, Amis A A
Biomechanics Section, Mechanical Engineering Department, Imperial College, Exhibition Road, London, SW7 2AZ, UK.
J Orthop Res. 2003 Sep;21(5):780-6. doi: 10.1016/S0736-0266(03)00061-5.
Patellofemoral joint instability is a common clinical problem. However, little quantitative data are available describing the stability characteristics of this joint. We measured the stability of the patella against both lateral and medial displacements across a range of knee flexion angles while the quadriceps were loaded physiologically. For eight fresh-frozen knee specimens a materials testing machine was used to displace the patella 10 mm laterally and 10 mm medially while measuring the required force, with 175 N quadriceps tension. The patella was connected via a ball-bearing patellar mounting 10 mm deep to the anterior surface to allow natural tilt and other rotations. Patellar force-displacement behavior was tested at flexion angles of 0 degrees, 10 degrees, 20 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees. Significant differences were found between the lateral and medial restraining forces at 10 mm displacement. For lateral displacement, the restraining force was least at 20 degrees of knee flexion (74 N at 10 mm displacement), rising to 125 N at 0 degrees and 90 degrees of knee flexion. The restraining force increased progressively with knee flexion for medial patellar displacement, from 147 N at 0 degrees to 238 N at 90 degrees. With quadriceps tension, the patella was more resistant to medial than lateral displacement. Our finding that lateral patellar displacement occurred at the lowest restraining force when the knee was flexed 20 degrees agrees with clinical experience of patellar instability.
髌股关节不稳是一种常见的临床问题。然而，关于该关节稳定性特征的定量数据却很少。我们在股四头肌承受生理负荷的情况下，测量了髌骨在一系列膝关节屈曲角度下抵抗外侧和内侧移位的稳定性。对于8个新鲜冷冻的膝关节标本，使用材料试验机将髌骨分别向外侧和内侧移位10毫米，同时测量所需的力，股四头肌张力为175牛。髌骨通过一个深10毫米的滚珠轴承髌骨固定装置与前表面相连，以允许自然倾斜和其他旋转。在0度、10度、20度、30度、45度、60度和90度的屈曲角度下测试髌骨的力-位移行为。发现在10毫米位移时，外侧和内侧的约束力量存在显著差异。对于外侧移位，在膝关节屈曲20度时约束力量最小（10毫米位移时为74牛），在膝关节屈曲0度和90度时升至125牛。对于髌骨内侧移位，约束力量随着膝关节屈曲而逐渐增加，从0度时的147牛增加到90度时的238牛。在股四头肌张力作用下，髌骨对内侧移位的抵抗比对外侧移位的抵抗更强。我们的研究发现，当膝关节屈曲20度时，髌骨外侧移位发生时的约束力量最低，这与髌股关节不稳的临床经验相符。
