Grelsamer R P, Weinstein C H
Maimonides Medical Center and Hospital for Joint Diseases, New York, NY 11219, USA.
Clin Orthop Relat Res. 2001 Aug(389):9-14. doi: 10.1097/00003086-200108000-00003.
Although numerous prominent orthopaedists of the twentieth century considered the patella to be useless, even detrimental, it now is clear that the patella serves an important biomechanical function. It is a complex lever that magnifies the moment arm of the extensor mechanism. The patellofemoral contact area (the fulcrum of the lever) shifts along a proximodistal axis through the knee's arc of motion. As the knee flexes, the force within the patellar tendon diminishes relative to that of the quadriceps tendon. One's interpretation of patellar tracking is dependent on the choice of coordinates. When assessing tracking by way of anatomic coordinates, patellas are seen to be slightly lateralized at 0 degrees flexion and to follow similar paths down the trochlea. The tracking pattern is the result of an elaborate interplay between the quadriceps muscles, patellofemoral ligaments, the geometry of the trochlea, and the quadriceps angle. The articular cartilage of the patella is the thickest in the human body and does not follow the contour of the subchondral bone. Patellar cartilage is softer and more permeable than that of the trochlea. It is insensate. In size, nature, and number, the facets of the patellar articulation vary from person to person.
尽管20世纪众多杰出的骨科医生认为髌骨无用，甚至有害，但现在很明显，髌骨具有重要的生物力学功能。它是一个复杂的杠杆，可放大伸肌机制的力臂。髌股接触区域（杠杆的支点）在膝关节运动弧中沿近远轴移动。当膝关节屈曲时，髌腱内的力相对于股四头肌腱的力会减小。对髌骨轨迹的解读取决于坐标的选择。通过解剖坐标评估轨迹时，可观察到髌骨在0度屈曲时略向外侧偏移，并沿滑车向下遵循相似路径。这种轨迹模式是股四头肌、髌股韧带、滑车几何形状和股四头肌角之间复杂相互作用的结果。髌骨的关节软骨是人体中最厚的，且不遵循软骨下骨的轮廓。髌软骨比滑车软骨更软且渗透性更强。它没有感觉。髌骨关节面的大小、性质和数量因人而异。
