身体承重对膝关节生物力学研究的影响

为了解自体承重对膝关节生物力学的影响，本研究以连续性Ｘ光数位化系统拍摄及分析十二位正常人的膝关节，将其分成有自体承重及无自体承重两组来探讨，分析比较的参数包含膝关节弯曲角度，股四头肌的力臂，髌骨肌腱受力与股四头肌力的比值及髌股骨关节受力与髌骨肌腱受力的比值。研究结果显示，自体承重的确对膝关节生物力学分析有所影响，所以本研究建议，膝关节生物力学的研究应考虑自体承重的因素。

THE INFLUENCE OF BODY WEIGHT-BEARING ON KNEE JOINT BIOMECHANICS

In order to understand the effects of body weight-bearing on knee joint biomechanics, a video-fluoroscopic digitizing system was applied and in vivo human knee joint motions of 12 healthy adults under body weight-bearing and no weight-bearing conditions were recorded, digitized and analyzed. The changes of following parameters, including the knee flexion angle versus time, the length of the moment arm of the quadriceps muscle, the ratio between patellar tendon force and quadriceps muscle force, the ratio between patellofemoral joint reaction force and patellar tendon force in the sagittal plane during knee flexion-extension exercises under weight-bearing and no weight-bearing conditions were measured and compared. The results revealed that biomechanics of the knee joint motion under weight-bearing and no weight-bearing conditions were quite differnet. The knee under body weight-bearing condition extended rapidly and decelerated at near6-extension but the knee without body weight-bearing extended and flexed at almost equal speeds. The moment arm of the quadriceps muscle was shorter in knee exercise with body weight-bearing than that with no body weight-bearing but two groups showed similar patterns of change. The ratio between the tension of the patellar tendon and the quadriceps muscle force changed less obviously in the group performing knee exercise under body weight-bearing than the group performing knee exercise without body weight-bearing. The ratio between the patellofemoral joint reaction force and the quadriceps muscle force changed more obviously in the group with body weight-bearing than the group without body weight-bearing. Therefore,we concluded that body weight-bearing has strong influence on knee joint biomechanics. Besides, we should be more judicious in conducting in vitro studies of knee biomechanics because body weight-bearing is definitely a determining factor.