全膝关节置换前后患者下肢肌骨模型步态模拟与分析

Gait Simulation and Analysis of Lower Limb Musculoskeletal Model before and after Total Knee Arthroplasty

目的比较分析全膝关节置换患者术前、术后步态周期站立相下肢肌肉激活规律和膝关节受力。方法基于Open Sim平台建立1名健康受试者和3名单侧全膝关节置换(total knee arthroplasty,TKA)患者术前、术后下肢肌骨模型。使用三维动作捕捉系统和测力台采集受试者步行期间下肢运动学数据和地面反作用力作为输入参数,模拟计算下肢肌肉激活和膝关节受力。结果肌骨模型计算结果与基于三维动作捕捉系统的逆动力学计算结果基本一致。不同于健康受试者,患者股直肌在承重反应期、支撑相中期激活,3名患者术后股四头肌的激活时间与激活程度较术前明显不同。患者TKA术前关节受力峰值为3. 15、2. 95、3. 43倍身体质量(body weight,BW),支撑相中期维持2倍BW以上载荷。TKA术后关节受力峰值分别2. 09、2. 48和3. 73倍BW。结论所建肌骨模型计算结果具有一定的可靠性,该模型今后可为TKA治疗提供生物力学的辅助手段。

Objective To compare and analyze the lower limb muscle activity and knee joint force during the stance periods of gait cycle in patients with osteoarthritis before and after total knee arthroplasty(TKA).Methods Based on the OpenSim platform,lower extremity musculoskeletal models of one healthy subject and three patients with osteoarthritis before and after TKA were established.A three-dimensional(3D)motion capture system and a force platform were used to collect the lower limb kinematic data and the ground reaction force during walking,which were used as input parameters to simulate the lower limb muscle activation and knee joint forces.Results The results from the musculoskeletal model were consistent with the results by inverse dynamics based on the 3D motion capture system.The patient’s rectus femoris was activated in the loading response and mid stance phases,which was different from that of healthy subject.The activation timing and amplitude of the quadriceps muscle in 3 patients were significantly different before and after TKA.The peak joint forces of 3 patients before TKA were 2.95,3.15 and 3.43 times of body weight(BW)with the constant load of more than2 times of BW during stand phase.The peak joint force after TKA were 2.09,2.48 and 3.96 times of BW respectively.The joint force was not improved and the knee function did not reach the normal level six months after TKA.Conclusions The results of the established musculoskeletal model have certain reliability,and this model can provide a biomechanical auxiliary method for TKA surgery in the future.