活动平台膝关节单髁置换术后蹲起活动的运动生物力学

Biomechanical properties of knee after unicompartmental knee arthroplasty during squatting and standing up

目的对活动平台膝关节单髁置换术(UKA)后中远期患者膝关节的高载荷高屈曲度活动进行运动学特性和力矩分析,以评估UKA疗效、指导术后康复进程和预期并发症。方法本研究是临床队列研究。选取2016年6月至2018年6月收入西安交通大学第二附属医院行初次单侧内侧间室膝关节单髁置换手术患者,纳入经影像学诊断Kellgren&Lawrence分级1或2级,排除下肢创伤、肿瘤、身体质量指数(BMI)≥26及有并发症(假体松动、感染、对侧骨关节炎进展)等病例,术后定期(12、18、24个月)随访复查并筛选功能康复状态稳定患者26例入组。应用VICON T40三维运动分析系统和AMTI压力反馈系统测量UKA患者自然下蹲动作模式下的运动学和力矩参数。同时入组健康人群22例作为对照组,双尾t检验比较UKA术后与健康肢体的蹲起模式差异。结果术后平均随访时间为(24.4±1.5)个月。术后一年期UKA患肢膝关节最大内翻角度(21.20±2.30)°,最大胫骨内旋角度(16.90±1.80)°,伸膝力矩峰值(0.310±0.040)N/kg,内旋力矩峰值(0.020±0.008)N/kg,均较健侧肢体和健康人群有明显降低(t=2.6,P<0.05),而内翻力矩峰值(1.220±0.050)N/kg较健侧肢体和健康人群有明显升高(t=7.9,P<0.05)。结论活动平台UKA在改善患侧膝关节最大屈曲角度和伸膝力矩的同时对健侧肢体的生物力学指标无明显影响。术后早期患肢深度屈曲时伸肌力矩减少,内收肌力矩增加。随康复时间增加UKA患膝的活动度和伸肌力矩趋近于健康肢体,对中、长期理想的康复结果有积极的预测意义。

Objective To analyze knee kinematic and kinetic parameters after mobile bearing unicompartmental knee arthroplasty(UKA)during postoperative squatting-standing activity,so as to evaluate the efficacy of UKA,guide the process of postoperative rehabilitation and predict complications.MethodsThis study was a clinical cohort study.Thirty-one patients were admitted to the Second Affiliated Hospital of Xi’an Jiaotong University from June 2016 to June 2018 diagnosed with medial knee OA with primary UKA were followed up.After case screening,Kellgren&Lawrence stage one or two,lower limb trauma,tumor,excessive body mass index(BMI),and other complications were excluded,then 26 patients were recruited to take gait tests.Squatting-standing activities were performed under the test of Vicon T4010-Camera Motion Analysis System and Advanced Medical Technology Incorporated(AMTI)force plates preoperatively at different stages after UKA(12,18,24 months).Twenty-two healthy subjects were enrolled as the control group,and the difference of squatting pattern between the healthy group and the UKA patients was compared by double-tail t test.Results The average duration of follow-up was(24.4±1.5)months.At one year follow-up,the peak values of varus angle(21.20±2.30)°,internal rotation angle(16.90±1.80)°,the torques of knee extension(0.310±0.040)N/kg and internal rotation(0.020±0.008)N/kg of the UKA knees were inferior to contralateral knees.The peak adductor moment(1.220±0.050)N/kg was superior to the contralateral knees.Conclusions Mobile UKA can improve the ROM and torques of the involved knee and don’t affect the biomechanical indicators of healthy limbs.OA knees show decreased torque of knee extension and increased torque of knee adduction during active deep flexion activity in early postoperative period.With rehabilitation time elongation,the patients can achieve better range of motion and more natural torques of knee extension and adduction,which may predict ideal functional outcome in medium and long terms.