目的 研究一种新型3D打印下肢不等长补高鞋垫的拓扑结构及其对下肢生物力学的影响。方法 通过变密度法对鞋垫中后部进行拓扑结构优化,根据鞋垫受力区域分块进行力的加载和边界条件的设置,采用选择性激光烧结方式打印TPU补高鞋垫。将该鞋垫应用于9例下肢不等长患者中,运用VAS和Maryland足部功能评分表比较患者使用鞋垫前后的疼痛及足部功能变化,并通过三维步态分析双下肢步态时空参数和垂直地面反作用力。结果 患者穿戴3D打印补高鞋垫后,VAS评分降低,Maryland足部功能评分增加,双下肢垂直地面反作用力降低,步频、支撑相和摆动相的双下肢差距缩小。结论 拓扑优化后的3D打印鞋垫可提高双下肢运动节律的协调性,减缓地面冲击力,缓解疼痛和改善足部功能,可为临床上矫正双下肢不等长提供一种有效的个性化补高鞋垫矫正方案。
Objective To study the topological structure of a new type of 3D printed height incresing insole insole for leg length discrepancy and its effect on lower limbs biomechanics. Methods The topological structure of the middle and rear part of the insole was optimized by Solid Isotropic Microstructures with Penalization, the force was loaded and the boundary conditions were set according to the force area of the insole, and the height incresing insole with TPU(Thermoplastic polyurethanes) material was printed by Selected Laser Sintering. The insole was used in 9 patients with leg length discrepancy, VAS and Maryland foot function score were used to compare the pain and foot function changes of patients before and after using insole, at the same time, the three-dimensional gait analysis system was used to compare the spatiotemporal parameters and vertical ground reaction force of both lower limbs. Results After wearing the 3D printed insole, VAS score decreased, Maryland foot function score increased, vertical ground reaction force of both lower limbs decreased, and the difference of cadence, stance phase and swing phase between the two lower limbs decreased. Conclusions The 3D printed height incresing insole insole after topology optimization can improve the coordination of lower limb movement, reduce the ground reaction force, relieve pain and improve foot function. It can provide an effective personalized orthopedic plan for the treatment of leg length discrepancy in clinic.