University of Shanghai for Science and Technology
目的 根据全膝关节置换术后康复训练中的按压需求，针对曲面肢体设计一种基于3D打印支具的精准加压装置，并通过有限元分析验证该装置的有效性和安全性。方法 以下肢小腿腓肠肌部为加压对象，设计出由气压发生模块、充气气囊和3D打印支具所构成的曲面肢体精准加压装置，通过闭环控制算法在气囊内实现不同气压值，然后采集在各个实验条件下的“气囊-皮肤”接触面的压力分布数据，再应用仿真软件将压力分布数据作用于CT图像重建出的下肢生物力学三维模型，最后得到各个实验条件下的有效按压面积分数和关节微动角度，从而判断系统的有效性和安全性。结果 采用优选的4cm偏移量和四压条气囊形态的方案，在40、50、60、70、80mmHg (1 mmHg=0.133 kPa)的不同囊内压强值下，分别仿真得到膝关节综合微动角度为5.3°、6.1°、7.2°、9.5°、10.6°，有效按压面积分数可达90.8%～95.2%。结论 在优选方案下，不同囊内压强设置值所导致的关节微动角度和有效按压面积分数综合最优，满足有效性和安全性的设计目标。研究结果有助于分析加压系统对肢体的生物力学影响，对全膝关节置换术后安全有效地进行康复训练具有重要的意义。
Objective A 3D printing precise pressure device was designed specifically targeted at cambered limbs according to the requirement of postoperative rehabilitation of total knee replacement, and its effectiveness and safety was verified by finite element analysis. Method Based on lower limbs gastrocnemius muscle as the pressurized objects, the precise pressure device was designed which contained an air pressure generating module, an inflatable airbag and a 3D printing brace. Through the closed loop control algorithm, the device stably supplied different pressure values in the airbag. Distributed pressure data of the "Airbag-Skin" within contact surface was collected under different experimental conditions and imported into biomechanical simulation software which combined CT images to reconstruct three-dimensional model of the leg mechanics. Finally, effective compression area fraction and the joint micro-motion angle under each condition was obtained, thereby verified the effectiveness and safety of the system. Result Using general preferred 4cm size offset and four-barrel airbag configurations, the knee joint micro-motion angles were 5.3°, 6.1°, 7.2°, 9.5°, 10.6°，which simulated at different airbag pressure values of 40, 50, 60, 70, 80mmHg (1 mmHg=0.133 kPa), respectively. The effective compression area fraction can be up to 90.8%～95.2%. Conclusion On the condition of the preferred embodiment, the dynamic range of joint micro-motion angle and the effective compression area fraction caused by different airbag pressure values were the best and met the design requirements of effectiveness and safety. The results can contribute to analyzing the compression system’s influence on limbs biomechanics. Besides, it is of great significance for rehabilitation training effectively and safely after total knee replacement.