平足症是足踝外科的常见病，随着病情发展，会导致严重的疼痛和行走不稳定，甚至丧失劳动能力。目前治疗方法众多，但缺乏机制认识和统一观点。而且传统治疗方法创伤大，大多会使足部处于非生理状态，各种并发症发生率高。近年来，根据后足解剖特点、国外少量报道和我们的临床工作发现，距下关节的对合与稳定在平足症的形成与治疗中起到至关重要的作用。目前有趋势，成人和儿童平足症的治疗都聚焦在距下关节。本课题旨在通过解剖学和影像学研究测量相关结构；采用252排CT动态观察比较正常和平足症病理状态下后足运动特点和规律；在构建的平足症标本模型上通过生物力学和有限元实验，研究平足症足部的生物力学特点和不同手术方法对后足的影响，从而明确距下关节在平足症中的作用和意义。在以上研究基础上比较研究不同手术方法的临床疗效。以探讨科学合理的治疗策略和手术方法，对临床合理治疗平足症提供理论依据，以提高临床近期和远期疗效，节约医疗资源。

Flatfoot is a common foot deformity. With the progression of the disease, flatfoot will cause severe pain, instability, and even the loss of the ability to work. Its pathogenesis is not clear and the treatment is still controversial. Most of the traditional treatment methods will make the foot in a non-physiological state, and various complications such as malunion, nonunion, incision near joints arthritis are common. In recent years, according to some foreign reports and our clinical work, we found that the integration and stability of the subtalar joint play a crucial role in the formation and treatment of flatfoot. Currently there is a trend that the treatment of both adults and children flatfoot is focused on the subtalar joint. The aims of this project contains measurement of related bone - ligament structure parameter with use of anatomical and radiological methods; and comparison dynamic motion characteristics between normal and flatfoot with 252 slice CT; to built flatfoot model and evaluate different types of treatments on the effects of hindfoot with use of biomechanical and finite element analysis methods. Thus to clear the role and significance of subtalar joint in the flatfoot. And in order to improve the efficacy and long - term outcomes and save medical resources and costs basic of current results.