正常与畸形愈合跟骨应力分布的比较研究  

Comparison of stress distribution between normal and malunion calcaneus

作　　者：黄海晶[1] 马信龙[1] 马剑雄[2] 金鸿宾[1] 

机构地区：[1]天津医院骨科,300211 [2]天津医科大学生物医学工程系

出　　处：《中华骨科杂志》2013年第4期336-341,共6页Chinese Journal of Orthopaedics

摘　　要：目的探讨在静力载荷作用下，正常与畸形愈合跟骨的应力分布差异。方法将正常跟骨有限元模型的后关节面由内向外、由前向后楔形切除，模拟骨折后距下关节面塌陷的畸形愈合模型。切除前Boehler角为35°，切除后为0°自足跟及跟腱附着点处分别垂直向上对模型施加320N和160N的载荷，观察畸形愈合跟骨的Vonmises应力分布，并与正常模型进行比较。结果畸形愈合跟骨的距下关节面应力降低，应力分布特点为从正常的跟骨前中关节面为主要应力区转为跟骨外侧紧靠跟骰关节处，外侧主要应力区要高于内侧，是支撑载荷的主要部位。从跟骨结构的细化比较来看，首先，距下关节面顶部的塌陷造成跟骨主要应力区部分后移，转至跟腱附着点处由正常的（1．51±0．22）MPa增至（3．11±0．24）MPa，而距下关节面顶部的应力由正常的（6．71±0．37）MPa减至（2．83±0．49）MPa。其次，跟骨前侧近跟骰关节处应力明显加大，由正常的（0．46±0．15）MPa增至（2．13±0．15）MPa，载距突应力由5．18MPa减少至1．41MPa。结论跟骨骨折距下关节面塌陷是多数病理变化的主因，在临床治疗中应先解决距下关节面的塌陷问题，恢复跟骨正常高度，跟骨内部应力的分布对解决跟骨骨折后期出现的相关部位疼痛至关重要。Objective To compare the stress distribution of calcaneal compression articular surface and normal surface in biomechanical analysis. Methods The posterior articular facet of the normal finite element model was wedged resected from inside to outside and from front to back, to imitate the malunion model with subtalar articular surface collapse after fracture. The Boehler angle was 35° before wedged, and 0° after wedged. On heel and Achilles tendon attachment point, 320 N and 160 N loads were applied vertically upwards respectively. Compare calcaneal Vonmises stress distribution between malunion and normal model. Results Judging from the general stress distribution of malunion of calcaneal, subtalar joint stress reduced. The main stress area of normal bone joints was in articular surface, while the main stress area of malunion model was in the lateral calcaneal close to the calcaneocuboid joint. The main stress of the outboard is high- er than that of inboard. Outboard is the main part of supporting load. Judging from the detailed comparison with bone structure, first of all, the subsidence of subtalar joint top resulted in partial backward of the main stress of the calcaneus, which shifted to the Achilles tendon attachment point. It increased from normal （1.51±0.22） MPa to （3.11±0.24） MPa. Joint top of the stress reduced from normal （6.71±0.37） MPa to （2.83±0.49） MPa. Secondly, the calcaneus stress of the former calcaneoeuboid articulation significantly increased, which increased from normal （0.46±0.15） MPa to （2.13±0.15） MPa, and sustentaeulum tali stress decreased from 5.18 MPa to 1.41 MPa. Conclusion By finite element model of this subject, the study proves that sub- talar joint surface collapsed in caleaneal fractures is the main causes of most pathological changes. The problem of the joint surface subsidence should be resolved firstly in a clinical treatment, and the normal height of the calcaneus should be restored. The internal stress distribution of ealeaneal is essential to

关 键 词：有限元分析 跟骨 骨折愈合 应力 物理 

分 类 号：R687.3[医药卫生—骨科学]