【专题文献】之人工髋关节置换——下肢假体周(11)

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

Tibial periprosthetic fractures are far less common. If the component is stable, the fracture can be treated using a buttress plate; peri-articular plates have also been advocated for complex metaphyseal fractures in the presence of a stable component. These plates are anatomically pre-contoured, so require minimal intra-operative bending. The use of locking screws may give a more stable fixation.

If the prosthesis is loose and there is radiological evidence of osteolysis is a difficult problem. Removal of the prosthesis and cement and poor bone stock, can result in significant bony deficiency. This can be made up relatively easily by using a combination of thicker polyethylene implants and metal augments. Small defects can also be filled using cement (poly-methylmethacrylate) but as this has no biological properties, it may prevent fracture healing. In cases of severe bone loss, a custom made mega-prosthesis may have to be considered as this allows reconstruction of fractures with significant bone defects. The disadvantages however are the cost and the lack of intra-operative flexibility.

胫骨的假体周围骨折不常见。如果假体是稳定的，骨折可以使用一块碟形钢板治疗。在假体稳定时，关节周围钢板也被推荐用于复杂的干骺端骨折。这些钢板是术前解剖型塑形的，这样术中可以最小的弯曲。使用锁定螺钉可能得到更稳定的内固定。

如果假体松动，有放射学表现的骨溶解，这将是一个困难的问题。取出假体和骨水泥，和较差的骨量，能导致显著的骨缺损。这可以相对容易的通过联合使用加厚的聚乙烯假体和金属加强而解决。小的缺损可以使用骨水泥填充，但是骨水泥没有生物学属性，因此它可能影响骨折愈合。在严重骨丢失的病例，可能必须考虑定制的大型假体，该假体可以在显著骨缺损的情况下完成骨折重建。然而，该方法的缺点是费用较高，且缺乏术中灵活性。

In all cases where there is loss of bone with comminution and poor bone stock, bone grafting is extremely helpful. Autologous graft is best due to its osteoconductive and osteoinductive properties, but in the majority of patients sufficient volume is not available, limiting its usefulness. Another option is the use of a structural allograft/implant composite; Engh et al. reported good results using structural allograft in cases of severe tibial bone loss.27

Problems have also been reported with periprosthetic fractures after unicompartmental knee replacement, presenting with significant loosening of the components and tibial bone loss. They should be managed by conversion to a total knee replacement with allograft to cover the tibial bone defect which has been shown to have good results.28

所需足够数目的骨块是得不到的，因此限制了它的使用。另一个选择是使用结构性同种异体骨/内植物复合物。Engh等报道对于严重胫骨骨丢失的病例，使用结构性同种异体骨移植，有好的效果。

膝关节单髁置换术后假体周围骨折的问题也有报道，表现出显著的假体松动和胫骨骨丢失。通过转换到全膝置换术，并使用同种异体骨移植以覆盖胫骨缺损，通过这种方式处理，己经显示出有较好结果。 在所有的病例中，当骨丢失伴有较差的骨量，骨移植格化有用。自体骨移植是最好的，因为它的骨传导和骨诱导属性，但是对于大多数病例，

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