【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

Revision of a prosthesis is challenging and more so in the presence of a periprosthetic fracture. The removal of the old prosthesis and cement requires great care as it can lead to further bone loss, development of a new fracture or extension of the existing one. The surgeon is usually left with significant bone loss and poor remaining bone stock. There are various techniques to overcome these problems, such as the use of cortical onlay grafts. These are usually hemi-cylindrical diaphyseal or cortical fibular allografts, which are fixed to the host bone by circumferential wires. The aim is to provide structural support to the femur by replacing uncontained non-circumferential femoral defects, reducing stress risers and speeding up the healing process.

假体的翻修是挑战性的，特别是在假体周围骨折的情况下。取出旧的假体和骨水泥，需要极大的小心仔细，因为这能导致进一步骨丢失，进展成一个新的骨折或使原先骨折的范围扩大。外科医生通常会留下显著的骨丢失和较差残余骨量。有不同的技术来应付这些问题，如使用外置皮质骨移植。通常使用半环形骨干或腓骨干皮质骨同种异体骨移植，可以使用环形钢丝将此固定到宿主骨。目的是，通过置换非包容的非环形的股骨缺损，减少应力升高和加速愈合进程，提供股骨以结构支撑。

Another technique is impaction grafting, which is usually reserved for severe osteolysis. Firstly, the proximal femur is re-constituted forming a cortical scaffold or containment created using wires, plates or meshes or a combination. Then bone graft is impacted into this tube. Once completed, the reconstructed bony tube can accommodate the femoral component. This technique can also be applied to acetabular defects when compressed graft is used to fill the defect followed by insertion of either a cemented or cementless acetabular component.19

另一种技术是打压植骨，这通常应用于严重骨溶解。首先，股骨近端重新组合后形成皮质支架，或使用钢丝，钢板或钛网或联合使用而得到的包容。然后移植骨被打压进该管道。一旦完成，重建的骨管能适应于股骨假体。该技术也能用于髋臼缺损，使用打压的移植物去填充插入骨水泥型或非骨水泥型假体后形成的缺损。

If a patient is not fit for such a major procedure, there are a few more options available. If the patient is of average functional demand, or if definitive surgery may be possible in the future, in a happy hip external fixation can be considered. If the patient has low functional demand and a loose prosthesis, then a Girdlestone procedure can be considered.

Finally, if the defect is very extensive, using a mega-prosthesis, such as are used after tumour resection, can be considered. The femur is osteotomised just below the level of abnormal bone stock and the prosthesis is fixed to the distal diaphysis. The abductor mechanism is then attached to the mega-prosthesis. Satisfactory results with an average Harris hip score of 71 have been reported by Klein et al. 20

In PPFs around the hip most attention is focussed on the femoral component as periprosthetic fractures around the acetabulum are extremely rare, but they are potentially life threatening. Acetabular fractures most frequently occur intraoperatively, but they are also associated with loosening or severe osteolysis around the acetabular component. Obviously loose sockets should be revised.

如果病人不适合这样的大型操作，那么可得的选择很少。如果病人的功能要求是平均水平，或如果在未来最终手术可能会施行，对于一个稳