【专题文献】之人工髋关节置换——下肢假体周(7)

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

development of the Ogden plate, which uses a combination of cable and screw fixation proximally and conventional screw fixation distally.

螺钉固定联合环扎术并联合锁定系统仍然是争议的。联合使用可以有更好的钢板固定效果，因此有更稳定的结构，但是反对者声称由锁定装置带来的好的把持力，使环扎术的使用不是那么必须，且反对者认为他们是危险的，因为可以导致应力升高。

通常的，钢板固定到骨上，意见一致的是螺钉，环扎术或捆绑带在独立应用时被证明是无效的。联合应用显示出好结果。Tsiridis等显示在使用Dall-Miles钢板，本质上是Ogden钢板的进化物，并且联合使用环扎带和螺钉固定近端，传统螺钉固定远端，有一个好结果。

Special attention should be given to the proximal screw fixation. In this case the use of uni-cortical screws is recommended around the stem of the implant and bi-cortical screws below this level. The more proximal the periprosthetic fracture the more challenging the fixation is. The prosthesis and the cement mantle restrict the options for screw and plate placement and insertion of the screws can fracture the cement or act as stress risers, altering the biomechanical properties of the cement and leading to instability and interference with the prosthesis/bone interface with consequent loosening and long term osteolysis.

应特别注意近端螺钉固定，在此案例下，使用单皮质螺钉推荐用于假体干部，而双皮质螺钉用于假体之下。假体周围骨折更靠近端，内固定越有挑战性。假体和骨水泥封套限制了螺钉选择和钢板位置，插入螺钉能导致骨水泥骨折或使应力升高，改变了骨水泥的生物力学属性，导致假体骨界面的不稳定和干扰，随后出现松动和长期的骨溶解。

In type 2, the unhappy fractures, where the prosthesis is affected or there is evidence of loosening, revision of the prosthesis should be undertaken. When revising a femoral stem in the presence of a periprosthetic fracture, most authors advocate the use of long stems. A long stem can give good results when bone loss is proximal to the isthmus. Larson at al state that cortical perforations and femoral fractures should be bypassed by at least 2 femoral diameters.16 Both cemented and uncemented implants can be used (Figures 3 and 4). The latter depend on good fixation in the femoral diaphysis for initial stability.17 A short stem can be used but it is generally accepted that the fracture should be bypassed distally by at least 5e10 cm. Overall, uncemented porous implants have given the best results.18

在2型，令人烦恼的骨折，假体受影响或有松动的证据，应该进行假体的翻修。当在假体周围骨折的情况下对股骨假体进行翻修，很多作者倡导使用长假体。当骨丢失位于近端到峡部这一区域，一个长的假体干能带来好结果。Larson等表明，假体长度应该通过皮质穿孔和股骨骨折处至少两个股骨直径。骨水泥型假体和非骨水泥型假体都可以使用（图3和图4）。后者依赖于股骨干部良好的固定，以得到初始稳定性。短的假体干可以使用，但是它通常只在假体可以超过骨折端5

－10cm时才可接受。总体而言，非骨水泥多孔假体有最好的效果。

图3

图4