恶性骨肿瘤保肢手术后的骨关节返修术

目的 分析四肢恶性骨肿瘤保肢手术后进行返修术的原因及手术治疗经验。方法 1994年1月－1997年12月进行保肢手术后骨关节返修术8例，平均无瘤生存时间8年。主要返修原因是严重的创伤性骨关节炎、骨折、骨吸收。影响返修手术的主要困难是软组织挛缩和肢体短缩。结果 行全髋返修1例，股骨下端长段同种异体骨移植再建3例，在原移植物基础上行全膝关节置换3例，更换髓内钉1例。术前骨扫描结果提示原移植的4例长段同种异体骨已有较活跃的骨代谢，术后病理学检查显示移植骨段存活。术后疼痛症状明显改善，功能满意。结论 保肢手术后的返修术主要原因是植入的异体骨或灭活瘤段发生骨折、关节功能较差。在有良好的软组织覆盖下，应用绞链式可旋转全膝关节假体或长段异体骨复合半限制球轴式表面置换人工膝关节假体可获得较理想的术后功能。

BONE AND JOINT REVISION SURGERY AFTER LIMB SALVAGE PROCEDURE OF MALIGNANT BONE TUMOR

Objective To analyze the indications for revision surgery after limb salvage procedure of malignant bone tumor and summarize the experiences in revision surgery. Methods From January 1994 to December 1997, 8 cases were re operated after primary limb salvage procedure. The average survival period with no tumor occurrence was 8 years. The common causes for the revision were traumatic osteoarthritis, fracture, and bone resorption. The main difficulties in revision were soft tissue contracture and limb discrepancy from limb shortening. Results In this study, there was total hip replacement in 1 case, large segmental allograft for reconstruction of distal femur in 3 cases, total knee replacement upon composite of previously transplanted allograft in 3 cases, removing of intramedullary nail and re internally fixed with intramedullary nail in 1 cases. The isotopic bone scan before the revision showed active bone metabolism in all 4 transplanted segmental allograft. The pathologic study of the transplanted allograft after revision confirmed new bone formation in allograft. The revision procedure reduced the pain, and improved the limb function. Conclusion The main causes of revision surgery after limb salvage procedure of malignant bone tumor are fracture of transplanted allograft segment or devitalized tumor segment, and poor function of the affected joint. Constrained knee prostheses with rotating hinges or semi constrained ball axis resurfacing knee prostheses improve the function of knee joint postoperatively.