全髋翻修术后假体脱位的预防

目的：探讨采用后方关节囊重建方法对行后外侧入路全髋翻修术后假体脱位的防治作用。方法：本组45例（47髋）经后外侧入路行全髋翻修术的患者，男20例，女25例；平均年龄65岁（55-78岁）。术中将后方关节囊与外旋肌群分别重建固定于前上方原先切开的关节囊断端和大转子顶端的软组织处，回顾性分析术后假体脱位率及脱位的风险因素。股骨假体和髋臼假体均翻修29例（31髋），更换内衬5例（5髋），髋臼、股骨翻修的分别是10例（10髋）和1例（1髋）。第1次翻修的有29例（30髋），第2次翻修的有15例（16髋），第3次翻修的有1例（1髋）。X线评估包括翻修前后下肢长度，髋臼位相，股骨偏心距、前倾角和假体松动。临床功能评价采用Harris评分。结果：45例均获随访，平均随访时间2．7年，除1例感觉前方不稳外，无髋关节感染及脱位发生，该例X线片示髋臼假体过度前倾但无脱位发生。术后所有患者双下肢基本等长，髋臼外展角及前倾角、股骨偏心距和前倾角基本恢复至初次手术前水平。髋臼、股骨假体发生松动各1例。髋关节功能Harris评分由术前平均（49.13±15．53）分升至末次随访的平均（83．59±6.93）分（P〈0．05）。按Harris功能评分标准：优36髋，良5髋，可5髋，差1髋。结论：在假体安放正确、软组织张力恢复满意基础上，后方关节囊及外旋肌群重建有助于降低后外侧入路全髋翻修术后假体脱位的发生率。

Prevention of prothesis dislocation after the revision of total hip arthroplasty

Objective: To explore the role of reconstruction of the posterior capsule and external rotators in prevention of postoperative dislocation in total hip arthroplasty revision following the posterolateral approach. Methods: Forty-five patients(47 hips)with the mean age of 65 years(55 to 78 years)of failed total hip arthroplasty were revised following the posterolateral approach. Posterior capsule was sutured to the anterosuperior portion of the capsule from where it had been detached,and the external rotators were then reattached to the soft tissue at the tip of the greater trochanter using 1.0 silk suture in surgery. The dislocation rate and risk factors were reviewed retrospectively to determine if closing the posterior capsule resulted in fewer dislocations. The femoral prosthesis and acetabular prosthesis were revised in 29 patients(31 hips),the liner was exchanged in 5 patients (5 hips),and the acetabular prosthesis or femoral components were revised in 10 patients(10 hips) and one patient(one hip) respectively. The procedure was the patient's first revision in 29 patients(30 hips),the second revision in 15 patients (16 hips),and the third revision in one patient(one hip). Radiographic evaluation included lower limb discrepancy,acetabular phase,femoral offset,anteversion angle,prosthetic loosening before and after revision. Function evaluation based on Harris score system. Results: All patients were followed up with an average of 2.7 years. None of the patients sustained dislocation or infection,except one patient felt the anterior instability but without dislocation,X-ray revealed the acetabular component was in excessively anteversion. Lower leg discrepancy,acetabular abduction,anteversion femoral offest and collodiaphyseal angle were restored to normal level after operation on the basis of X-ray. One of the acetabular components and one of the femoral components were loose without dislocation. The Harris hip score improved from(49.13±15.53) points preoperatively to(83.59±6.93)points at the final follow-up(P<0.05). According to Harris functional evaluation,36 hip got an excellent result,5 good,5 fair and 1 bad. Conclusion: The historically high dislocation rate with the posterolateral approach for total hip arthroplasty revision can be reduced by careful soft tissue balancing,correction of implant alignment,meticulously closure of the posterior capsule,and reattaching the external rotators.