髋臼Paproskym Ⅲ型骨缺损重建的中期疗效

Mid-term outcomes of revision hip arthroplasty for severe acetabular bone defects

目的探讨髋臼Paprosky Ⅲ 型骨缺损重建的中期疗效。方法2002年1月至2012年6月，29例（30髋）因假体周围骨溶解、感染等原因导致髋臼Paproskym型骨缺损的患者接受翻修术，男17例，女12例；年龄42～83岁，平均（64．7±2．9）岁；ⅢA型18例（19髋），ⅢB型11例（11髋）。采用钽金属垫块及非骨水泥臼杯11髋、同种异体植骨髋臼加强环及骨水泥臼杯19髋。术后评估髋关节功能及并发症发生情况，摄x线片观察假体松动、假体周围透光线及骨溶解。以假体再翻修为终点，分析Kaplan-Meier假体10年生存率。结果27例（28髋）获得4年以上随访，随访时间4．4～11．8年，平均6．8年。Harris髋关节评分由翻修术前（31．4±5．7）分提高至末次随访的（88．3±3．9）分，差异有统计学意义（t=6．392，P〈0．001）；肢体长度短缩由术前（28．4±10．2）mm恢复至术后即刻（1．4±2．8）mm，差异有统计学意义（t=7．391，P〈0．001）；髋关节旋转中心上移由术前（35．3±6．4）mm恢复至术后即刻（3．2±5．8）rnm，差异有统计学意义（t=9．427，P〈0．001）；髋关节旋转中心均在Ranawat三角内。植入的同种异体骨于术后6个月至2年期间与自体骨整合。无一例发生影像学假体松动。钽金属垫块及非骨水泥臼杯组2例（2髋）在DeLee和ChamleyⅡ区、同种异体植骨髋臼加强环及骨水泥臼杯组3例（3髋）在假体一骨界面出现非连续性透光线，2例（2髋）各有1枚螺钉周围出现透光线，但随访期间无进展。髋臼假体10年生存率为100％，95％置信区间为（0．95，1．00）。结论对髋臼连续性存在、前后柱相对完整的严重髋臼骨缺损（大部分Paprosky ⅢA型）的重建采用钽金属垫块及非骨水泥臼杯，对髋臼连续性破坏、前后柱特别是后柱完整性破坏的髋臼骨缺损（大部分Paprosky ⅢB型）的重建采用同种异体植骨髋臼加强环及骨水泥臼杯重建，可恢复髋关节旋转中心，获得满意的中期临床结果。

Objective To evaluate the mid-term clinical and radiographic outcomes of acetabular revision for Paprosky Ⅲ A or Ⅲ B acetabular bone defects. Methods Thirty consecutive acetabular revisions were conducted with allograft bone trans- plant, metal augment or reinforcement combined with cement or cementless cup in 29 patients with a severe Paprosky Ⅲ acetabu- lar bone defects from January 2002 to June 2012. There were 17 males and 12 females with average age 64.7±2.9 years. Eleven hips had acetabular reconstruction using cementless cup and augment, nineteen hips were revised using allograft bone transplant, acetabular reinforcement ring and cement cup. Hip function of patient was evaluated by Harris score at pre- and post operation. The outcomes of acetabular prostheses and bone grafts were assessed by radiographic analysis. The 10-years components survival rate was assessed by Kaplan-Meier survivorship analysis. Results Twenty-seven patients （28 hips） had a minimum 4-year follow- up, ranged from 4.4 to 11.8 years （6.8 years on the average）. The average Harris score improved from pre-operative 31.4±5.7 to 88.3±3.9 at the final follow-up （t=6.392, P 〈 0.001）. The leg discrepancy was improved from preoperative 28.4±10.2 mm to postop- erative 1.4±2.8 mm （t=7.391, P 〈 0.001）. The hip rotation center was reconstructed from preoperative 35.3±6.4 mm to postopera- tive 3.2±5.8 mm （t=9.427, P 〈 0.001） lateral-toward dislocation to inside Ranawat triangle. The allograft bone was incorporated with the host bone during 6 months to 2 years postoperatively. Radiographic analysis of all 28 hips showed that there was no com- ponent loosening, and among of them, 5 hips had a non-progressive radiolucent line. No screw or cement fracture and no cage dis- placement occurred. There was no moderate or severe bone absorption at the final follow-up. Kaplan-Meier analysis demonstrated that a ten-year component survival rate was 100% （95%CI： 0.95, 1.00）. Conclusion In hip revision surgery, most of Paprosky IIIA acetabular bone defects are characterized by continuous acetabulum and relative intact of anterior and posterior column, which is suitable to take metal augment and cement cup to reconstruct. Most of Paprosky IIIB acetabular bone defects have discon- tinuous acetabulum and severe destruction of anterior/posterior column. Restoration hip rotating center and satisfied midterm out- comes benefit from allograft bone transplant combined with acetabular reinforcement ring and cement cup.