计算机辅助定制cage及同种异体颗粒骨植骨重建严重髋臼骨缺损的疗效

Using customized acetabular cages for revision THA with severe bone defects

目的探讨全髋关节翻修术中计算机辅助定制cage重建严重髋臼骨缺损的临床疗效。方法2005年1月至2014年9月因全髋关节置换术后严重髋臼骨缺损行计算机辅助定制cage重建23例（23髋），男8例，女15例；年龄46～79岁，平均64．2岁。骨缺损AAOS分类：Ⅲ型20例，Ⅳ型3例。采用计算机辅助定制技术根据髋臼骨缺损形态设计并制作cage，植入cage及同种异体颗粒骨植骨重建髋臼骨缺损。术后6周、12周、1年及以后每年随访一次，对Harris髋关节评分、术后并发症和再手术率进行评估。放射学评价包括cage位置、移位和植骨愈合情况。结果随访24～120个月，平均66．3个月。Harris髋关节评分从术前（36．2±7．9）分（20±49分）提高至末次随访的（81．8±8．4）分（60～96分），差异有统计学意义（t=23．23，P〈0．001）。定制cage翻修术后髋关节旋转中心基本位于解剖位置。翻修侧髋关节旋转中心水平距离（股骨头中心距耻骨联合的水平距离）与健侧相差（-3．0±6．4）mm（-19～8mm），垂直距离（股骨头中心距双侧泪滴下缘连线的距离）与健侧相差（0．4±2．8）mm（-4．5～5mm）。随访期间无再次翻修病例。x线片未见cage移位，1例可见假体周围2mm环形透光线。22例同种异体颗粒骨骨整合良好，1例可见较明显的骨吸收。术后发生深部感染1例、浅表感染1例，予以冲洗、清创及负压封闭引流治疗；术后脱位1例、可疑臀上神经损伤1例，均予以保守治疗。结论应用计算机辅助定制cage翻修严重髋臼骨缺损，可重建髋关节旋转中心，改善髋关节功能，翻修假体松动率低，近中期疗效满意。

Objective To evaluate the results of computer-aid customized acetabular cages for patients with severe defects. Methods Twenty-three patients （8 males and 15 females） with a massive acetabular defects were involved in the present study from January 2005 to September 2014. The average age was 64.2 years （range, 46-79 years）. According to the American Academy of Orthopaedic Surgeons （AAOS） classification, 20 had AAOS type Ⅲ defects and three had AAOS type Ⅳ defects. The customized cages were individualized to each patient＇s bone defects based on the rapid prototype three-dimensional printed models. The mean follow-up duration was 66.3 months （range, 24-120 months）. The clinical and radiographic outcomes of all patients were assessed at 6 and 12 weeks after surgery and at once yearly thereafter. Harris hip scores were assessed before surgery and at each follow-up. Postoperative radiographs were evaluated for cage position, migration, and graft incorporation. Complications and reoperations were assessed by chart review. Results The mean Harris hip score improved from 36.2±7.9 （range, 20-49） to 81.8±8.4 （range, 60-96）, and there is a significant difference between pre- and post-operation （t=23.23, P〈0.001）. Individualized cus- tom cages resulted in generally reliable restoration of the hip center. The difference of horizontal distance （between the center of each hip and pubic symphysis） between bilateral sides was -3.0±6.4 mm （range,- 19-8 mm）. The difference of vertical distance （between the center of each hip and the line connecting the inferior border of the bilateral tear drop） between bilateral sides was 0.4＋2.8 mm （range, -4.5-5 mm）. No re-revisions had been conducted. None of the cups showed radiographic migration, while one cage was suspected to be loose based on a circumferential 2-mm radiolucent line. Cancellous allografts appeared to be incorporat- ed in 22 of 23 patients. One deep infection and one superficial infection were observed and were treated with irrigation, debride- ment, and vacuum sealing drainage. One dislocation and one suspected injury of the superior gluteal nerve also were observed and were treated conservatively. Conclusion Individualized customized cages appears to provide stable fixation and improve hip scores at short or mid-term follow-up.