防内突加强杯用于髋臼侧骨缺损翻修的临床研究

Acetabular revision using an anti-protrusion cage in patients with periprosthetic acetabular bone loss

目的探讨影响防内突加强杯髋臼翻修假体生存时间的危险因素。方法对2002年1月至2010年6月使用防内突加强杯进行髋臼翻修的患者进行回顾性分析。有效随访病例40例40髋，男16例、女24例；手术时年龄22-77岁，平均60．3岁；随访时间12-82个月，平均39．2个月。骨缺损AAOS分型C型29例，D型11例；Paprosky分型ⅢA型29例，ⅢB型11例。采用多因素回归分析评估性别、年龄、骨缺损分类、髋臼旋转中心上移和外移尺度、臼杯外展角、臼杯固定方式（单纯经翼固定和经翼联合经髋臼螺钉固定）、植骨方式及臼杯类型与加强杯失败（松动及再翻修）的相关性。结果末次随访时Harris髋关节评分平均（74．5±15．4）分。2例因松动而翻修，2例出现明显的放射学松动伴疼痛症状。髋臼旋转中心上移、臼杯外展角及臼杯固定方式与加强杯失败相关。当加强杯上移8．5mm或外展角大于53．5°时，加强杯失败风险加大；使用经翼联合经髋臼螺钉固定者加强杯失败风险降低。结论防内突加强杯可用于髋关节置换术后髋臼侧严重骨缺损的翻修，但术后中短期仍存在较高的臼杯失败风险。重建时应尽量靠近真臼水平，适当减小臼杯外展角，使用经翼联合经髋臼螺钉固定。

Objective To lnvest^gate the risk tactors related to the survival time oI anti-protrusion cage in acetabular revision. Methods Data of 40 patients who had received acetabular revision using anti- protrusion cages between January 2002 and June 2010 were retrospectively analyzed. There were 16 males and 24 females, aged from 22 to 77 years （average, 60.3 years）. All patients were followed up for 12 to 82 months （average, 39.2 months）. According to the AAOS classification, there were 29 cases of type C and 11 cases of type D; while according to the Paprosky classification, there were 29 cases of type Ilia and 11 cases of type m B. The multiple regression analysis was utilized to investigate the relationships between different factors and anti-protrusion cage failure. The corresponding factors included gender, age, bone loss classifica- tion, superior or lateral migration of acetabular center of rotation, abduction angle, fixation manners （simple flange fixation or flange fixation plus transacetabular screw fixation）, bone grafting techniques and cup type. Results At final follow-up, the average Harris score was 74.5±15.4. Two patients received rerevision due to prosthetic loosening. Obvious radiological loosening of prosthesis combined with pain was found in 2 cases. The statistical analysis indicated that superior migration of aeetabular center of rotation, abduction angle and fixation manners were correlated with cup failure, especially when the superior migration was more than 8.5 mm or the abduction angle was larger than 53.5°. Flange fixation plus transacetabular screw fixation could reduce risk of cup failure. Conclusion There is a higher cup failure risk in acetabular revision using an anti-protrusion cage for patients with serious bone defect. However, implanting cup at the level of the true acetabulum as far as possible, decreasing abduction angle properly and using flange fixation plus transac- etabular screw fixation can reduce cup failure risk.