髋臼假体上移放置对髋关节发育不良全髋关节置换术后下肢长度及功能的影响

The effect of selectively upward placement of acetabular implants on limb length and post-operative function of developmental dysplasia of the hip patients with shortened legs

目的探讨髋臼假体上移放置对伴有患肢短缩的髋关节发育不良全髋关节置换术后下肢长度及功能的影响。方法2008年1月至2013年12月行全髋关节置换术的髋关节发育不良患者26例，男5例，女21例；年龄36-80岁，平均62．7岁。CroweⅠ型12例、Ⅱ型8例、Ⅲ型6例。患肢较对侧均有短缩，平均（10．00±5．07）mm。Harris髋关节评分（42．30±12．84）分，WOMAC骨关节炎指数（59．08±13．84）分。采用TraumaCad软件进行术前设计，确定髋臼假体能获得自身稳定的最小上移幅度。术中根据髋臼骨量适当上移髋臼旋转中心，使髋臼假体获得70％以上的骨性包容。结果全部患者随访6-73个月，平均36个月。末次随访时Harris髋关节评分（91．18±7．09）分，WOMAC骨关节炎指数（9．85±3．75）分。患肢平均延长（9．23±7．54）mm，8例患肢延长肛5mm、5例延长6-10mm、5例延长11-15mm、7例延长〉15mm、1例较术前短缩增加1mm。髋臼假体上移0-5mm10例，患肢延长（6．60±6．72）mm，术后双下肢长度差（-3．70±6．43）mm；上移6-10mm7例，患肢延长（11．90±5．64）mm，术后双下肢长度差（1．71±6．24）mm；上移〉10mm9例，患肢延长（10．11±9．35）mm，术后双下肢长度差（O．56±7．70）mm；三组术后患肢长度变化和双下肢长度差比较均无统计学意义。结论对髋关节发育不良髋臼变异的患者，全髋关节置换术中采用髋臼假体上移放置对下肢长度的恢复无明显不良影响，近期疗效满意。

Objective To investigate the effect of selectively upward placement of acetabular implants on limb length and post-operative function of developmental dysplasia of the hip patients with shortened legs during total hip arthroplasty （THA）. Methods Twenty-six cases of developmental dysplasia of the hip received THA between January 2008 and December 2013, including 12 cases of Crowe type Ⅰ , 8 of Crowe type Ⅱ, 6 of Crowe type Ⅲ. There were 5 males and 21 females with an average age of 62.7 years （range, 36-80 years）. The left hip was involved in 9 cases and the right hip in 17 cases. The preoperative mean Harris score was 42.30±12.84, and the preoperative mean WOMAC score was 59.08_＋13.84 at the last follow-up. The anteroposterior X- ray films and CT scan of the pelvis, anteroposterior and lateral X-ray films of the femur, and TraumaCad analysis were conducted routinely preoperation. More than 70% of the bone-implant interface was covered by appropriate upward distance of acetabular implant. Results The follow-up time ranged from 6 to 73 months （mean, 36 months）. The Harris score improved to 91.18±7.09, and WOMAC score reduced to 9.85±3.75. According to postoperative measurement, affected limb had been lengthened by 0-5 mm in 8 cases, 6-10 mm in 5 cases, 11-15 mm in 5 cases, 〉15 mm in 7 cases, and shortening increased 1 mm in 1 case, but the average lengthening was 9.23±7.54 mm. The upward distance of acetabular implant was 0-5 mm in 10 cases, 6-10 mm in 7 cases and 〉10 mm in 9 cases. The average lengthening was 6.60_＋6.72 mm in patients having 0-5 mm upward distance, 11.90±5.64 mm in patients having 6-10 mm upward distance and 10.11±9.35 mm in patients having 〉15 mm upward distance, showing no significant differ- ence. The leg length discrepancy was -3.70±6.43 mm in patients having 0-5 mm upward distance, 1.71_＋6.24 mm in patients having 6-10 mm upward distance and 0.56±7.70 mm in patients having 〉15 mm upward distance, showing no significant difference. Conclusion The limb length could be improved by selectively upward placement of acetabular implants in developmental dysplasia of the hip patients with anatomically abnormal acetabulum during THA, with reasonable preoperative design and colrective operation.