The effect of selectively upward placement of acetabular implants on limb length and post-operative function of develop-mental dysplasia of the hip patients with shortened legs / 中华骨科杂志

ABSTRACT

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, in?cluding 12 cases of Crowe typeⅠ, 8 of Crowe typeⅡ, 6 of Crowe typeⅢ. 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 Har?ris 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 im?plant. 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. Con?clusion 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 corrective operation.