Total Hip Arthroplasty Requiring Subtrochanteric Osteotomy for Developmental Hip Dysplasia 5- to 14-Year Follow-Up With Analysis of Short- and Long-Term Failure Modes

Total hip arthroplasty in 20 consecutive patients with developmental dysplasia of the hip requiring femoral osteotomy for soft tissue decompression and impingement prevention was reviewed at an average 8.2 years (5-14) of follow-up. All osteotomies were transfixed by the S-ROM hip stem. Interval Harris hip scores and radiographs were performed. Kaplan-Meier survivorship analysis was performed using revision as an end point. The 20 patients (23 hips) had an average age of 43 years (17-67); body mass index, 26.4 (21-33); and femoral anteversion, 56° (15°-90°). The Crowe classifications were as follows: type I-4, type II-3, type III-5, and type IV-10. Osteotomy resection averaged 32 mm (0-70 mm); average acetabular size was 47 mm (40-55 mm). Average pre- to postoperative Harris hip score was 42 to 82. All osteotomies healed (1 demonstrated persistent asymptomatic lateral radiolucency). Significant difference between pre- and postoperative range of motion for extension (P = .0074), flexion (P = .003), and abduction (P = .0012) was noted. Improvement of adduction, internal rotation, and external rotation was not significant. A total of 17.4% (4 of 23) required revision at an average of 4 years (range, 1-8 years) postoperatively. Survivorship was 74.9% at 14 years. Failure modes included polywear osteolysis in 3 (13%) and acetabular loosening (manufacturer recall) in 1 hip (4%). Dislocation occurred in 4 hips (17.4%); treatment: closed reduction in 2 and open in 2 (average time to dislocation, 9.5 months; range, 0.6-36). Two hips (8.6%) with complete acetabular radiolucencies, 6 hips (26.1%) with eccentric polyethylene wear (mean, 3.4 mm), and 2 (33%) with osteolysis are under observation.