Total hip arthroplasty with structural bone graft of superolateral acetabulum for developmental dysplasia of the hip

Abstract

Objective To assess the mid- or long-term clinical outcomes of the structural bone graft of superolateral acetabulum in total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH). Methods Thirty-three patients with DDH (33 hips) were treated by THA with the structural bone graft of superolateral acetabulum technique between April 2002 and December 2011. There were 28 females and 5 males with the mean age at surgery 54.0±14.5 years (21-76 years). The degree of dislocation was graded preoperatively as Crowe II in 12 patients, Crowe III in 8 patients, and Crowe IV in 13 patients. The following outcomes were assessed, Harris hip score (HHS), the leg-length discrepancy, the height and horizontal distance of center of hip rotation, rate of cup coverage, the coverage ratio of bone graft, periprosthetic osteolysis, bone ingrowth, and cup loosening. Results The average follow-up was 9.3±3.3 years (5-15 years). The HHS improved from 40.9±13.7 preoperatively to 93.6±7.8 at the final follow-up (t=21.483, P=0.000). The leg-length discrepancy decreased from 24.2±17.1 mm pre-operatively to 3.7±3.5 mm at post-operative 3 months (t=6.747, P=0.000). The height and horizontal distance of center of hip rotation decreased from preoperative 45.9±16.0 mm and 42.9±8.7 mm to postoperative 23.8±5.8 mm and 23.6±2.9 mm (t=7.460, P=0.000; t=12.090, P=0.000) at post-operative 3 days, respectively. The cup coverage and coverage ratio of bone graft was 100% and 27.1%±6.9%, respectively. All grafts appeared to be incorporated without evidence of resorption and collapse. The mean time of incorporation was 7.6±2.8 months. The coverage ratio of bone graft >25% have a significantly long time of incorporation than that <25% (9.4±2.3 months versus 6.3±2.4 months, t=5.357, P=0.000). At the final follow-up, all hips showed bone ingrowth fixation of the acetabular cup and stem. Five hips showed osteolysis, two hips in acetabular zone II, three hips in femur zone I and five hips in femur zone VII. The main complications were intraoperative femoral fractures (61%) without neurological damage, nonunion and dislocation. Conclusion The structural bone graft of superolateral acetabulum in THA for DDH can achieve satisfactory mid- or long-term outcomes. The superolateral acetabular deficiency can be reconstructed by bone graft. The bone graft coverage less than 25% is conducive to fusion of bone graft and acetabular bone. However, intraoperative femoral fracture is common complication. Key words: Bone diseases, developmental; Bone transplantation; Arthroplasty, replacement, hip