Metal-on-metal dysplasia cup total hip arthroplasty for hip osteoarthritis secondary to developmental dysplasia of the hip.

Objectives: This study aims to evaluate the clinical and radiological results of metal-on-metal dysplasia cup total hip arthroplasty (THA) for hip osteoarthritis secondary to developmental dysplasia of the hip (DDH).

Patients And Methods: Between May 2009 and October 2011, THA was performed on 27 hips (7 Crowe type II, 9 Crowe type III, 11 Crowe type IV) of 22 patients (2 males, 20 females; mean age 43 years; range 25 to 63 years) with hip osteoarthritis secondary to DDH. All patients were evaluated clinically and radiographically.

Results: Average follow-up period was 34.2 months (range 24-53 months). While mean Harris hip score (HHS) was 43 (range 30 to 72 points) preoperatively, it was 92 (range 87 to 98 points) at final follow-up. Two patients developed sciatic nerve palsy postoperatively. Recurrent dislocation occurred in one patient one year after the operation. Mean cup inclination was 45.6° (range 42°-51°). Heterotopic ossification developed in eight patients. No patient's acetabular and femoral component migrated or subsided significantly. None of the implants was revised.

Conclusion: Early clinical and radiological results of metal-on-metal dysplasia cup THA in DDH are satisfactory.