ObjectiveTo evaluate the effectiveness of the total hip arthroplasty (THA) for severe development dysplasia of the hip (DDH) in adults. MethodsBetween July 2007 and January 2013, 25 patients (27 hips) with severe DDH underwent THA with cementless prosthesis. There were 10 males (11 hips) and 15 females (16 hips) with an average age of 38.6 years (range, 21-57 years). The left hip was involved in 10 cases, the right hip in 13 cases, and bilateral hips in 2 cases. There were 8 cases (9 hips) of Crowe type III and 17 cases (18 hips) of Crowe type IV. The main clinical manifestations were unilateral or bilateral hip pain, claudication, and limited motion of the hip. All patients had leg discrepancy with a length difference of (4.9±0.8) cm. Harris score was 32.7±2.9. ResultsAll patients obtained primary healing of incision; no infection, dislocation, periprosthetic fracture, and lower extremity deep venous thrombosis occurred. All patients were followed up 1-5 years (mean, 3.7 years). Pain relief of the hip was obtained. The motion of the hip was improved obviously. At last follow-up, the length difference between lower limbs was (1.5±0.3) cm, showing significant difference (t=36.703,P=0.000) when compared with preoperative one. Normal gait was observed in the others except 3 cases having mild claudication. Harris score was 89.6±3.2, showing significant difference (t=-65.498,P=0.000) when compared with preoperative one. The X-ray films showed bone union of the acetabular structural bone graft and femoral osteotomy ends, and the union time was 3-5 months (mean, 4.6 months). No complication occurred as follows:dislocation, infection, prosthesis loosening or subsidence, and heterotopic ossification. ConclusionTHA in the treatment of severe DDH in adults can obtain satisfactory short-term effectiveness, but long-term effectiveness needs further observation.