Primary total hip arthroplasty for treating severe developmental dysplasia of the hip.

Objective To evaluate the clinical results of the primary total hip arthroplasty (THA) for treating severe developmental dysplasia of the hip (DDH) and to explore the practicality and operation points.Methods We investigated and analyzed the clinical and X-ray results of 35 severe DDH patients who re-ceived primary THA from March 2002 to June 2008, including 11 males (11 hips) and 24 females (28 hips),with the average age of 52±6.7 years (ranged 45-71 years). According to Crowe classification, 27 patients (31 hips) were classified as type Ⅲ and 8 patients (8 hips) as type Ⅳ. The mean Harris score was 42.5±5.3 pre-operatively. All the patients received non-cemented prosthesis. Results All patients were followed up for average 46 months (1-7 years). The mean Harris score was 86.3±3.4 points at the final follow-up, which had statistic significancy. Among these patients, 33 hips had excellent results, 5 hips had good results and 1 hip had fair results. The rate of excellent and good results was 97.4%. During the follow-up period, there was no radio-lucent line or prosthesis loosening. Two cases suffered acetabuiar fractures during surgery, and were treated with additional screws or structural bone-grafting according to the fracture stability. After 6 weeks,both fractures healed uneventfully. Three patients developed deep vein thrombosis (DVT) and after throm-bolytic therapy, the thrombus disappeared. Heterotopic ossification (Brooker type Ⅰ or type Ⅱ) were found in 5 patients (6 hips), and the rate of beterotopic ossification was 15.4%. One patient suffered femoral frac-ture at the level below the femoral prosthetic tip one year after THA due to injury. Conclusion For the se-vere DDH patients, it's neccesary to make precise measurement and accurate evaluation before primary THA, and do thorough soft tissue releasement during operation, fix the acetabular and femoral prostheses ac-cording to bone character and deal with intraoperative fractures properly. Thus good short-term clinical re-suits can be expected. Key words: Arthroplasty; replacement; hip; Hip dislocation; congenital; Osteoarthritis; hip