Treatment of developmental dysplasia of the hip after failed open reduction

It is difficult to obtain a good result by secondary open reduction if a pr imary open reduction for developmental dysplasia of the hip (DDH) fails. Co mplications such as avascular necrosis of the femoral head and subluxation of the hip are common. In this study, we retrospectively reviewed the cause s of failure of primary open reduction and the final clinical and radiograp hic outcomes of 32 patients: (34 hips) with DDH who underwent repeat open r eduction and other procedures from January 1982 to December 1995. The ages of the patients at the time of the secondary operation ranged from 1.5 to 1 6.5 years (mean, 5.9 yr). The interval from the primary open reduction to t he secondary procedure ranged from 3 dal's to 10 years (mean, 8.9 mo). In m ost cases (30 hips), the position of the redislocated femoral head was Tonn is grade 3 or 4. Avascular necrosis of the femoral head was evident in abou t half of the hips before the secondary open reduction. The most common cau se of failure of the primary operation was a tight inferior capsule and tra nsverse acetabular ligament, which blocked complete reduction. At a mean fo llow-up period of 42 months (range, 24-147 mo) after the secondary operatio n, the radiographic classification was Severin class 1 or 2 in 15 of the hi ps, and Severin class 3 or worse in the remaining 19 hips. Clinically, acco rding to the modified McKay criteria, 18 of the 32 patients (18 hips) had e xcellent or good results, and three patients (four hips) had poor results. In conclusion, the main cause of failure of the primary open reduction of D DH was technical error. We believe that detailed preoperative evaluation is critical for the success of primary open reduction of DDH.