Long-term results after closed reduction of latedetected hip dislocation: 60 patients followed up to skeletal maturity

Background This retrospective study was undertaken because there is limited knowledge about the long-term results after closed reduction of late-detected hip dislocation. The aims were to evaluate the outcome after skeletal maturity and to find predictive factors for good and poor results.

Patients and methods The material included 60 patients (78 hips, 53 girls) treated during the period 1958-62. The primary treatment was skin traction for 36 (16-76) days. Closed reduction was performed in all hips except 4 that needed open reduction. The mean age at reduction was 20 (4-65) months. Hip spica plaster was worn for 9 (6-20) months. Within 3 years of the start of treatment, derotation femoral osteotomy was performed because of increased femoral anteversion in 35 patients. Later, 28 patients underwent additional surgery on the femur or acetabulum to improve femoral head coverage. Radiographs at the time of diagnosis and during follow-up to skeletal maturity were assessed. The average age of the patients at the most recent follow-up was 26 (15-42) years.

Results The femoral head coverage normalized during the primary treatment and then decreased somewhat during the remaining growth period. The dysplasia of the acetabulum improved markedly during the first year after reduction. It continued to improve, but to a much lesser degree, until 8-10 years of age. A satisfactory radiographic outcome at skeletal maturity (Severin grades I and II) was obtained in 63% of the hips. Early derotation osteotomy of the femur did not improve the outcome. Avascular necrosis of the femoral head occurred in 14% of the hips. Risk factors for unsatisfactory outcome at skeletal maturity were high initial dislocation, steep acetabulum 1 year after reduction, reduced femoral head coverage at age 8-10 years, and avascular necrosis.

Interpretation The specific risk factors and the radiographic outcome—with satisfactory long-term results in nearly two-thirds of the patients—would be valuable for comparison with outcome studies after more modern treatment regimes.