Have Changes in Treatment of Late-detected Developmental Dysplasia of the Hip During the Last Decades Led to Better Radiographic Outcome?

Abstract

Despite considerable changes in the treatment of of late-detected congenital or developmental hip dislocation (DDH) during the last 50 years, it is unclear whether and to what degree these changes have led to better long-term outcome for the patients. The aims of this study were to see whether decreasing use of skin traction and instead a more aggressive approach to open reduction resulted in (1) reduced use of secondary procedures; (2) improved radiographic appearance of the hips at long-term followup; and (3) changes in the proportion of patients developing avascular necrosis. Two groups of patients were compared retrospectively. Inclusion criteria were patient age older than 3 months and younger than 5 years at the initiation of treatment, no associated anomaly, no previous treatment in other hospitals, and available radiographs from the time of diagnosis to skeletal maturity. Group A consisted of 56 patients (51 girls [91%]; 74 hips) primarily treated during the period 1958 to 1962. Group B comprised 38 patients (36 girls [95%]; 40 hips) treated during the period 1996 to 2002. The mean age at the time of hip reduction was 20 months (SD 9.6) in Group A and 17 months (SD 11.9) in Group B. The mean time in skin traction had decreased from 35 days (SD 12.5) to 11 days (SD 5.7) over the years (p < 0.001). Open reduction was performed in six of 74 hips (8%) in Group A and 15 of 40 hips (37%) in Group B (p < 0.001). The immobilization time in the hip spica had decreased from 9 to 6 months (p < 0.001). The indication for secondary procedures to correct residual dysplasia was center-edge angle < 20° and was similar in both groups. A modified version of the radiographic classification of Severin was used to compare the results. Secondary procedures to correct residual dysplasia were performed in 28 of 74 hips (38%) in Group A and seven of 40 hips (18%) in Group B (odds ratio [OR], 0.35; 95% confidence interval [CI], 0.14-0.89; p = 0.025) At skeletal maturity, the proportion of patients with satisfactory radiographic results (Severin Grades I/II) was larger in Group B (33 of 40 hips [82%]) than in Group A (46 of 74 hips [62%]; OR, 0.35; CI, 0.14-0.89; p = 0.025). Femoral head coverage, assessed as the center-edge angle, was greater in Group B than in Group A (mean 26° versus 22°; CI, 0.8-7.9; p = 0.016). There was no difference in the proportion of avascular necrosis of the femoral head (seven of 74 hips [9%] in Group A and five of 40 [13%] in Group B; OR, 1.4; CI, 0.4-4.6; p = 0.614). The move away from prolonged use of skin traction and toward more frequent open reduction for children with a late diagnosis of DDH appears to result in fewer secondary procedures and a better radiographic appearance of the hip at skeletal maturity. Based on the present results, we cannot conclude whether preliminary traction is needed; this question should be evaluated in future long-term studies with a prospective, randomized design. Level III, therapeutic study.