6 compared with 12 weeks treatment in the von Rosen splint is sufficient for Barlow and Ortolani positive hips: a comparative study of 237 neonates

BACKGROUND AND PURPOSE: At our institution, newborns with Barlow or Ortolani positive hips have been treated for 12 weeks with the von Rosen abduction splint until 2012 when the treatment length was halved. We investigate whether acetabular development at 12 months of age and complications differ between hips treated with the von Rosen splint for 6 compared with 12 weeks. PATIENTS AND METHODS: 99 patients were included in the 6-week program and 138 patients in the 12-week program. We measured the acetabular index (AI) on standard anteroposterior pelvic radiographs taken at 12 months of age. Medical records were reviewed for complications and additional treatments until age 12 months. We used non-inferiority testing with an equivalence margin of 1° with a 95% confidence interval (CI) to compare the 2 groups. RESULTS: The mean AI at 12 months in the 6-week group was 25° (CI 24–26) compared with 25° (CI 25–26) in the 12-week group. Non-inferiority was demonstrated for the 6-week program: –0.2° (CI –1.1 to 0.7). In the 6-week group, 8 patients received additional treatment, including 1 hip dislocation that occurred between 6 weeks and 3 months. There were no additional treatments or complications in the 12-week group. CONCLUSION: AI was equal at 12 months of age for patients treated for 6 compared with 12 weeks in the von Rosen splint. The hip dislocation which occurred indicates that follow-up around 3 months of age is indicated.