Midterm Development of Ultrasound-unstable Hip Joints After Overhead Traction and Treatment With Tübingen Splint and Fettweis Plaster: A Radiologic Follow-up Analysis Over 5.5 Years

Purpose: The aim of this study was to determine the success rate for treatment of ultrasound unstable hips (type D, III and IV) with Fettweis plaster in terms of a midterm follow-up from the very beginning in the neonatal period until the age of 4 to 8 years. Methods: In total, 69 unstable hips, which were successfully treated with Fettweis plaster and after with a flexion-abduction splint, were included into the study. Hip delvelopment was followed by determining the acetabular index (ACI) on routine pelvic radiographs at the age of 12 to ≤24, 24 to ≤48 and 48 to ≤96 months and the center edge angle on the latter, and classifying both angles according to Tönnis. Results: After initially successful treatment, the first radiograph at the age of 12 to ≤24 months showed 39.1% (n=27) hips with normal findings, 33.2% (n=23) hips with slightly dysplastic findings, and 27.5% (n=19) hips with severe dysplastic findings. Comparison between first and second radiograph showed improvement of the ACI in 9/69 hips and between the second and third time point in 20/69 hips. Overall, 20 hip joints showed deteriorations. Hereby, 16 deteriorations took place after the first radiograph and 4 after the second radiograph. Deteriorations were observed independently of the initial hip type (D, III, and IV). Conclusions: Midterm results indicate that radiologic controls should be provided to detect deteriorations after finishing treatment. ACI and center edge angle are helpful parameters in the assessment of hip joint development in the age range of 4 to 8 years. Level of Evidence: Level III.