Radiological long-term follow-up up to 12 years of initially ultrasound unstable hip types D, III and IV after treatment with the Tübingen splint worn as a plaster

INTRODUCTION: The treatment of ultrasound unstable hips with the Tübingen splint is currently under discussion. However, there is a lack of long-term follow-up data. This study presents to the best of our knowledge first radiological mid-term to long-term data of the successful initial treatment with the Tübingen splint of ultrasound unstable hips. MATERIALS AND METHODS: From 2002 to 2022 the treatment of ultrasound unstable hips type D, III and IV (age ≤ 6 weeks, no severe limitation of abduction) with the Tübingen splint worn as a plaster is evaluated. Based on data derived from routine X-rays during the follow-up period, a radiological follow-up (FU) analysis until the age of 12 years was performed. The acetabular index (ACI) and center–edge angle (CEA) were measured and classified according to Tönnis as normal findings (NF), slightly (sliD) or severely dysplastic (sevD). RESULTS: 193 of 201 (95.5%) unstable hips could be successfully treated showing normal findings with an alpha angle > 65°. The few patients showing treatment failures were successfully treated applying a Fettweis plaster (human position) under anesthesia. The radiological FU of 38 hips showed a favorable trend with increase of normal findings from 52.8% to 81.1% and decrease of 38.9% to 19.9% of sliD respectively 8.3% to 0% of sevD hips. The analysis of avascular necrosis of the femoral head showed 2 cases (5.3%) of grade 1 according to Kalamchi and McEwen, which were improving over time in the further course. CONCLUSIONS: The Tübingen splint as alternative to replace a plaster has proven a successful therapeutic option for ultrasound unstable hips type D, III and IV with favorable and over time improving radiological parameter up to the age of 12 years.