Prophylactic femoral varization osteotomy for contralateral stable hips in non-ambulant individuals with cerebral palsy undergoing hip surgery: decision analysis

Abstract

Aim This study was undertaken to determine the need for concurrent prophylactic femoral varization osteotomy (FVO) of contralateral stable hips at the time of hip reconstructive surgery on unstable hips in non-ambulant individuals with cerebral palsy (Gross Motor Function Classification System levels IV and V). METHOD A decision analysis model was constructed that included (1) the probability of unstable hips during observation of the contralateral stable hips, (2) unstable hip rate (subluxation or dislocation rate) after prophylactic FVO or after delayed reconstructive surgery (including FVO) for unstable hips, and (3) complication rates after concurrent prophylactic FVO or after hip reconstructive surgery. The final outcome score was based on pain utility measures. The probabilities of all cases and the utility score were obtained by literature review. RESULTS The decision model favoured concurrent prophylactic FVO for the contralateral stable hips over observation (pain utility measure scores 0.814 vs 0.781). In a one-way sensitivity analysis, the decision model favoured concurrent prophylactic FVO when the unstable hip rate of contralateral stable hips during observation was 27% or over. Concurrent prophylactic surgery also demonstrated higher utility scores than observation when the unstable hip rate after FVO was between 0% and 29%. INTERPRETATION The decision analysis model demonstrated that concurrent prophylactic FVO for a contralateral stable hip in individuals with cerebral palsy undergoing hip reconstructive surgery was beneficial from a medical perspective, which was based on current evidence.