PROPHYLACTIC PINNING OF THE CONTRALATERAL HIP AFTER UNILATERAL SLIPPED CAPITAL FEMORAL EPIPHYSIS

Abstract

Background: The management of the contralateral hip after unilateral slipped capital femoral epiphysis is controversial. The purpose of this study was to determine, with use of expected-value decision analysis, the optimal management strategy—prophylactic in situ pinning versus observation—for the contralateral hip. Methods: Outcome probabilities were determined from a systematic review of the literature. Utility values were obtained from a questionnaire on patient preferences completed with use of a visual analog scale by twenty-five adolescent male patients without slipped capital femoral epiphysis. A decision tree was constructed, fold-back analysis was performed to determine the optimal treatment, and one and two-way sensitivity analyses were performed to determine the effect on decision-making of varying outcome probabilities and utilities. Results: Observation was the optimal management strategy for the contralateral hip given the outcome probabilities and utilities that we studied (the expected value was 9.5 for observation and 9.2 for prophylactic in situ pinning, with a marginal value of 0.3). Increased rates of a late second slip favored prophylactic in situ pinning (the threshold probability was 27%). Risk-taking patients with a high utility for uncomplicated prophylactic in situ pinning favored prophylaxis (the threshold utility was 9.8). Conclusions: The iatrogenic risks of treating a healthy patient or an uninvolved body part rarely outweigh the potential benefits unless the probability of the adverse event is likely and the consequences of the adverse event are very severe. In this decision analysis, the optimal decision was observation. In cases where the probability of contralateral slipped capital femoral epiphysis exceeds 27% or in cases where reliable follow-up is not feasible, pinning of the contralateral hip is favored. For a given individual patient, the optimal strategy depends not only on probabilities of the various outcomes but also on personal preference. Thus, we advocate a model of doctor-patient shared decision-making in which both the outcome probabilities and the patient preferences are considered in order to optimize the decision-making process. Level of Evidence: Economic and decision analysis, Level III-1 (limited alternatives and costs; poor estimates). See Instructions to Authors for a complete description of levels of evidence.