Cost-effectiveness analysis of free vascularized fibular grafting for osteonecrosis of the femoral head.

Management of symptomatic pre-collapse osteonecrosis of the femoral head continues to be controversial. Patients are often young and active, therefore hip-preserving procedures such as free vascularized fibular grafting (FVFG) have been developed to relieve pain and restore function, thereby delaying or preventing the need for joint arthroplasty. This study compared the cost-effectiveness of FVFG to total hip arthroplasty (THA) in the young adult. A Markov decision model was created for a cost-utility analysis of FVFG compared to THA. Outcome probabilities and effectiveness, expressed in QALYs gained, were derived from existing literature. Principal outcome measures included average incremental costs, effectiveness, and net health benefits. Multivariate sensitivity analysis was used to validate the model. THA resulted in a greater average incremental cost (+$5,933) while at a lower average incremental effectiveness (-0.15 QALY) compared to FVFG. On average, THA gained 22.08 QALYs at a cost-effectiveness (C/E) ratio of $1026/QALY, whereas FVFG gained 22.23 QALYs at a C/E ratio of $752/QALY. Threshold sensitivity analysis determined that the yearly all-cause probability of revision for FVFG would have to be more than three times greater than THA before THA became more cost-effective. Free vascularized fibular grafting is a more cost-effective procedure to treat osteonecrosis in certain populations. Markov decision analysis accounts for the impact of treatment strategies over the lifetime of a patient cohort. These findings can inform clinical decision making in the absence of universally accepted management strategies.