Protocolised MRI as an Adjunct to CT in the Diagnosis of Femoral Neck Fracture in High Energy Ipsilateral Femoral Shaft Fractures - a Breakeven Analysis

Abstract Background In high-energy femoral shaft fractures, ipsilateral femoral neck fractures can be missed by conventional trauma computed-topography (CT) imaging, resulting in increased treatment costs and patient complications. Evidence suggests that a rapid, limited-sequence pelvis and hip magnetic resonance imaging (MRI) protocol can identify these occult fractures and be feasibly implemented in the trauma setting. This study aims to analyse the economic viability of implementing a such an MRI protocol for all high-energy femoral shaft fractures. Methods We used an adapted break-even economic tool to determine whether the costs of an MRI protocol can be offset by cost-savings achieved through prevention of missed fractures (thus avoiding prolonged inpatient admission, re-operation and implant costs). Sensitivity analyses were performed to demonstrate the reliability of the economic modelling across a range of assumptions. Results Assuming a baseline of hip fractures missed on CT of 12%, an MRI cost of £129 and cost of treating each missed hip fracture of £2633.5, the equation yielded a breakeven rate of 7% and absolute risk reduction (ARR) of 5%, indicating that for every 100 femoral shaft fractures, MRI would need to diagnose 5 of the 12 missed hip fractures to be economically viable (NNT=20). Economic viability was maintained even at double the cost of MRI, while increasing the cost of treating each complication served to reduce the ARR further, increasing cost effectiveness. Conclusion A rapid, limited-sequence MRI protocol to exclude occult ipsilateral hip fractures in all femoral shaft fractures would be an economically justified measure.