Cost-Effectiveness of Preoperative Spinal Imaging Before Total Hip Arthroplasty

Background: The risk of instability, dislocation, and revision following total hip arthroplasty (THA) is increased in patients with abnormal spinopelvic mobility. Seated and standing lateral lumbar spine imaging can identify patients with stiff/hypermobile spine (SHS) to guide interventions such as changes in acetabular cup placement or use of a dual-mobility hip construct aimed at reducing dislocation risk. Methods: A Markov decision model was created to compare routine preoperative spinal imaging (PSI) to no screening in patients with and without SHS. Screened patients with SHS were assumed to receive dual-mobility hardware while those without SHS and nonscreened patients were assumed to receive conventional THA. Cost-effectiveness was determined by estimating the incremental cost-effectiveness ratio. Effectiveness measured as quality-adjusted life years (QALYs), with $100,000 per additional QALY as the threshold for cost-effectiveness. Sensitivity analyses were performed to determine the robustness of the base-case result. Results: The screening strategy with PSI had a lifetime cost of $12,515 and QALY gains of 16.91 compared with no-screening ($13,331 and 16.77). The PSI strategy reached cost-effectiveness at 5 years and was dominant (ie, less costly and more effective) at 11 years following THA. In sensitivity analyses, PSI remained the dominant strategy if prevalence of SHS was >1.9%, the cost of PSI was <$925, and the cost of dual-mobility hardware exceeded the cost of conventional hardware by <$2850. Conclusion: Screening patients for SHS prior to THA with PSI is both less costly and more effective and should be considered as part of standard presurgical workup.