Acute peripheral joint injury: cost and effectiveness of low-field-strength MR imaging--results of randomized controlled trial.

ABSTRACT

PURPOSE: To assess prospectively if a short imaging examination performed with low-field-strength dedicated magnetic resonance (MR) imaging in addition to radiography is effective and cost saving compared with the current diagnostic imaging strategy (radiography alone) in patients with recent acute traumatic injury of the wrist, knee, or ankle. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Patients with recent trauma of the wrist, knee, or ankle were randomized across two diagnostic strategies radiography alone (reference group) or radiography followed by a short MR imaging examination (intervention group). Measures of effectiveness included the number of additional diagnostic procedures, time to last diagnostic procedure, and number of days absent from work. Measures of effectiveness were analyzed by using an exact Wilcoxon-Mann-Whitney test. Time to convalescence and quality of life were analyzed by using a t test. Cost analysis was performed from a societal perspective and analyzed by using a t test. RESULTS: Five hundred patients (207 women, 293 men; mean age, 34.8 years) with acute injury of the wrist, knee, or ankle were randomized. In the intervention group, quality of life for patients with knee injuries was significantly higher during the first 6 weeks, and time to completion of diagnostic work-up was significantly shorter (mean, 3.5 days for intervention group vs 17.3 days for reference group). The number of additional diagnostic procedures was significantly lower in the intervention group versus the reference group (nine vs 35, respectively) for patients with knee injuries. Patients with knee injuries showed the largest difference in costs (intervention group, 1820 [$1966]; reference group, 2231 [$2409]) owing to a reduction in productivity loss. Costs were higher in patients with wrist injuries and almost equal in patients with ankle injuries. All cost differences, however, were not significant. CONCLUSION: Compared with radiography, MR imaging in patients with acute wrist or ankle injuries is neither cost saving nor effective in expediting diagnostic work-up or improving quality of life. In patients with knee injuries, a short MR imaging examination shortens the time to completion of diagnostic work-up, reduces the number of additional diagnostic procedures, improves quality of life in the first 6 weeks, and may reduce costs associated with lost productivity.