Acute knee injuries in military personnel: A case-control study of the effectiveness of direct-access magnetic resonance imaging in a primary care setting

Aim: To evaluate magnetic resonance (MR) imaging as a direct-access diagnostic tool for primary care physicians. Method: Prospective, case-control study in a Royal Air Force setting. We obtained institutional review board approval and informed consent. Cases consisted of patients with acute knee injury and a physician-ordered MR scan. Controls were matched for gender, age, and knee injury and had MR investigation ordered by an orthopedic specialist. Results: MR imaging cost $341 U.S. dollars per scan. Sixteen patients were enrolled, ages 17 to 44 years, and there were 48 controls. There was a significant intergroup difference for time to MR scan (p < 0.001), and no difference in time to specialist orthopedic assessment (p = 0.39). There was a significant intergroup difference (p < 0.001) in time to return to full fitness. Conclusions: Used as a primary care diagnostic tool and in settings where times to surgery are unacceptably long, direct-access MR imaging significantly decreases the amount of time to definitive treatment for military personnel with acute knee injuries. It may also improve clinical outcomes. MR imaging technology should be made more widely available in military primary care, including during mature combat missions.