Knee MRI Primary Care Ordering Practices for Nontraumatic Knee Pain: Compliance With ACR Appropriateness Criteria and Its Effect on Clinical Management.

Purpose: To evaluate the appropriateness of MRI ordering practices and their effect on clinical management for nontraumatic knee pain at the primary care clinics of a large public urban hospital.

Materials And Methods: In all, 196 consecutive MRIs for nontraumatic knee pain ordered from primary care clinics in a large public urban hospital over an 18-month period were studied. ACR Appropriateness Criteria (AC) scores for nontraumatic knee pain were retrospectively calculated from medical record reviews. The record was also reviewed to assess whether knee MRI changed clinical management. Knee osteoarthritis grading was performed. Tests were performed for differences in age, body mass index (BMI), gender, and ethnicity among appropriate and inappropriate MRIs.

Results: Of the MRIs, 57% (108 knees) had "usually appropriate" (ie, 7-9) and 43% (8 knees) had "usually not appropriate" (ie, 1-3) AC scores (P > .1). Clinical management was changed in 26% of knees with "usually appropriate" and 20% of knees with "usually inappropriate" scores (P < .05), and 70% of the knees with "usually appropriate" and 61% of the knee with "usually not appropriate" scores had moderate to severe osteoarthritis. Age, BMI, gender, and ethnicity had no significant effect on AC scores.

Conclusion: In patients referred from primary care for MRI for nontraumatic knee pain, adherence to AC was low. Additional focus on reducing "appropriate" studies that do not impact clinical management (eg, cases with radiographically evident moderate to severe osteoarthritis) is also warranted.