Features June 2011 Issue

MRI of the Knee Often Unnecessary

More than half of patients with knee pain who see an orthopaedic surgeon have had a magnetic resonance imaging (MRI) scan that was unnecessary.

Researchers at Rubin Institute for Advanced Orthopaedics at Sinai

MRI: Study casts doubt on its value in obtaining knee-pain diagnosis and treatment.

Hospital in Baltimore evaluated 108 patients with unilateral knee pain who were referred to two knee surgeons over a three-month period.

The investigators completed a questionnaire for each patient that was designed to determine whether the MRI knee studies, ordered by the patientís primary-care physician, were actually needed to obtain a diagnosis and select a treatment program.

Of the 33 patients who underwent MRIs, 24 scans were classified as unnecessary because it was possible to make the diagnosis based on history, physical examination, and X-rays alone. Of the remaining 75 patients who did not receive an MRI, only four required additional MRI evaluation.

The diagnosis of a kneeís condition typically involves a combination of patient history, physical examination and, often, imaging studies. Although MRI can be helpful in diagnosing a knee problem, cheaper imaging procedures, such as X-ray, are often a reliable substitute.

"MRI is useful in many diagnoses, and can be a cost-effective means of decreasing the need for arthroscopy and its risks when used appropriately," said lead investigator Harpal Singh Khanuja, MD. "However, it is an expensive screening tool, and clinicians need to be up-to-date about the appropriate indications for its use."

Michael Schafer, MD, chairman of the Department of Orthopaedic Surgery at Chicagoís Northwestern University, agreed, claiming that the tendency to overuse MRIs goes back to medical school. "There has been a decrease today in the number of schools, that even offer musculoskeletal education," he said.