Radiographs Are the First and Best Screening Tool for Diagnosing Knee Pain, Study Finds

    Knee pain is common among Americans age 40 and up, accounting for 1 in 17 physician visits annually.

    Although magnetic resonance imaging (MRI) is an important tool to help diagnose knee injuries such as torn knee ligaments and cartilage, plain radiographs remain the best first-line screening tool for knee pain from osteoarthritis (OA), according to a study in the September issue of the Journal of American Academy of Orthopaedic Surgeons.

    Whether a patient will need surgery for knee pain depends on the extent of the OA. "If an X-ray shows that a person has significant arthritis, the MRI findings – like a meniscus tear – are less important because the amount of arthritis often dictates the treatment,” says Muyibat Adelani, MD, an orthopaedic surgeon with Washington University's Department of Orthopedics and lead author of this study.

    “Patients (older than age 40) should always get a standing X-ray before getting an MRI to screen for knee pain."

    The study looked at 100 MRIs of knees from patients age 40 and up and found that:

    • The most common diagnoses were OA (39%), and meniscal tears (29%)
    • Nearly 1 of 4 MRIs was taken prior to the patient's first having obtained a weight-bearing X-ray,
    • Only half of those MRIs obtained prior to meeting with an orthopaedic surgeon actually contributed to a patient's diagnosis and treatment for OA.

    "Patients should always get weight-bearing X-rays before getting an MRI because MRIs are not always needed to diagnose knee problems," says Dr. Adelani.

    In cases in which arthritis is suspected, weight-bearing X-rays often are more than enough for surgeons to complete the diagnosis and treatment plan. An appropriately timed consultation with an orthopaedic surgeon can be more cost-effective than first obtaining MRI scans.