X-Ray Often Better and Cheaper than MRI in Knee Diagnostics

A weight-bearing X-ray is a better diagnostic tool and much less expensive than the MRI typically prescribed for patients with knees affected by osteoarthritis, according to a recent study. A patient’s medical history and a routine physical should be the starting point for a primary-care physician, followed by basic diagnostics.

"MRIs are being used in excess. Many doctors no longer talk to or examine their patients. Instead, they are going right for the technology," said Wayne Goldstein, MD. Dr. Goldstein, lead author on the study, is a clinical professor of orthopedics at the University of Illinois at Chicago College of Medicine and chairman of the Illinois Bone and Joint Institute.

"This is another example of over-utilization of the health-care system. It has become easier to go for the high-cost imaging. On average, an X-ray can cost less than $150, while an MRI can cost around $2,500". Medical imaging now accounts for 10%-15% of Medicare payments to physicians, compares with less than 5% only 10 years ago.

In 2008, Medicare will reimburse doctors more than $400 per MRI. By contrast, a 4-view X-ray which effectively reveals osteoarthritis and is routinely used by most orthopaedic surgeons, reimburses doctors just over $43. It is estimated that these MRI costs will continue to row at an annual rate of 20% or more in 2008. In the United States more than 533,000 total knee replacements were performed in 2005, primarily because of severe pain, swelling of stiffness of the knee caused by osteoarthritis.

A random sample of 50 knee arthroplasty patients found that 32 of the 50 had had a knee MRI within 2 years before surgery, ordered by their primary-care or orthopedic physician. The MRI did not produce any diagnostic information which could not have been provided by an X-ray, and more than 50% did not have any X-rays before surgical consultation.

"There are some indications for MRI, such as suspicion of avascular necrosis [in which blood loss to the area causes bones to break down, something which may not be seen on early X-rays], but that is not a common condition," Dr. Goldstein said. Dr. Goldstein and his co-authors believe that the main reason for this over-utilization of the MRI is a lack of education on this diagnostic technique, especially with family and primary-care physicians.

Dr. Goldstein added, "We fix this problem through educating physicians on the appropriate use of MRIs. We also need to educate our patients. Virtually every adult experiencing a knee problem should first have an appropriate set of X-rays before considering an MRI, which has been marketed as the premier diagnostic tool, so patients often come into the office expecting, even demanding, an MRI. Physicians need to look at why they are ordering an MRI and consider whether it is truly necessary."

The study was presented at the 75th Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in March, 2008.

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