Strict Guides Could Reduce Knee Surgery Medical Costs By John Cramer Health care costs associated with knee replacement surgery amount to about $2 billion annually nationwide. But a recent Hopkins study has found that these expenses could be reduced by one-fourth if stricter guidelines are used to determine which patients should have one or both knees replaced at the same time. The study results, reported recently at the American Academy of Orthopedic Surgeons' annual meeting in Orlando, Fla., found that savings would amount to 100 percent of the cost of the unnecessary second-knee replacements and up to 50 percent of the cost of separate knee replacements that would be performed instead in one procedure. Certain patients with mild X-ray findings and symptoms of arthritis who are having one knee replaced should not have both knees replaced at the same time because they are unlikely ever to need the other replacement, said Michael Mont, the study's lead author and assistant professor of orthopedic surgery, and David Hungerford, the study's senior author and professor of orthopedic surgery, both at the School of Medicine. Certain patients with moderate X-ray findings and symptoms probably also should not have the second knee replaced simultaneously, they concluded. Patients with severe X-ray findings and severe symptoms probably should have both knees replaced at the same time because the other knee is likely to need replacing within about two years. "This finding will be somewhat controversial and warrants further research," Dr. Mont said, "because mortality and morbidity rates for patients receiving two replacements at the same time vary greatly in many studies." Using stricter clinical and radiographic guidelines would reduce by 40 percent the total number of knee replacements. The reduction would include a 20 percent cut in the number of unnecessary second-knee replacements and a 20 percent cut in the number of separate operations on patients who should have both knees replaced at the same time. The study followed 185 patients who had a knee replacement between January 1980 and November 1983. The subjects were evaluated on average 10 years after their replacement. The study found that 93 percent of the subjects with moderate or severe symptoms and severe X-ray findings needed the other knee replaced, but that only 20 percent with moderate symptoms and X-rays and 9 percent with mild symptoms and X-rays needed the other knee replaced. "I've always believed there should be stricter guidelines adhered to concerning the need or lack of need for second knee replacements," Dr. Mont said.