Rethinking a Common Knee Surgery
Relieving pain and restoring motion are the major reasons someone undergoes knee surgery. But a new study shows one type of operation—a meniscectomy—often leads to a painful, unstable knee. It follows on the heels of a larger study that indicated this kind of surgery can increase cartilage damage afterwards, leading to arthritis.
A meniscectomy by itself is not that big a deal, usually done through tiny incisions around the kneecap. The goal is to repair a meniscus, a pad of tissue that sits in the middle of the knee joint, between the upper leg bones and lower leg bones. It acts as a shock absorber, cushioning the bones from rubbing against one another. There are two of these pads. They can get ripped or torn when the knee suddenly twists to the side, as it can when a runner changes direction sharply. This often happens to young athletes. But rips can happen to older people, too, as part of normal wear and tear on the joint.
If the tear is really small, it typically heals on its own, with the help of a brace and some physical therapy. But with longer tears, a surgeon often cuts away the damaged area because larger regions may not heal completely, leaving frayed edges that can make it hard and painful to bend the knee. But the surgery leads to problems. In the December issue of Arthritis Care & Research, doctors reported that 45 patients, ages 38 to 50, had weakness in their thigh muscles and unstable knees as long as six years after their surgery. The doctors say that continued pain—because the shock absorber has been reduced—often causes patients to keep weight off the hurt leg, reducing muscle strength. That just makes matters worse. And even though such people are told to exercise at home, it's generally unsupervised, rather than a rigorous program of physical therapy that might produce better results.
"I think surgery happens far too frequently, and it doesn't necessarily help with these injuries," says David Hunter, a rheumatologist at Boston University's School of Medicine. "The meniscus performs a vital function, and if it can be preserved, it's best left that way."
Hunter headed up a study of 257 patients with meniscus damage that he reported in the March issue of Arthritis & Rheumatism. Though only 27 percent of these people had had knee surgery, all showed shrinkage or deterioration of these pads in a way that mimicked partial surgical removal. And those who lost the largest amount of meniscus, Hunter found, had a risk of cartilage damage that was three times higher than people who lost the least. Losing these shock absorbers means that cartilage rubs and wears away, leading to painful osteoarthritis.
It's far better to treat meniscus problems with exercise, physical therapy, knee braces, and weight reduction, Hunter says.
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