Two studies raise questions about knee surgery

Knee injuries aren’t always as dramatic as New England Patriots quarterback Tom Brady’s sudden, season-ending tears of two ligaments on Sunday.

Sometimes people don’t even know they have damage to parts of the knee called the menisci, two crescent-shaped disks of cartilage that cushion the thigh and shin bones in the knee joint. A survey of middle-age and older Framingham residents led by Boston University School of Medicine researchers found not only that meniscal tears are common in this age group, but that most of the people who had them didn’t feel any pain or stiffness in the affected knee.

If meniscal tears are more common than previously thought, that could make a difference in how doctors and patients decide how to treat knee problems, the authors write in the New England Journal of Medicine. Osteoarthritis, not the meniscal tear, may be the reason why a person feels pain, for example, making surgery to repair the meniscus less likely to solve the problem.

“Clinicians who order MRI of the knee should take into account the high prevalence of incidental tears when interpreting the results and planning therapy,” the authors write.

Another article in this week's Journal also sounds a note of caution about knee surgery. Canadian researchers report that arthroscopic surgery for osteoarthritis of the knee was no better than physical therapy or medication.

The BU study subjects weren’t the people made famous by the long-running Framingham Heart Study and its offspring cohort. The 991 people in this study were 50 to 90 years old. Randomly contacted by telephone, they were asked questions about knee symptoms, examined by doctors, and given an MRI scan from 2002 to 2005. Anyone who had had knee surgery, rheumatoid arthritis, or serious illnesses was excluded.

Meniscal damage in the right knee was common and the prevalence increased with age, the researchers said. (Only the right knee was included because of funding limitations, the authors say.) Almost one in five women who were 50 to 59 years old had meniscal damage, but more than half of men 70 to 90 years old had the same kind of damage. Almost two-thirds of people whose imaging tests showed they had osteoarthritis also had meniscal tears. Less than a third of people without osteoarthritis had meniscal tears.