Knee repair surgery doesn't need to be avoided in heavier patients

Nearly 1 in 6 patients who receive an important knee surgery will end up right back in the operating room because the first repair failed. For years, doctors presumed a person’s weight was a leading factor of failure, but a new study from Ohio State shows there is no such connection.

Repair of the meniscus knee ligament is one of the most common orthopedic surgeries in the U.S. (The meniscus provides crucial padding at the knee joint between the femur and tibia bones in the leg.)

David Flanigan, MD, lead author of the study and orthopedic surgeon at The Ohio State University Wexner Medical Center, says many logically assumed an increased body mass index (BMI) is a good predictor of whether this knee surgery will fail. 

BMI is a measure of body fat based on your weight in relation to your height. A BMI of more than 25 is considered overweight and a measure of over 30 is rated as obese.

“Our thought was that increased load would be detrimental to a repair and likely cause increased failure rates in heavier patients,” he  says. “What we found, though, was that wasn’t true.”

The results of the study mean surgeons should not consider weight as a factor when deciding if a patient is a good candidate for meniscal repair surgery, according to Dr. Flanigan.

“If a meniscus is repairable, and surgery is appropriate for that patient, you can do the surgery and they would have the same success as someone who is not as heavy,” he says.

Meniscus tears typically occur in younger patients, often as the result of a sporting accident. Later in life is another common time for people to experience tears of the ligament.

“The meniscus ages just like we age and becomes a little bit weaker. It’s much more easy to tear as we get older,” he says.

Steven Doukides was walking home from a concert when a short hop over a pothole ended with him tearing several ligaments in his knee. He met with Dr. Flanigan about his knee repair options.

Doukides was glad to know his knee would not only be repaired correctly, but the end result would be just as reliable as others.

“You don’t realize how important it is getting around until you are immobilized, until you can’t get around,” Doukides says. “It’s an eye-opening experience.”

The study, published in The Journal of Knee Surgery, followed more than 400 patients who underwent meniscal repair surgery from 2006 to 2012. The results showed no significant difference in the rate of failures in those with a normal BMI (less than 25) and those with an elevated BMI (25 or higher).

Surgeons often use risk factors such as weight, activity level, type of meniscus tear and stability of the knee to determine which type of surgery to perform on a patient with a torn meniscus. If there is a good chance of the repair failing, the surgeon may opt to do a meniscectomy – a removal of part, or all, of the meniscus. This often leaves the patient with a less stable knee that is unable to withstand much activity.

Additional research shows repairing the meniscus whenever possible, as opposed to removing it, actually prevents knee issues in the future.

“That structure is so vital to the knee and provides a cushion to the joint,” Dr. Flanigan says. “Repairing it can prevent some of the arthritic changes from progressing in the knee. So if a meniscus is repairable, I’m very aggressive to perform that procedure.”

Dr. Flanigan points out, because of the study’s pool of participants, it remains unclear if those with extremely high BMI will have the same rate of success as others, regardless of their BMI.  

“When I’m looking at a patient, I really don’t consider their BMI, if they have a repairable meniscus.”