Can You Use a Treadmill With a Torn Miniscus?

The knee is the largest joint in the body. Composed of three bones -- the femur, or thigh bone, the tibia, or shin, and the kneecap -- the knee is stabilized by four ligaments and cushioned by the menisci, two rubbery, disc-shaped pieces of cartilage that prevent friction between the bones. Any sudden twisting movement of the knee, whether during athletic activity or an accidental slip and fall, can injure one or more of these structures.

A torn meniscus is the most common knee injury. About 850,000 surgeries to repair meniscus tears are performed in the United States annually. In younger people, a torn meniscus is usually sports-related and is frequently accompanied by an injury to a ligament. A tear can occur anywhere on the surface of the cartilage on either the inner or outer part of the knee.

Initially, symptoms are absent or very mild. Over the course of several days, however, the knee becomes painful, stiff and mildly swollen. You may hear a clicking sound or feel the knee catch when you move it in certain ways. The damaged meniscus can also become wedged inside the knee joint, immobilizing the joint. At other times, a tear may cause weakness and a feeling that the knee is about to give out.

Previously, doctors recommended surgery for a torn meniscus, believing that the meniscal cartilage was incapable of healing itself owing to its poor blood supply. At least two research studies seem to suggest otherwise,however. The first, published online in the "New England Journal of Medicine" on March 18, 2013, was a randomized study of 351 adults over the age of 45 with both arthritis and meniscal tears. Participants received either arthroscopic surgery or nine sessions of physical therapy followed by a regimen of exercises to perform at home. After six months, both groups had the same level of functional improvement and the same pain scores.

In a second study, Finnish researchers performed either arthroscopic surgery or "sham" surgery on 146 subjects with meniscal tears who did not have arthritis. Both groups received postoperative physical therapy and had almost identical levels of improvement a year later, reports the "New York Times."

Like any traumatic injury, a torn meniscus causes inflammation, which can negatively affect your ability to heal. In a 2008 study published in the Arthritis Foundation Research Update, scientists applied interleukin-1, an inflammatory molecule, to torn meniscal tissue from mature pigs to determine how inflammation impacted meniscal healing. Even one day of exposure to the inflammatory molecule reduced strength and decreased new cell production and tissue repair.

These results strongly suggest that performing strenuous exercise after a meniscal tear may cause delayed healing and complications later on. Your doctor will have the best advice about exercising with a torn meniscus and can provide guidance about the fitness activities that are appropriate if you've been diagnosed with this injury.

Your rehabilitation after a meniscus injury depends largely on the extent and location of the tear and the treatment that you and your doctor choose. If you decide to forgo surgery, your doctor likely will recommend a structured program of physical therapy for four to six weeks. Initially these exercises will focus on strengthening the quadriceps, improving range of motion in the knee and promoting flexibility in the ligaments. Then, light weight-bearing and low-impact aerobic activities, such as walking on a treadmill or around a track may begin.

If you have surgery, your doctor will instruct you when to resume normal activities based on how you recover. Important benchmarks are the recovery of normal strength in your leg and being able to bend and straighten your knee and perform a squat or a deep knee bend without pain.