The meniscus is a cartilage structure inside the knee joint which serves as a shock absorber. Each knee has a medial and a lateral meniscus, either of which can be torn. Meniscal injuries in athletes typically occur by a twisting or pivoting type of mechanism, and often occur in conjunction with an ACL tear. Degenerative type meniscal tears are also very common, occurring in arthritic knees. Treatment for a torn meniscus can range from non-operative, to partial removal of the meniscus or partial menisectomy, to meniscal repair.
The decision to proceed with repair vs. partial removal is made at the time of arthroscopic surgery and is based on a combination of factors. These include the type of tear (simple vs. complex), location of the tear, size of the tear, patient age, and chronicity of the tear. The location of the tear predicts the blood supply to the torn meniscus which is a large determinate of healing potential. Partial removal is often necessary and does result in a much quicker recovery and return to sports. The removed meniscus however will not grow back and meniscus removal is associated with future arthritic changes to the knee. The more meniscus is removed, the greater chance for significant arthritic changes.
Every attempt is made to repair the meniscus in younger patients with significant tears and certainly in adolescent patients. In my opinion, the benefits of keeping the meniscus outweigh the risk of having to return to surgery for a repair which does not heal in this age group. Younger patients typically have more healing potential, will place more demand on the knee, and have a greater time period for arthritic symptoms to develop. Meniscus repair requires more significant post-operative restrictions, such as limited weight bearing with crutches and typically 3-4 months before returning to sports.
Degenerative, complex, and chronic tears have far less potential for healing and are almost always treated with partial removal of the meniscus. Partial menisectomy involves removing any torn or unstable pieces of meniscus while preserving as much remaining normal and/or stable meniscus as possible. The risk of returning to surgery in this situation now outweighs the benefits of attempted meniscus repair. Recovery typically takes around one month following this procedure but does vary from patient to patient. The condition of the adjacent articular cartilage or cartilage covering the bone including arthritic changes is predictive of the overall success with this procedure. Those with more significant arthritic changes will typically have more residual symptoms.
Non-operative treatment also plays a significant role in the treatment of degenerative type meniscal tears. This may include exercise, physical therapy, medications, cortisone injections, weight loss, and observation. Many tears are identified with MRI but are not causing any symptoms and do not require surgical treatment. Symptomatic treatment with the above options without surgery can often result in resolution of pain.