Menisci are two crescent-shaped (half moon) discs between the thigh bone (femur) and the leg bone (tibia). They serve as shock absorbers and have several other important functions too.
Meniscal lesions are commonly seen above the age of 40 and menisci can tear without significant injury In rare instances when there is a developmental error (manufacturing defect !), the meniscus may be shaped like a disc instead of a half moon and it is then called a discoid meniscus. Such menisci are more prone to tear and may present as a painful or clicking or intermittently locked knee in children. Complex meniscal injuries are associated with cruciate or multiligament injuries and are addressed during the ligament reconstruction procedure.
A meniscus tear usually presents with pain in the inner or outer aspect of knee. In some cases patients presents with locking of the knee.
Only meniscal tears that cause pain, limp, restricted movements or locking (unable to straighten the knee) require surgery. Occasionally, meniscal tears are associated with a cyst (commoner on the outer or lateral side). Meniscal surgery is generally a planned procedure however, in case of a "locked knee", early surgery is advised to prevent joint damage.
Meniscus tears seen on MRI but not causing any symptoms are best left alone and do not need any intervention.
Meniscal tears that cause symptoms of pain, limp, localised painful swelling or locking, benefit from arthroscopic surgery which is of two types -
A. Meniscectomy - the damaged portion of the meniscus is trimmed and the healthy portion preserved
B. Meniscal repair - where the torn meniscus is stitched back using specialised techniques / implants.
Meniscal tears rarely heal on their own because of poor blood supply and with time, the tear often increases in size. Early intervention for symptomatic meniscal tears is therefore advisable