The meniscus is a C-shaped cartilage that sits between the femur and tibia. You have one on the inside of the knee (medial meniscus) and on on the outside (lateral meniscus). These act as a shock absorber in the knee. They also act as stabilisers of the knee in conjunction with the cruciate and collateral ligaments, during flexion and extension. They help to cushion and to protect the joint surfaces from overload, wear and ultimately arthritis.
They do not have a very good blood supply and damage to the meniscus therefore does not heal particularly well by itself. However you may find that symptoms of a meniscal tear improve, even if the tear itself does not heal.
The meniscus can be torn through injury, and this torn meniscus can give rise to pain or other problems within the knee. Meniscal tears are divided into two categories:
Traumatic – these are tears that are usually caused by a particular trauma such as a twisting injury. They are often associated with sport, and many footballers have injured their meniscus.
Degenerate – as you develop arthritis, and the joint surfaces become less smooth, you are more likely to catch the meniscus within the joint and this repetitive micro-trauma may eventually lead to a “degenerate” tear.
What symptoms do meniscal tears cause?
A torn meniscus can be painful, but it often also gives you what are termed “mechanical symptoms” – the knee locks so that it won’t go completely straight or gives way, often with minimal warning. The pain from the torn meniscus is usually felt along the line of the joint, you may well notice swelling, particularly after exercise.
What treatments are available?
Many degenerate tears will improve with time, painkillers and physiotherapy. If you have tried these treatments and you still have symptoms, then surgery may be required.
A “locked knee” (i.e. one that will not fully straighten) – due to a piece of meniscus jamming the joint – requires surgery, and is better performed sooner rather than later. This is to avoid the knee becoming stiff in its bent position, which will increase the recovery period following surgery.
Meniscal surgery is performed as part of a knee arthroscopy, and is a day-case operation. Depending on the size and site of the tear, the damaged part of the meniscus may be repaired or removed. Further information on these operations can be found on this site under the Knee Arthroscopy menu.