Damage to the cartilage pads (menisci) in the knee joints
Damage to cartilage commonly occurs in the knee joint, where two cartilage discs, known as menisci, act as shock absorbers between the femur (thighbone) and tibia (shinbone). These discs help to distribute body weight in the joint. A torn cartilage often occurs in football players and is therefore more common in men. The injury is usually caused by a sudden twisting of the leg, often with the knee bent and the foot on the ground. A cartilage can tear without sudden injury, and people whose occupation involves squatting down and placing strain on the knees are at risk.
If you do tear a cartilage abruptly, you will feel a sharp pain and may hear a noise at the time of the injury. Pain usually becomes worse on moving the joint, and swelling may develop immediately or several hours later. You will probably be unable to straighten the joint. A torn cartilage may prevent the leg from supporting your body weight.
Your doctor will examine your knee and probably arrange for an X-ray to check for bone damage. The diagnosis may be confirmed by examining the knee using MRI or arthroscopy. Sometimes, damaged knee cartilage is repaired surgically under a general anaesthetic, and most people are able to use the injured joint 2–3 weeks afterwards. Physiotherapy may be needed to help to mobilize the affected joint. There is a risk that torn knee cartilage may lead to early development of osteoarthritis, a degenerative disorder of the joints.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.