allograft

A bone graft transplants bone tissue. Surgeons use bone grafts to repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Grafts can also repair bone loss caused by some types of fractures (broken bones) or cancers. Once your body accepts the bone graft, it provides a framework for growth of new, living bone.

If the transplanted bone comes from another person, it is called an allograft. Most allograft bone comes from donors who have died. Tissue banks screen these donors and disinfect and test the donated bone to make sure it is safe to use. If the transplanted bone comes from another part of your own body, it is called an autograft. Autograft bone often comes from your ribs, hips or a leg.

Cartilage is the tough but flexible tissue that covers the ends of your bones at a joint. It also gives shape and support to other parts of your body, such as your ears, nose and windpipe. Healthy cartilage helps you move by allowing your bones to glide over each other. It also protects bones by preventing them from rubbing against each other.

Injured, inflamed, or damaged cartilage can cause symptoms such as pain and limited movement. It can also lead to joint damage and deformity. Causes of cartilage problems include :

• Tears and injuries, such as sports injuries
• Genetic factors
• Other disorders, such as some types of arthritis

Osteoarthritis results from breakdown of cartilage.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.

Knee problems are very common, and they occur in people of all ages. Knee problems can interfere with many things, from participation in sports to simply getting up from a chair and walking. This can have a big impact on your life.

The most common disease affecting the knee is osteoarthritis. The cartilage in the knee gradually wears away, causing pain and swelling.

Injuries to ligaments and tendons also cause knee problems. A common injury is to the anterior cruciate ligament (ACL). You usually injure your ACL by a sudden twisting motion. ACL and other knee injuries are common sports injuries.

Treatment of knee problems depends on the cause. In some cases your doctor may recommend knee replacement.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases