The most common injuries to the knee are the result of wrenching and twisting forces or a traumatic blow to the joint and most often involve only the soft tissues of the knee -- the ligaments, tendons, muscles, and the cartilage or menisci. The types of injuries that may result include a sprain, in which the tissues are "pulled" beyond their normal elastic limits, or a tear or rupture, usually caused by a twisting force while the knee is bearing weight. There may be a partial or complete tear of the structure and in some cases, an accompanying fracture or splintering of bone tissue at the site of bone and soft-tissue connection.

Sprained ligaments are among the most common injuries associated with sports. The signs and symptoms of a sprained or torn ligament include a sensation of a "pop" within the joint upon impact, a lack of stability when you try to stand on the affected leg, pain, swelling, and reduced mobility of the joint. Similar symptoms are experienced when there is a tear or rupture of a tendon or cartilage, and the joint may produce a "clicking" sound during movement. In some cases, the knee "locks," and mobility of the joint is reduced.

Minor injuries to the soft tissues of the knee may respond well to first aid (the RICE formula). If symptoms persist for more than one or two weeks, a physician should be consulted.

Overuse

The term "overuse" injury refers to the effects of repeated, minor trauma to the knee joint. This trauma may result from recreational or competitive running, or  jumping as a sport or as part of a sport, such as in basketball. The injury occurs gradually, and symptoms may not interfere with the performance of the activity at first. When symptoms do appear, they are usually noticed within 24 hours of performing the activity that is producing trauma to the knee. These symptoms may include a dull ache, a specific type of discomfort when the joint is moved a certain way, such as a burning sensation or shooting pain, and sometimes pain when the affected area is touched or pressure is applied to the leg. Pain may be accompanied by swelling.

Resting the knee and using first aid measures, such as elevation and ice therapy, may bring relief. However, you should consult an orthopedic specialist if you cannot change your activities to rest the knee or if symptoms persist. In some cases, your activities can be modified to lessen the trauma on the affected knee, or special equipment may be used to provide additional support to the joint. The orthopedic specialist can help prevent a recurrent injury by prescribing exercises to improve the strength and mobility of the affected knee and its supporting structures.

Abnormalities may include Iliotibial Band Syndrome, Plica Syndrome, Osgood-Schlatter Disease.
 

Degenerative Joint Diseases

Degenerative diseases of the knee most often involve the cartilage that protects the knee joint. Conditions may include chondromalacia, Osteochondritis Dissecans and Arthritis