Basically, the knee is two long leg bones held together by muscles, ligaments, and tendons. Tendons are tough cords of tissue that connect muscles to bones. Ligaments are elastic bands of tissue that connect bone to bone. Other knee problems are a result of an injury or a sudden movement that strains the knee. Symptoms often include pain, swelling, and difficulty in walking.
Cartilage tears can often occur with sprains.
Treatment may involve wearing a brace during an activity to protect the knee form further injury. Surgery may be needed to repair the tear. Tendonitis of the patellar tendon is called jumper's knee. This often occurs with sports such as basketball, where the force of hitting the ground after a jump strains the tendon. Osteoarthritis is a degenerative process where the cartilage in the joint gradually wears away, and often affects middle-age and older people.