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.

Arthritis is the most common disease that affects bones in your knees. 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.

Hip Pain/Injuries

Your hip is the joint where your thigh bone meets your pelvis bone. Hips are called ball-and-socket joints because the ball-like top of your thigh bone moves within a cup-like space in your pelvis. Your hips are very stable. When they are healthy, it takes great force to hurt them.

Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited motion. Osteoporosis of the hip causes weak bones that break easily. Both of these are common in older people. However, playing sports, running, overuse or falling can all sometimes lead to hip injuries. These may include:

• Sprains and strains
• Bursitis
• Dislocations
• Fractures