The hip joint is a ball-and-socket joint formed by the head of the femur, or thigh bone, and the acetabulum of the pelvis. This union supports weight bearing as well as absorbing the forces created by physical activity, standing, and sitting. 

Strong capsular ligaments surround and support the hip joint, and muscles from the lower back, pelvis and thigh contribute to strength and stability. The head of the femur is covered with a smooth layer of cartilage, which helps to absorb shock and reduce friction during movement, while synovial fluid further cushions the joint and transports essential nutrients to joint structures. 

Important differences exist in the size and structure of the hip and pelvis in men and women. A woman's bone structure is slightly less dense than a man's, and the pelvis is smaller, shorter and wider. Additionally, the bony protrusions for muscle attachment are not as sharply defined. 

Common Problems of the Hip
 

Muscle Strain Bursitis

Arthritis Fracture

Muscle Strain
One of the most common problems of the hip is a muscle strain or tear. This frequently occurs when an athlete tries to change directions, or start and stop suddenly. Frequently there is a sudden onset of pain and swelling. Walking may be difficult and running is nearly impossible. 

The initial treatment of a muscle strain or tear is rest, letting the pain be the guide to activities. Ice is used for 48 hours followed by heat, stretching exercises, and then ice. Ice massages seem to be particularly helpful. Stretching exercises should be initiated as soon as the initial tenderness diminishes, usually within 24-48 hours. Nonsteroidal anti-inflammatory medicines help reduce the pain, tenderness, and swelling. The torn muscle tends to heal with scar tissue so it is important that the stretching exercises are done daily to preserve the length of the muscle and to prevent the scar tissue from contracting.

Bursitis
The most frequent location for bursitis is over the outside of the hip. This is called greater trochanteric bursitis. Tenderness over the outside of the hip, one of the symptoms of bursitis, can frequently be made worse by walking, running, or twisting the hip in certain directions. 

The initial treatment for bursitis is heat to the affected area, followed by stretching exercises and ice massage. Nonsteroidal anti-inflammatory medicines are also quite helpful. Should symptoms continue, sometimes a local steroid injection is very helpful in resolving hip bursitis.

Arthritis
Arthritis is a very common hip problem, particularly in older people or in people who have had a prior hip injury. Symptoms of arthritis of the hip include pain in the hip area which may radiate into the groin and into the thigh. Frequently this pain is worse when getting up from a sitting position or when walking. The hip may also catch, pop or give way. Once the arthritis is present, it tends to gradually get worse, although the course of arthritis is quite variable. 

The treatment for arthritis is moderate exercise to strengthen the muscles around the joint, particularly non-impact exercises such as swimming or water aerobics. Heat or ice also frequently help with the symptoms, particularly towards the end of the day. Nonsteroidal anti-inflammatory medicines will help to relieve a great deal of discomfort. Ultimately, a total hip replacement surgery may be required. While this is a major surgery, it is usually quite effective in relieving the pain associated with hip arthritis.

Fracture
Many people, particularly the elderly,  suffer hip fractures from falling. Most of these fractures are near the hip joint and are called either femoral neck fractures or intertrochanteric hip fractures. 

Both of these fractures require surgical treatment in order to preserve independence and freedom of movement, with the least chance of potential problems. A hip fracture can be an especially severe injury, particularly in an elderly person.