Hip Anatomy and Function
How a Healthy Hip Works
The hip is one of the main weight-bearing joints in your body. It consists of two main parts:
- A ball (femoral head)at the top of your thighbone (femur)
- A rounded socket (acetabulum)in your pelvis
Ligaments, which are bands of tissue, connect the ball to the socket and help keep the ball and socket steady. A smooth, tough material called articular cartilage, which cushions the bones and lets them move easily, covers the surfaces of the ball and socket.
All the rest of the surfaces of the hip joint are covered by a thin, smooth tissue liner called synovial membrane, which makes a small amount of fluid that acts as a lubricant so that the bones in the hip joint will not rub against each other.
What causes hip pain?
Pain in your hip can be debilitating, making it difficult for you to walk, climb stairs, or even pick up an object from the floor. It can limit your freedom of movement and ability to function independently.
While hip pain can be caused by deformity or by direct injury, like trauma or a sports injury, the most common cause of hip pain is osteoarthritis (OA) also known as degenerative joint disease (DJD). Depending on factors like age, weight, joint function, and activity, people with arthritis find their hip’s cartilage lining wears away over time. At that point, your bones begin to rub against each other, resulting in friction, swelling, pain, stiffness, and instability.
Experiencing joint pain day after day without relief can lead to “staying off” the joint — which often weakens the muscles around it so it becomes even more difficult to move.
Your Treatment Options for Hip Pain
You don’t have to live with severe joint pain and the functional limitations it causes. If you have not experienced adequate results with medication and other conservative treatments, total joint replacement may provide the pain relief you long for, in addition to allowing you to return to the lifestyle and activities you enjoy. Your orthopaedic specialist can tell you whether you might benefit from joint replacement and explain the reasons why it may, or may not, be right for you.
Of course, even if your orthopaedic specialist determines that joint replacement is a good medical option for you, it is still up to you to make the final decision. The ultimate goal is for you to be as comfortable as possible, and that always means making the best decision for you based on your own individual needs.
About Total Hip Replacement
Hip replacement surgery involves replacing the femur (head of the thighbone) and the acetabulum (hip socket). Typically, the artificial ball with its stem is made of a strong metal or ceramic, and the artificial socket is made of polyethylene (a durable, wear-resistant plastic) or metal backed with a plastic liner. The artificial joint may be cemented in position or held securely in the bone without cement.
Total Hip Joint Replacement
You Don’t Have to Live with Joint Pain
Your joints are involved in almost every activity you do. Simple movements such as walking, bending, and turning require the use of your hip and knee joints. Normally, all parts of these joints work together and the joint moves easily without pain. But when the joint becomes diseased or injured, the resulting pain can severely limit your ability to move and work. Osteoarthritis, one of the most common forms of degenerative joint disease, affects an estimated 43 million people in the United States.1 Whether you are considering a total joint replacement, or are just beginning to explore available treatments, this website is for you. It will help you understand the causes of joint pain and treatment options. Most importantly, it will give you hope that you may be able to return to your favorite activities.
Once you’re through reading this website, be sure to ask your doctor any questions you may have. Gaining as much knowledge as possible will help you choose the best course of treatment to relieve your joint pain — and get you back into the swing of things.
- Arthritis Foundation website, Feb. 2006.
What is a Hip Joint?
Your hip joint is a ball-and-socket joint, formed by the ball, or femoral head, at the upper end of the thighbone, and the rounded socket, or acetabulum, in the pelvis. The bone ends of a joint are covered with a smooth, tough material called cartilage. Normal cartilage cushions the bones and allows nearly frictionless and pain-free movement. The rest of the surfaces of the joint are covered by a thin, smooth tissue lining called the synovium. The synovium produces fluid that acts as a lubricant to reduce friction and wear in the joint.
Common Causes of Joint Pain
Sometimes called degenerative arthritis because it is a “wearing out” condition involving the breakdown of cartilage and bones. When cartilage wears away, the bones rub against each other, causing pain and stiffness. OA usually occurs in people aged 50 years and older, and frequently in individuals with a family history of arthritis.
Rheumatoid Arthritis (RA)
Causes the synovium to become thickened and inflamed. In turn, too much synovial fluid is produced within the joint space, which causes a chronic inflammation that damages the cartilage. This results in cartilage loss, pain, and stiffness. RA affects women about 3 times more often than men, and may affect other organs of the body.
May develop after an injury to the joint in which the bone and cartilage do not heal properly. The joint is no longer smooth and these irregularities lead to more wear on the joint.
Can result when bone is deprived of its normal blood supply. Without proper nutrition from the blood, the bone’s structure weakens and may collapse and damage the cartilage.
A bone disease that often affects the hip. Bone formation is sped up, causing the density and shape of the bone to change. Joint pain can also be caused by deformity or direct injury to the joint. In some cases, joint pain is made worse by the fact that a person will avoid using a painful joint, weakening the muscles and making the joint even more difficult to move.
Following the orthopaedic evaluation, your orthopaedic surgeon will review and discuss the results with you. Based on his or her diagnosis, your treatment options may include:
- Joint fluid supplements
- Physical therapy
- Joint replacement
- Orthopedics.about.com website, Feb. 2006.