What is Hip Replacement

If your hip has been damaged by arthritis, a fracture or other conditions, common activities such as walking or getting in and out of a chair may be painful and difficult. You may even feel uncomfortable while resting.

If medications, changes in your everyday activities, and the use of walking aids such as a cane are not helpful, you may want to consider hip replacement surgery. By replacing your diseased hip joint with an artificial joint, hip replacement surgery can relieve your pain and help you get back to enjoying normal, everyday activities.

How the Normal Hip Works

The hip is one of your body's largest weight-bearing joints. It consists of two main parts: a ball (femoral head) at the top of your thighbone (femur) that fits into a rounded socket (acetabulum) in your pelvis. Bands of tissue called ligaments connect the ball to the socket and provide stability to the joint.

The bone surfaces of your ball and socket have a smooth durable cover of articular cartilage that cushions the ends of the bones and enables them to move easily.

All remaining surfaces of the hip joint are covered by a thin, smooth tissue called synovial membrane. In a healthy hip, this membrane makes a small amount of fluid that lubricates and almost eliminates friction in your hip joint.

Normally, all of these parts of your hip work in harmony, allowing you to move easily and without pain.

Common causes of hip pain and loss of hip function

The most common cause of chronic knee pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis, and traumatic arthritis are the most common forms.

Osteoarthritis usually occurs after the age of 50 and often in an individual with a family history of arthritis. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another causing knee pain and stiffness.

Rheumatoid Arthritis is a disease in which the synovial membrane becomes thickened and inflamed, producing too much synovial fluid which over-fills the joint space. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain and stiffness.

Osteonecrosis is a disease resulting from the temporary or permanent loss of the blood supply to the bones.

Traumatic Arthritis can follow a serious knee injury. A knee fracture or severe tears of the knee's ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.

How the replaced hip works

The diseased cartilage and irritated nerve endings have been replaced by highly durable materials, both at the femur and at the tibia (knee cap not shown). Full, free painless range of motion has been restored. (Oblique view of a left knee replacement, view image).

Realistic Expectations About Hip Replacement

An important factor in deciding whether to have a hip replacement is understanding what the procedure can and can't do.

The vast majority of individuals who undergo hip replacement surgery experience a dramatic reduction of hip pain and a significant improvement in their ability to perform the common activities of daily living. However, hip replacement surgery will not enable you to do more than you could before your hip problem developed.

Following surgery, you will be advised to avoid certain activities for the rest of your life including jogging and high-impact sports.

Even with normal use and activities, an artificial joint (prosthesis) develops some wear over time. If you participate in high-impact activities or are over-weight, this wear may accelerate and cause the prosthesis to loosen and become painful.

About the Surgery

The surgical procedure takes a few hours. Your orthopaedic surgeon will remove the damaged cartilage and bone, then position new metal and plastic joint surfaces to restore the alignment and function of your hip.

Many different types of designs and materials are currently used in artificial hip joints. All of them consist of two basic components: the ball component (made of a highly polished strong metal) and the socket component (a durable plastic cup which may have an outer metal shell).

A special surgical cement may be used to fill the gap between the prosthesis and remaining natural bone to secure the artificial joint.

A noncemented prosthesis has also been developed which is used most often in younger, more active patients. The prosthesis may be coated with textured metal or a special bone-like substance which allows bone to grow into the prosthesis. A combination of a cemented ball and a noncemented socket may be used. Your orthopaedic surgeon will choose the type of prothesis that best meets your needs.

How Is Your New Hip Different

You may feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending. These differences often diminish with time and most patients find these are minor compared to the pain and limited function they experienced prior to surgery.

Your new hip may activate metal detectors required for security in airports and some buildings. Tell the security agent about your hip replacement if the alarm is activated. You may ask your orthopaedic surgeon for a card confirming that you have an artificial hip.

After surgery, make sure you also do the following:

Participate in a regular light exercise program to maintain proper strength and mobility of your new hip. Take special precautions to avoid falls and injuries. Individuals who have undergone hip replacement surgery and suffer a fracture may require more surgery. Notify your dentist that you have had a hip replacement. You should be given antibiotics before all dental surgery for the rest of your life. See your orthopaedic surgeon periodically for routine follow-up examinations and X-rays.

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