Hip joint replacements

Total hip replacement involves implanting two major components into the hip joint. A plastic socket (the acetabular component) is implanted into the pelvis to replace the damaged socket. This is made of ultra-high molecular weight polyethylene that is extremely durable and wear resistant.

The natural head of the femur (the long leg bone) is removed and replaced by a ball and stem (femural component) which fits down inside the bone. These artificial components (prosthesis) are generally made of metal or ceramic ball.

The metals are varied and include stainless steel, or alloys of cobalt, chrome and titanium. Zan acrylic bone cement is often used to anchor the artificial joint into the bone. Sometimes cement is not used, but both types of replacement are very successful.

How long will the new joint last?

For most older people, the hip replacement is likely to last for the rest of your life unless there is some loosening or other problem - 15 to 20 years is quite common. A younger person may require a second joint replacement later in life.

How long will recovery take?

The recovery period following surgery will vary depending on the patient. In general, the orthopaedic surgeon will encourage you to use the joint soon after the operation. You will be back on your feet and beginning to walk within several days, although you are likely to be using crutches or a cane for a period of time. You will also learn to do appropriate exercises to move and strengthen the joint.

It takes about three months for the muscle and tissue around the hip to heal. During this time there is a danger that your new hip could dislocate (the ball part coming out of the socket), so there are some important points and precautions you can take to avoid this happening.

Precautions after hip replacement surgery

• Do not bend your hip so that the angle between your body and your operated leg is less than 90 degrees. Avoid sitting on low chairs for this reason.
• Do not cross your legs at all (this includes ankles and knees) and do not let your operated leg cross the middle of your body.
• Do not twist your operated leg inwards or outwards. When walking and turning, keep your toes pointed ahead.
• Avoid all forceful or jarring movements of your hip.
• Do not lie on your operated side in bed. Always have a pillow between your legs if you are lying on your unoperated side.
• Before dental work or surgery, let your dentist know you have a prosthesis; antibiotics may be needed to prevent infection.
• Call your doctor or surgeon if you have increased hip pain, swelling, incision draining, chest pain, shortness of breath or any other symptoms you do not understand.

See also: Risks and benefits of joint surgery

Original material provided by Arthritis New Zealand. Edited by everybody, July 2005.