The hip joint is a ball-in-socket joint where the ball or head of the femur (thigh bone) joins the pelvis at the socket called the acetabulum.
Hip Joint replacement or Total Hip Replacement is surgery to replace all or part of the hip joint with an artificial device to restore joint movement (a prosthesis). Hip joint replacement is mostly done in older people. The operation is usually not recommended for younger people because of the strain they can put on the artificial hip.
The indications for the replacement of the hip joint include:
- hip pain that has failed to respond to conservative therapy (NSAID medication for 6 months or more)
- hip osteoarthritis or arthritis confirmed by X-ray
- inability to work, sleep, or move because of hip pain
- loose hip prosthesis
- some hip fractures
- hip joint tumors
This surgery is not recommended for:
- current hip infection
- poor skin coverage around hip
- paralysis of the quadriceps muscles
- severe disease of the blood vessels of the leg and foot (peripheral vascular disease)
- nerve disease (neuropathy) affecting the hip
- severe limiting mental dysfunction
- serious physical disease (terminal disease, such as metastatic disease)
- morbid obesity (over 300 lb.)
The hip is made of a ball and a socket joint, linking the dome at the head of the thigh bone (femur) and the cup in the pelvic bone. A total hip prosthesis is surgically implanted to replace the damaged bone within the hip joint.
The total hip prosthesis consists of three parts:
- a plastic cup that replaces your hip socket (acetabulum)
- a metal ball that will replace the fractured femoral head
- a metal stem that is attached to the shaft of the bone to add stability to the prosthesis
If a hemi-arthroplasty is performed, either the femoral head or the hip socket (acetabulum) will be replaced with a prosthetic device. You will receive an extensive pre-operative evaluation of your hip to determine if you are a candidate for a hip replacement procedure. Evaluation will include assessment of the degree of disability and impact on your lifestyle, pre-existing medical conditions, and an evaluation of heart and lung function.
The surgery will be performed using general or spinal anesthesia. The orthopedic surgeon makes an incision along the affected hip joint, exposing the hip joint. The head of the femur and the cup are cut out and removed.
Then a metal ball and the metal stem is inserted in the femur and a plastic socket is placed in the enlarged pelvis cup. The artificial components are fixed in place (sometimes a special cement is used). The muscles and tendons are then replaced against the bones and the incision is closed.
You will return from surgery with a large dressing to the hip area. A small drainage tube will be placed during surgery to help drain excess fluids from the joint area.
You will experience moderate to severe pain after surgery. However, patient-controlled analgesia (PCA), intravenous (IV), or epidural analgesics are effective in controlling post-operative pain. The pain should gradually decrease, and by the third day after surgery, oral analgesic medications may be sufficient to control your pain. Try to schedule your pain medications about one half hour before ambulation or position changes.
Results with a hip prosthesis have been excellent. The operation relieves pain and stiffness symptoms, and most patients (over 80%) need no help walking. With time, loosening of the artificial joint has been observed due to the limited properties of the cement used to attach the artificial parts to the bones.
You will remain in the hospital for 5 to 8 days after surgery. However, some people may need further rehabilitation and assistance after hip replacement surgery. Temporary placement in a rehabilitation unit or long-tern care center may be necessary until mobility has improved and the person can safely live independently. These centers will provide intensive physical therapy to assist in regaining muscle strength and flexibility in the joint.
Positioning is very important after surgery to reduce stress on the new joint and displacement of the joint. The new hip will not have the same range of movement of the original joint, although you should eventually be able to return to your previous level of activity. However, you should avoid vigorous sports such tennis, skiing, or contact sports.
The use of crutches or a walker is necessary for 3 months or more until healing is complete.
The new joint has a limited range of movement. You will need to take special precautions to avoid displacement of the joint, including:
- Avoid crossing your legs or ankles even when sitting, standing, or lying.
- When sitting, keep you feet about 6 inches apart.
- When sitting, keep your knees below the level of your hips. Avoid chairs that are too low. You may sit on a pillow to keep your hips higher that your knees.
- When getting up from a chair, slide toward the edge of the chair and then use your walker or crutches for support.
- Avoid bending over at the waist. You may consider purchasing a long-handled shoehorn or a sock aid to help you put on and take off your shoes and socks without bending over. Also, a extension reacher or grabber may be helpful for picking up objects that are too low for you to reach.
- When lying in bed, place a pillow between your legs to keep the joint in proper alignment.
- A special abductor pillow or splint may be used to keep the hip in correct alignment.
- An elevated toilet seat may be necessary to keep the knees lower than the hips when sitting on the toilet.