Revision Total Hip Replacement

Modern hip replacement has resulted in huge benefit for patients with arthritic hip disease providing them with reduction of pain, return of function and consequently an improved quality of life. The clinical success of total hip replacement is often taken for granted by the general population. There is evidence of increased longevity (twenty years or more) with some total joint replacements, but many of these mechanical joints fail at around fifteen years when the hip joint loosens. Revision hip surgery is technically extremely difficult and few orthopaedic surgeons have extensive experience in this field

What is revision joint arthroplasty?

Revision total joint replacement involves the replacement of an existing prosthesis with a new prosthesis. In total joint replacement, an original total hip replacement has two components and an original total hip replacement includes three components. A revision procedure may replace any or all of the components. The new prosthesis can be another of the original type of prosthesis (called a primary), or prosthesis especially made for revision surgery, or prosthesis especially made for your case (called a custom).

Why or when is it needed?

There are several different reasons, which may have contributed to your physician's decision to offer a revision total joint replacement. These include prosthesis failure, infection, loosening, and osteolysis (bone loss). Each of these will be discussed in the following paragraphs. However, it should be understood that these reasons for reoperation are inter-related. That is, prosthesis failure or infection may cause bone loss and bone loss may cause loosening.

Prosthesis Failure

Common cause of prosthesis failure is the wearing out of the plastic or ceramic or metal part of the prosthesis (part of the cup in hip replacement and part of the tibia shin bone in hip replacement). Techniques have been developed and prostheses are modified so that the metal parts of the prosthesis can be left in place and only the worn plastic part replaced. Plastic in use today have been developed to be stronger, wear at a much slower rate and ultimately last longer. For total hip replacement, another type of prosthesis failure occurs when the stem inside the femur (thigh bone) breaks or fractures. With our new technology, this happens very rarely. In these cases, the broken component must be removed and replaced with a similar component.

Infection

One of the primary causes for reoperation, deep infection still occurs in a small percentage of patients (less than 1%). One of the most significant adverse effects of an infection is the loss of bone surrounding the prosthesis. If this bone loss is permitted to progress, this bone loss can lead to the loosening of the implant.

Osteolysis or Bone Loss

Another primary reasons for revision total joint replacement today is osteolysis. Osteolysis is the loss of bone in the area surrounding the prosthesis. Bone loss can occur when prosthesis is loose, infected or put in incorrectly (not positioned correctly in the bone). Over the past decade, the scientific community has become aware that the development of osteolysis is associated with the accumulation of wear particles from the prosthesis. One solution to this problem is to remove the area containing the wear particles, reconstruct the bone with bone graft, and replace the prosthesis. It is important to understand that not all prostheses with worn plastic have osteolysis and not all cases of osteolysis have worn plastic. As each case is unique to the individual, you should discuss your situation with your orthopaedic surgeon.

Loosening

As we have discussed, loosening may occur when there is loss of the bone support surrounding the prosthesis. Other reasons for loosening include both patient-related and physician-related factors. For example, improper placement of the prosthesis within the bone (called malpositioning) can cause the prosthesis to function improperly and become loose. With respect to the patient, excessive activity may lead to loosening. Any of these situations requires reoperation.

Revision Hip Replacement

Revision total hip replacement is performed when the original primary total hip replacement has worn out or loosened in the bone. Revisions are also carried out if the primary hip replacement fails due to recurrent dislocation, infection, fracture or very rarely, ongoing pain and significant leg length discrepancy.

The revision total hip replacement is a more complex procedure, often because there is a reduced amount of bone to place the new total hip into. Extra bone may be required and this is usually received from a bone bank. Bone bank (allograft bone) is safe and has been irradiated to eliminate any chance of disease transmission. There are also artificial bone substitutes that may be used. Revision total hip replacement takes longer than a standard total hip replacement and has a slightly higher complication rate. The prosthesis may also not last as long as a primary hip replacement. Surgery is usually performed through the same incision but may need some extension.

Surgical Approaches

There are four approaches to the hip and access takes advantage of the muscular planes surrounding the hip joint.

• Anterior (front) Approach
  • The anterior approach has been revitalized for minimally invasive surgery (MIS) - a procedure that we Care India partner surgeon specialises in that can significantly reduce recovery time - when performing a total hip replacement.
• Lateral (side) Approaches
  • The anterolateral approach is the most commonly used approach for total hip replacements. The direct lateral approach exposes the hip joint by detaching the upper end of the thigh bone (the greater trochanter).
• Posterior (rear) Approach
  • The posterior approach is the second most common approach when performing a total hip replacement.

Approaches for Revision Hip Surgery

The approaches are the same as when performing primary hip replacements but the surgical approach can be extended to increase exposure.
Advantages
1. Relief of pain and restoration of hip function.
2. Return to a full and active life style.
Disadvantages
1. Failure of the hip implant over time.
2. Inherent risks of surgery.
Indications
Revision surgery is required for patients when the hip implant has failed.
Contraindications
1. Patients who are frail and have severe heart conditions.
2. The presence of active infection is a contraindication to hip surgery.

Possible Complications
1. Dislocation: This occurs when the ball of the femoral component is dislocated from the acetabular cup.
2. Infection: A bacterial invasion of the hip joint.
3. Thromboembolism: Blood clots and migration of the clot to the lungs.
4. Leg length discrepancy: Limb length discrepancies.
5. Fracture of femur: A crack or split/break of thigh bone.
6. Nerve injuries: Stretching, cautery or incision of a nerve.
7. Vascular injuries: Penetration or incision of an artery or vein.
8. Non-union of the greater trochanter: The upper end of the thigh fails to unite following an osteotomy.
9. Heterotopic ossification: New bone formation where bone is not normally present.
10.Stem breakage: A crack or fracture of the femoral stem.
11.Loosening: Loosening of the hip joint prostheses.
12.Wear: The erosion of the surface of two materials in contact with one another.

Recovery

The first day most patients will have had their intravenous drip removed? The physiotherapist will see you after surgery and from then on begin with muscle strengthening and stretching exercises. You will be taught the safe way of getting in and out of bed.
You will learn how to use a support and you will be encouraged to take exercise on a regular basis. By the time of discharge from around 3 to 7 days you will be able to perform all activities unassisted. You will be able to go home in a car and it may be best to have some help when you return home. Walking is good for your hip joint and excellent exercise. Non-impact sports are advisable and these include swimming, cycling and golf. Your functional ability will improve rapidly week by week until you are able to drive a car at 6 weeks.