Hip revision is a follow-up hip replacement operation that is performed in people whose initial hip replacement has failed. A hip revision operation is more difficult for the surgeon, involves a longer stay in hospital and has a longer recovery period than a first-time hip replacement. The problems are compounded by the fact that most patients who require hip revision are in their 70s, 80s or 90s; older patients who are frail can find such extensive surgery very difficult.
Reasons for a hip revision
Most artificial hip joints last for around 20 years but some start to fail earlier, between 10 and 15 years after the original hip replacement surgery. Common underlying reasons for needing a hip revision include:
Loosening of the joint. This can be due to cracking or destruction of the cement that holds in the ball part of the artificial hip joint, or to absorption of the bone near to the artificial joint.
Wear of the socket. It is usual for a hip prosthesis to have a plastic or polyethylene cup that forms the socket of the artificial hip joint; this can become badly scratched and worn over time.
Constant dislocation of the hip joint. This can occur because the supporting tissues around the joint become slack with age, or perhaps filled with scar tissue. Supports or braces to keep the joint in place can help but do not work well for very elderly patients, or those with some form of dementia.
Infection in the bone of the hip joint. Infection is not always due to the surgery; late infection can also occur several years later, destroying a well-functioning joint.
What does a hip revision involve?
There is more to a hip revision than simply removing the old hip prosthesis and putting in a new one. This may be possible in cases where the cement has failed, but the rest of the joint and the underlying bones are in good condition.
It is more usual for loosening of the artificial joint to be accompanied by bone changes; the femur and bone of the pelvic socket have become thin, brittle and weak and bone grafting may be necessary to provide enough healthy bone to attach a new hip prosthesis. Where bone condition is very poor, metal pins, plates and cages can be used to give additional strength.
Dislocation causes damage to the muscles, ligaments and tendons and so repeat hip replacement may not always prevent further dislocation. A locking socket may become necessary, particularly if the hip revision is done in someone with poor mobility, or who is affected by dementia and is unable to do post-surgery physiotherapy.
Hip revision after infection
This is the most challenging form of hip revision and often needs at least two operations. The first stage is to remove the hip prosthesis, and to provide a temporary replacement while antibiotics are given to clear up the infection. Deep seated bacterial infections in bone can take 3 months to treat. Once the infection is gone, a hip revision can take place but the removal of the first hip prosthesis may have caused extensive damage to the bones (infected joints are rarely loose), so grafting and the use of metal attachments are often needed.
Hip revision success rates
As you might expect, these are lower than with first-time hip replacements. A patient having a hip revision is older and therefore is less likely to recover quickly from surgery, particularly if it is difficult. Nevertheless, hip revisions are done successfully, particularly by skilled surgeons who have a lot of experience in the techniques required. After the recovery period, a hip revision can provide many years of reduced pain and increased mobility.