Knee replacement has become a common elective surgery for people suffering from knee arthritis. The operation is performed for relieving pain and to help the patient to live a more active and productive life. Although most of the knee replacement operations are successful, there is slight possibility of rejection.
Failure of knee replacement can be due to pathologies such as infection, malposition of the component due to loosening of the artificial implant, impingement of soft tissue or inadequate balancing.
In all the rejection cases pain is one of the most prominent symptoms besides instability and swelling after the surgery.In case of rejection a corrective surgery may be needed. Talk to your doctor if you have any of the symptoms persists for a period of time after the surgery.
Causes Of Knee Replacement Failure
Knee replacement nowadays is the most common surgery performed all over the world for severe osteoarthritis of knee joint. Knee joint replacement is actually a procedure in which the damaged knee joint is replaced by an artificial prosthesis. This prosthesis is made of partly by metal, plastic and polymer. After the replacement it functions just like an actual knee joint.
As with any surgery, total knee replacement surgery also carries some percentage risk of rejection or failure. However, the percentage is very small. Following are some of the reasons for knee replacement rejection:
- Infection: The artificial knee joint can be infected at the time of surgery or anytime afterwards. Infection in the replaced joint can occur even after months and years of the operation. It is mostly a bacterial infection. Since the replaced joint is made up of metal and plastic, the germs once infiltrated can easily latch onto it. The immune system fails to kill the germs once they get access into the implant because it is made up of plastic and metal. Bacteria start multiplying leading to infection and pus. Infection in the replaced knee can also spread from other infected site in the body. For example the bacteria can spread from cuts and wounds on skin at some other site. Bacteria can also spread from infection in tooth. People at higher risk are those suffering from diabetes, immune deficiency, obese, and those suffering from peripheral vascular disease.
- Loosening of the artificial knee joint due to regular wear and tear can lead to failure. It can occur when the surface of the implant rubs against each other making the implant lose.
- Fracture around the knee joint can result in instability of the joint. It may need a revision surgery.
Signs And Symptoms Of Knee Replacement Rejection
After the surgery for total knee joint replacement, the patient normally feels his knee stiff and painful for few days or few weeks. But with painkillers and long standing anesthetic block will help to relieve the post operative pain. Patient will be given several other medicines to reduce pain and swelling. Physiotherapy exercise is started within a day. It is usually passive physiotherapy intended to promote proper blood flow into the replaced knee.
Although in majority of patients the surgery is successful, in some it can be a case of rejection. Patient must be aware of the symptoms of rejection. Most cases of rejection occur due to infection. The signs and symptoms of failure are as follows:
- Severe and unbearable pain in the operated knee joint.
- Presence of stiffness in the knee that is more as compared to stiffness before the surgery.
- Swelling around the knee because of infection and formation of pus.
- The area around the operated site becomes red and warm.
- Some patients feel instability of the joint. They feel as if the knee will give away while walking or standing. This can occur due to wear and tear of the plastic part in the knee prosthesis. The ligaments become loose and leading to instability of the joint.
Treatment For Knee Replacement Rejection
In some cases the infection is limited on the superficial part of the skin and the soft tissue. It may not have spread deep inside the knee joint. The doctor will try to treat this superficial infection conservatively with antibiotics. Usually intravenous antibiotics are preferred for few days to control the infection. It may be followed by oral antibiotics once the infection is controlled.
If the infection has spread deep inside the artificial knee joint it will require surgical intervention. If the condition is in its early stage, surgical washout may be enough. Once the infected soft tissue is removed, the doctor will clean the artificial implant. This will be followed with a course of intravenous antibiotics.
If the infection has been for over a period of time, the implant may have to be removed and new implant will be inserted over a period of time.