A knee replacement surgery usually guarantees a life period of 20 - 25 years. But like any other part, it will undergo wear and tear during this period.
The first three reasons mentioned above are surgeon and technique related and can be avoided by adopting meticulous techniques and using high-end technology like computer assistance. Computer helps in correct positioning of the new knee and achieving accurate limb alignment after surgery. It also helps in proper balancing of ligaments around the knee joint.
Henceforth we can safely say that with the advent of computer-assisted surgeries, the technical issues have been ironed out and fewer Revision Knee Replacement surgeries are performed to rectify the failure of earlier surgery.
The fourth cause which in fact is yet another important reason for early joint failure is infection, which can happen either within few weeks after surgery (early infection) or can happen even months or years after surgery (late infection).
Infection can lead to failure of knee replacement, requiring revision surgery but this is a rare complication occurring in less than 1% of the patients. An infected artificial knee joint might become swollen, painful and inflamed, discharging fluid or pus. Sometimes the patient may complain of persistent pain and the joint may look otherwise normal. In such cases various lab tests and scans are done to confirm the diagnosis. In long standing infection the implant might start losing its attachment to the bone leading to serious dysfunction.
We can prevent infection by utilizing the following measures:
1. A well-equipped operation theatre which has laminar flow with HEPA air filter 2. Use of Space suit to avoid the spread of infection 3. Use of disposable items, wherever possible 4. Use of antibiotics, as per the norms. 5. Proper control of diabetes in diabetic patients, before surgery.
We perform a two-stage procedure for the infected knee, which is a normal procedure followed by most surgeons.
In the first stage, we remove the infected knee and fill it with antibiotic cement spacer. The patient will be provided antibiotics for a minimum period of 3 months. We will then wait for the infection to subside, which might take 6 months and maybe a year. In the meantime, the patient can walk and perform routine activities that include the bending of the knees.
After the initial period of six months to a year, we do a set of blood tests to confirm that there is no residual infection. In the second stage, we then remove the cement spacer and put the new knee.
Other uncommon causes for failures include,
• Mismatch of the gaps • Leaving the knee-cap bone without resurfacing • Fracture after knee replacement • Stiff knees and other causes
The technical issues can be treated by surgery that might include one or more of the following procedures.
1. Insertion of Exchange 2. Revision of the leg bone component 3. Revision of the thigh bone component 4. Resurfacing of the kneecap
5. Total Revision of the knee replacement.