Like any operation there are significant risks of having a knee replacement operation.
Thrombosis: This is a technical term for a blood clot. Orthopaedic surgery in general, and knee and hip replacement in particular, carry a recognised risk of producing a blood clot in the veins of the leg. Sometimes the blood clot may form inside the veins of the pelvis. While the clot is not dangerous in itself, it can break off and travel with the blood stream to lodge itself in another blood vessel in the lungs or in another organ such the heart or the brain. In so doing, it may stop the blood flow to that organ and damage it with serious adverse effects and may even be fatal. The risk of a fatality is about 2-3 in a thousand with the precautions that are nowadays standard practice. The surgical stockings given to patients for use before and after surgery reduce the chances of developing a blood clot. Research has shown that encouraging patients to start walking early on after their operation also helps to avoid a blood clot as does the use of blood thinners after surgery. Mr Trakru's practice is to have the physiotherapists help the patients start walking on the day after their surgery and to routinely use blood thinning injections during the entire time that patients are in hospital.
Infection: The precise rate of infection across the U.K. is not known but is likely to be about 2-5%. In order to reduce the risk of infection, patients are given antibiotics routinely into the vein just prior to the surgery and a further two doses after. Scientific studies have shown that antibiotics given in this manner play a significant role in avoiding infection. To learn more about infection after surgery, click here.
Nerve injury: It is fairly common after surgery for patients to notice that the feeling in the skin to the outer side of the scar on the front of the knee is not quite normal. Often this is described as somewhat 'dead' or similar to the feeling when the leg 'goes to sleep'. This occurs because the nerve responsible for enabling feeling in this part of the skin is fairly thin and often gets damaged while making the cut in the skin. With time, the area of the skin so effected tends to reduce in size. Of course, the function of the replaced knee joint is unaffected by this complication.
Rarely, knee replacement surgery can produce an injury to the main nerve of the calf called the common peroneal nerve. The likelihood of the nerve damage is higher where the leg has had a severe knock knee deformity prior to the surgery as "straightening" of the leg may stretch the nerve. The risk of such an injury is about 2 or 3 out of a thousand. Such a patient may notice that he or she is unable to pull the ankle and foot upwards or downwards or both and that the feeling in the skin in the calf or shin area or the foot may not be quite normal. He or she may be aware of patches of numbness or pins and needles. In the unfortunate situation when the injury does occur, it usually involves only a portion of the nerve and is sometimes reversible.
Stiffness: The artificial knee joint does not have the ability to bend as does the natural knee. However, most patients are able to bend the knee to just over a right angle or 90 degrees and that is sufficient to enable them to carry out normal day to day activity. This range of movement enables them to walk, climb stairs, sit in a chair, cycle and swim. A minority of patients may however find that their knee does not bend as much and the occasional patient may not be able to straighten the knee fully. This stiffness arises from the scarring of the soft tissues after the operation.
Loosening of the artificial knee: The artificial knee may not last for ever. After some time it does not remain fixed to the bones of the skeleton as well as it was soon after the surgery. This explains the term 'loosening'. The problem is more prevalent on the shin bone side than on the thigh bone side. It is however, uncommon for loosening to occur before 10 years from the surgery. More recent advances in technology and technique of surgery suggest that future results may be better compared with previous ones, but the medical profession will know this for sure only with the passage of time. From the patients perspective, loosening of the knee can result in pain. Often this pain is worsened by bearing weight and by walking. The patient may notice a gradual recurrence of the deformity in the leg that he or she had prior to the surgery. Some patients report a feeling of instability or clunking from the knee and the leg seems incapable of supporting their weight. Often the knee joint may swell and feel warm to the touch. If the components of the knee are definitely loose on X-rays then it is likely that your specialist will recommend a 'redo' or a revision operation. This is to control the pain and to prevent damage to the bone from the loose knee. Occasionally, the knee may loosen without the patient experiencing any symptoms and that is why patients are advised to stay under permanent review and to have X-rays time to time to check their operated knees.
Wear of the artificial knee: This is a relatively uncommon complication with the currently available designs of knee replacements. With the earlier designs, the UHMWPE (plastic) bearing appeared to have a tendency to wear out within a few years. The process causes the formation of fine particles of UHMWPE which in turn has the potential of producing inflammation of the soft tissues, loosening of the components and damage to bone. Unfortunately, some 'improvements' that were introduced by a few manufactures for theoretical reasons that seemed to have every likelihood of working well were later found to not do so well at all when implanted into the human body. These components have since been discontinued. With improved understanding of the process, modern designs have features that reduce the risk of wear. Further, improved surgical techniques used at the time of implantation of the knee replacement also reduce the chances or rate of wear.