Surgery and Risks
The decision to undertake surgery should not be taken lightly and ideally should be made following both the consultation with the orthopaedic surgeon and a discussion with family members. There are risks associated with the surgery and it is very important that you are aware of these.
Knee replacement surgery is a common operation and most people do not have complications. However, as with any operation, there are risks as well as benefits. 80-85% of patients are happy with their knee replacement, but this does leave a small minority who have ongoing pain despite satisfactory surgery.
Infection of joint
Infection can be a devastating complication of surgery, but thankfully it is uncommon. Infection can affect approximately 1% of patients who have knee replacement surgery.
Stiffness of the knee
The best predictor of your range of motion post-operatively is how much movement you have in the knee pre-operatively. This is why it is so important to remain as active as possible on the lead up to surgery.
On-going pain and discomfort
80-85% of patients are happy with their knee replacement, but this does leave a small minority who have ongoing pain despite satisfactory surgery. It can be a painful operation, particularly in the first few days after the procedure. The majority of pain does settle over time though. Patients usually continue to feel improvements in their replaced knee up to two years after their surgery.
Nerve damage
The skin next to the incision across the middle of the knee from the surgery often feels numb after the procedure and this can persist but doesn’t usually cause any problems. Injury to other nerves and blood vessels around the knee are rare but can very occasionally occur.
Deep vein thrombosis (DVT)
As a result of the surgery and the period of relative immobility in the knee, patients are at risk of developing a blood clot in the leg that can be thrown off to the lung. Factors that increase the risk of this include; a previous history of blood clots, a family history of blood clots and a history of active cancer. To mitigate the risk of clotting patients usually receive an injection into their tummy to thin the blood whilst they are still in hospital and then a 6 week course of aspirin after the operation.
Bleeding into the knee
When you wake from surgery there will be a bandage around the knee, with an adhesive dressing underneath. The bandage is usually taken off on the first day following the surgery. It is not unusual to get some leakage into the adhesive dressing, but if it becomes saturated then it should be reviewed by your nurse and if persistent, the surgeon. Occasionally blood can accumulate in the joint itself and require further surgery to wash out any collection. Swelling in and around the knee is very common, and indeed the knee may remain swollen for 6-12 months after the surgery.
Ligament damage
Very rarely the ligaments down the side of the knee can be injured during the procedure. If this happens, an implant which provides more stability to the knee may have to be used instead of a standard knee replacement.
Clunking of the knee
Odd noises from the knee replacement are common and it is usually the plastic in the middle of the knee tapping again the metal of the implant. These clunking noises are not usually anything to worry about.
Loosening
Modern knee replacements should last for around 15 years. They can however occasionally loosen over time, when the polyethylene (high density plastic) in the middle of the knee wears out. This is sometimes associated with pain and a sensation of instability in the knee. If this occurs a revision operation can be performed to replace the worn-out implant.
Break in bone
During or after the operation and very occasionally, the bone around the knee replacement can break. This can happen at the time of surgery or if the patient has a fall or sustains trauma to the knee, after the operation.
Additional risks
Additional general risks associated with having surgery include: Anaesthetic risk, heart attack, stroke and death. These are very uncommon, and the qualification of risk is dependent on underlying health conditions
