Understanding Risk Series - Total and Partial Knee Replacement Surgery
It is important to understand the options and risk and complications of surgery:
Total knee and partial knee replacements are usually performed on patients suffering from severe arthritis where the pain interferes with normal day to day activities and require the use of pain killers. Most patients are above the age of 55yrs. Before moving to the option of surgery it is important to have tried and considered the other non-surgical possible options.
The option of a partial knee replacement is made on the basis of the degree of osteoarthritis within the knee joint. If it is isolated to just one area, we will offer a partial knee replacement. This is verified initially on an MRI scan but ultimately decided when the surgery takes place. We always have the plan B and an option to divert to a total knee replacement if the other parts of the knee are more worn than expected on MRI or the ligaments are not intact allowing us to safely perform a partial knee replacement.
The national joint registry shows that the revision (redo) rate for partial knee replacements are higher than that for total knee replacements over a 7-10 year period. (Approx. 3% vs 6%).
Other alternatives include:
stopping strenuous exercises or work
Physiotherapy and gentle exercises,
Medicines, such as anti-inflammatory
Using a stick or a crutch
Using a knee brace
All surgery and treatment carry some risk these are the most common for a total and partial knee replacement:
Most Common 2-3% or higher risk of occurring
Pain: the knee will be sore after the operation. If you are in pain, it’s important to tell staff so that medicines can be given. Pain will improve with time. Rarely, pain will be a chronic problem. This may be due to altered leg length or any of the other complications listed below, or sometimes, for no obvious reason. 1 in 10 patients can have worse pain after surgery than before that con be permanent. Some patients will regret having surgery and wish they had not proceeded.
Bleeding: A blood transfusion or iron tablets. May rarely be required. Rarely, the bleeding may form a blood clot or large bruise within the knee which may become painful require an operation to remove it (Haemarthrosis).
Blood clots: a DVT (deep vein thrombosis) is a blood clot in a vein. The risks of developing a DVT are greater after any surgery (and especially bone surgery). DVT can pass in the blood stream and be deposited in the lungs (a pulmonary embolism – PE). This is a very serious condition which affects your breathing. We will give you medication to try and limit the risk of DVTs from forming. We will also ask you to wear stockings on your legs and may use foot pumps to keep blood circulating around the leg. Starting to walk and moving early is one of the best ways to prevent blood clots from forming. A DVT may be life threatening.
Knee stiffness: may occur after the operation, especially if movement post-operation is limited. Manipulation of the joint (under general anaesthetic) may be necessary.
Less Common Risks Less of occurring 1%:
Infection: You will be given antibiotics just before and after the operation and the procedure will also be performed in sterile conditions (theatre) with sterile equipment. Despite this there are still infections (approx. 1%). The wound site may become red, hot and painful. There may also be a discharge of fluid or pus. This is usually treated with antibiotics, but an operation to washout the joint may be necessary. In rare cases, the prostheses may be removed and replaced at a later date. The infection can sometimes lead to sepsis (blood infection) and strong antibiotics are required. The worst case would be that this infection could be a risk to your life or require you to lose your leg above the knee.
Prosthesis wear: Modern operating techniques and new implants, mean around 80% of knee replacements last over 15 years. In some cases, this is significantly less. The reason is often unknown. The plastic bearing is often the most commonly worn away part.
Nerve Damage: efforts are made to prevent this, however damage to the small nerves around the knee is a risk. This may cause temporary or permanent altered sensation around the knee. There may also be damage to the Peroneal Nerve, this may cause temporary or permanent weakness or altered sensation of the lower leg.
Bone Damage: the thigh bone may be broken when the prosthesis (false joint) is inserted. This may require fixation, either at time or at a later operation.
Blood vessel damage: the vessels at the back of the knee may rarely be damaged. This
may require further surgery by the vascular surgeons or very rarely amputation.
COVID 19 Risk: It is difficult to quantify at this time the true risk to developing COVID 19 due to your surgery and inpatient stay. We will ask you to isolate before and after surgery. You will also have a COVID 19 swab prior to admission. Despite this there is a risk of contracting COVID. If you did contract it having had surgery and an anaesthetic, you would be at an increased risk of developing breathing complications and this could be a risk to your life.
If you have any questions or concerns, please do not hesitate to contact us before your surgery.