Risks of Total Knee Replacement

As with all procedures, this carries some risks and complications.

Common: (2-5%)

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 and may be due to any of the other complications listed below, or, for no obvious reason. Rarely, some replaced knees can remain painful.

A blood transfusion or iron tablets may occasionally be required. Rarely, the bleeding may form a blood clot or large bruise within the knee which may become painful  and require an operation to remove it.

Deep vein thrombosis (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. Your surgeon may give you medication to try and limit the risk of DVTs from forming. Some centres will also ask you to wear stockings on your legs, while others 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.

Knee stiffness
May occur after the operation, especially if the knee is stiff before the surgery. Manipulation of the joint (under general anaesthetic) may be necessary.

Prosthesis wear
With modern operating techniques and new implants, knee replacements last many years. In some cases, they fail earlier. The reason is often unknown. The plastic bearing is the most commonly worn away part.

Less Common: (1-2%)

You will be given antibiotics at the time of the operation and the procedure will also be performed in sterile conditions (theatre) with sterile equipment. Despite this infections still occur (1 to 2%). 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 and 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.

Rare: (<1%)

Pulmonary embolism
A pulmonary embolism is the spread of a blood clot to the lungs and can affect your breathing. This can be fatal.

Altered leg length
The leg which has been operated upon, may appear shorter or longer than the other.

Altered wound healing
The wound may become red, thickened and painful (keloid scar) especially in Afro-Caribbeans.

Joint dislocation
If this occurs, the joint can usually be put back into place without the need for surgery. Sometimes this is not possible, and an operation is required, followed by application of a knee brace.

Nerve damage
Efforts are made to prevent this, however damage to the small nerves of 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. Changed sensation to the outer half of the knee may be normal.

Bone damage
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. may require further surgery.

This very rare complication may occur after any major surgery and from any of the above.