As with all surgical procedures certain risks are involved after knee replacement. 

The complication rate following knee replacement surgery is low. Serious complications, such as joint infection, occur in fewer than 2% of patients. Major medical complications, such as heart attack or stroke, occur even less frequently. Chronic illnesses, however, may increase the potential for complications. When complications occur they can prolong or limit full recovery.

Blood clots in the leg veins are the most common complication following knee replacement surgery (see picture). The AAOS recommends one or more measures to prevent blood clots from forming in your leg veins or, if they do form, measures to prevent them from becoming symptomatic. These measures will include support hose (TED hose), inflatable leg coverings (SCD’s), ankle pump exercises, early mobility after surgery, and a blood thinner (Aspirin, Coumadin or Lovenox).

After surgery you are at risk for Pneumonia. Your nurse will instruct you on the use of the Incentive Spirometer to help expand your lungs and significantly reduce your risk. You will also be asked to cough and deep breathe. Early mobilization and discharge are also effective ways to limit your risk of pneumonia.

Although implant designs and materials as well as surgical techniques have been optimized, wear of the bearing surfaces or loosening of the components may occur. Additionally, although an average of 120° of motion is generally anticipated after surgery, scarring of the knee can occasionally occur, and motion may be more limited, particularly in patients with limited motion before surgery. Finally, although rare, injury to the nerves or blood vessels around the knee can occur during surgery causing numbness or foot drop.