As with all major surgical procedures, complications can occur. Some of the most common complications following knee replacement are:

• Thrombophlebitis
• Infection
• Stiffness
• Loosening

This is not intended to be a complete list of the possible complications, but these are the most common complications.

Thrombophlebitis
Thrombophlebitis, sometimes called Deep Venous Thrombosis (DVT), can occur after any operation, but is more likely to occur following surgery on the hip, pelvis, or knee. DVT occurs when the blood in the large veins of the leg forms blood clots within the veins. This may cause the leg to swell and become warm to the touch and painful. If the blood clots in the veins break apart, they can travel to the lung, where they get lodged in the capillaries of the lung and cut off the blood supply to a portion of the lung. This is called a pulmonary embolism. (Pulmonary = lung, embolism = fragment of something traveling through the vascular system). Most surgeons take preventing DVT very seriously. There are many ways to reduce the risk of DVT, but probably the most effective is getting you moving as soon as possible! Some of the commonly used preventative measures include pressure stockings to keep the blood in the legs moving and taking medications that thin the blood and prevent blood clots from forming.

Infection
Infection can be a very serious complication following an artificial joint replacement surgery. The chance of getting an infection following artificial knee replacement is probably somewhere around 1%. Some infections may show up very early - before you leave the hospital. Others may not become apparent for months, or even years, after the operation. Infection can spread into the artificial joint from other infected areas.

Stiffness
In some cases, the ability to bend the knee does not return to normal after an artificial knee replacement. We use a machine known as a CPM (continuous passive motion) machine immediately after surgery to try and increase the range of motion following artificial knee replacement; however, we rely on physical therapy beginning immediately after the surgery to regain the motion. To be able to use the leg effectively to rise from a chair, the knee must bend at least to 90°. A desirable range of motion should be greater than 110°. Balancing the ligaments and soft tissues (during surgery) is the most important determining factor in regaining an adequate range of motion following knee replacement, but sometimes increasing scarring after surgery can lead to an increasingly stiff knee. If this occurs, we may recommend taking you back to the operating room, placing you under anesthesia once again, and forcefully manipulating the knee to regain motion. Basically, this allows us to breakup and stretch the scar tissue without you feeling it. The goal is to increase the motion in the knee without injuring the joint.

Loosening
The major reason that artificial joints eventually fail continues to be a process of loosening where the metal or cement meets the bone. There have been great advances in extending how long an artificial joint will last, but all will eventually loosen and require a revision. A loose prosthesis is a problem because it causes pain. Once the pain becomes unbearable, another operation will probably be required to revise the knee replacement.