Blood Clots
Blood clots in the large veins (deep venous thrombosis, or DVT) of the leg and pelvis are common after knee replacement surgery. To minimize the risk of developing blood clots, your doctor will start you on blood thinning medication which will continue for several weeks following total knee replacement surgery. In addition, you will be given compression stockings to keep the blood in the legs circulating. Early mobilization after the surgery will also help prevent blood clot formation.
The concern is that if a blood clot develops, it is possible that the clot can travel to the lungs (called a pulmonary embolism), which can be potentially fatal. If your doctor finds evidence of blood clot formation, you will likely be given a higher dose of blood thinning medication for a longer period of time.
Infections
Infection of a knee replacement is a very serious complication, and may necessitate removal of the knee replacement implant. Infections sometime occur in the days and weeks following surgery (early infection), or years down the road (late infection). An attempt to surgically clear the infection, and leave the implants in place, is sometimes made, especially in the early infections. However, some infections require removal of the implants, followed by weeks of IV antibiotics. To reduce the risk of this being a problem, once you have a joint replacement you should take antibiotics when invasive procedures (such as dental work or colonoscopies) are performed.
Stiffness
When surgery is performed, you body's natural response is to make scar tissue. This is true both on the skin, and deep down inside the joint as well. Because scars contract, this can cause a tightening of the soft-tissues around the knee joint. If this occurs after a knee replacement procedure, you may have difficulty bending your knee, sitting in a chair, or walking up and down stairs. Because of this, it is important to begin bending, and fully straightening the knee, as soon as possible after surgery. Aggressive physical therapy must be continued for months following the surgery. If stiffness persists despite physical therapy, a manipulation under anesthesia may be performed. This breaks up scar tissue, but it will require you to again be aggressive with physical therapy.
Implant Loosening/Failure
Over time, implants wear out and may loosen. New technology has helped this problem, but wearing out and loosening still occur. Most knee replacements last an average of about 20 years. Some last less than 10, some more than 30. But every implant eventually wears out. This is more of a problem in younger patients, who live longer, and typically place more demands on the implanted joint.
If the joint wears out, a revision replacement (replacement of a replacement) may be performed. This is a more complicated surgery, and with each revision surgery, the life-span of the implant decreases. This is one reason why physicians often delay joint replacement surgery as long as possible, especially in younger patients.
Is knee replacement too risky?
These are some of the common complications following surgery, however, this is by no means comprehensive. Before undergoing this surgery you should have a long discussion with your doctor, and ask all your questions. You may be referred to an internist to have a full medical evaluation before surgery, and discuss any medical issues that may be unique for you.
Knee replacement surgery is outstanding--the results have been excellent and the outcome of most patients is wonderful. However, there are risks to this surgery, and it is important to understand these before you proceed.
