Total knee replacement is a major surgical procedure and there are innumerable potential complications. In aggregate, the benefits (improvement in the patient's quality of life) of total knee replacement outweigh the risks (the chance of that patient having a complication) for most individuals with severe knee arthritis. Most patients have many years of painless knee function. If you wish to receive the benefits of total knee replacement, you must also be willing to accept the risks. The decision to undergo total knee replacement surgery is yours.
The following is a list of possible risks potential complications of total knee replacement surgery. These are merely possibilities which we feel patients ought to be aware of before deciding upon total knee replacement surgery.
Total joint replacement is a major surgical procedure and requires either regional or general anesthesia. Regional anesthesia involves a spinal or an epidural administration of medicine that creates numbness below the waist. With general anesthesia, medication is given which circulates throughout the entire body and causes complete loss of consciousness. The risks of anesthesia are related to your general medical condition (not your age) and the function of vital organs such as the heart, the lungs and the kidneys. A thorough discussion of these risks can be conducted by an anesthesiologist. Although extremely rare, patients can die from complications related to anesthesia.
Bleeding / Blood Transfusion
There will be some bleeding as a result of the surgical procedure. For this reason, you will be asked to donate some of your own blood before surgery. If you should need a blood transfusion, you could then receive your own blood. A family member can donate blood for you before surgery (it takes 2 to 3 days to process the blood), but it may not match your blood type closely enough for you to receive it. Rarely, there can be bleeding complications related to surgery. In that case, it may be necessary to transfuse blood from the Red Cross blood bank. With any blood transfusion, there is always a small risk of a transfusion reaction or disease transmission. Major transfusion reactions are, fortunately, quite rare. The risk of transmitting HIV is about 1 in 150,000. To put this in perspective, you are actually more likely to be struck by lightning. The risk of hepatitis is greater than that of HIV, about 1 in 30,000 to 1 in 50,000. Fortunately, permanent liver damage is rare. Please refer to the section entitled "Planning for Your Surgery" for additional information regarding autologous, homologous and banked blood.
Blood clots can form in the large veins of the legs and pelvis following major surgery, such as total knee replacement. It is possible for such a clot to break loose from the vein and travel to the heart. The clot can pass through the heart and into the lungs. This is called a pulmonary embolus. Rarely, a pulmonary embolus is fatal. In order to minimize the chance of the formation of blood clots, and subsequent pulmonary embolism, we routinely give anti-coagulation medicine following total knee replacement surgery. The anti-coagulation medicines carry a risk of increased bleeding, especially at the surgical site (inside the knee). The risk of increased bleeding is, however, more than counter-balanced by the protection against blood clots provided by the anti-coagulation medicine.
Table 1 - Factors That Increase The Risk of Thromboembolic Disease
·Collagen vascular disease
·Congestive heart failure
·Previous thromboembolic episodes
Table 2 - Factors That Decrease The Risk of Thromboembolic Disease
·High vitamin K diet
Infection can occur following any type of surgery. In order to minimize the potential for infection to occur at the time of surgery, antibiotics are given before surgery and for 1 to 2 days following the operation. Infection following total knee replacement is of special concern because of the prosthetic components. The prosthetic components have no blood supply and this makes them susceptible to infection. If the prosthetic components become infected, additional surgery is almost always required in order to treat the infection. Sometimes the infection can be treated without removing the total knee replacement components. In some cases, however, they may need to be removed in order to eradicate the infection. Intravenous antibiotics are generally administered for about 6 weeks in order to treat the infection. Once the infection is treated, new components can generally be implanted. If there is concern that the infection cannot be eliminated, then a knee fusion (arthrodesis) may be recommended.
The risk of infection persists for as long as the total knee replacement is in place. The most common way that a total knee replacement becomes infected is by spread of bacterial infection from another location in the body. Bacterial infections may be spread from the mouth because of a dental infection; from a urinary tract infection; as a result of pneumonia; from a skin infection; or even an in-grown toenail. It is very important that any bacterial infection be treated promptly in order to minimize the chance of spread to the total knee replacement. It is also recommended that antibiotics be taken before any dental procedure, although the need for special precaution during routine dental check-ups is controversial. If possible, any anticipated major dental work should be completed before total knee replacement surgery or deferred for at least four months after surgery. You should inform your dentist that you have a total knee replacement. Similarly, antibiotics should be given if you are going to have any type of invasive procedure such as an endoscopy or bronchoscopy. Viral infections, such as a cold or flu, do not infect total knee replacements.
Blood Vessels and Nerves
There are several major blood vessels and nerves around the knee. Rarely, a major blood vessel or nerve is injured during total knee replacement surgery. An injury to a blood vessel can usually be repaired at the time of surgery. Nerve injuries may not be recognized at the time of surgery. Nerve injuries associated with knee replacement surgery can result in numbness and weakness, usually around the foot. Such nerve injuries may or may not require surgical repair, and the nerve usually recovers over a period of several months, however, the injury is occasionally permanent.
While more than 90% of patients have complete or nearly complete relief of pain following total knee replacement, there are some patients with some persistent pain. In many cases, the pain resolves with time. In other cases, a specific cause for the pain can be identified and treated. This may involve the patella and occur with deep bending or forceful straightening of the knee. Sometimes this requires additional surgery. It should be recognized that there are many causes of pain and, rarely, patients can have pain even if the knee replacement is well-fixed and well-functioning.