Infection

• The most obvious, most worrisome and deadliest problem that can occur with a knee replacement is infection. Whenever bone is cut and replaced with man-made material, it is a magnet for bacteria and infection. Even though huge efforts are made to avoid infection, it can and does happen in rare instances. Signs of infection include heat in the joint; an incision that is red and pussy and seeping discolored fluid (yellow is a normal fluid, thick green mucus is NOT); tenderness in the joint along with swelling; and fever in the patient. If these symptoms occur, it is imperative to get into your doctor as soon as possible. An infection in your replaced knee is no joke and could cost you your life.
  
  

Swelling and Bruising

• While this may seem obvious, patients who undergo knee replacement surgery are often shocked that the bruising and swelling will extend from the tops of their thigh to the bottom of their foot, and can last for weeks. Knee replacement surgery is very violent and physical. Hammers, saws, screws, pins and sheer muscles are used to wrench, cut, pound, remove and replace bone and sinew. The poor soft tissues surrounding the kneecap and the leg bones will receive the brunt of this attack, and they react accordingly. While every surgeon does her best to minimize damage to surrounding tissue, it simply cannot be helped. Be prepared for this going in.
  
  

Rehab

• This may seem like a strange "problem" to have with total knee replacement, but for many, rehabilitation can be very intimidating. The necessity of flexing, moving and manipulating the still healing flesh, while enduring excruciating pain during the process, can be overwhelming for some patients. A visit to a physical therapist office where other knee replacement patients are being "worked" can make this impression even worse than it is. The sight of another person, writhing in pain, while a therapist works their still fresh wound, can be frightening. But it is important to realize that this is the single most important part of recovering from total knee replacement surgery. Without the help of a professional physical therapist, your hopes of a normal life after the surgery are severely limited.
  
  

Numbness

• Another problem often encountered with total knee replacement surgery is the loss of feeling of a significant section of the lower leg. This can be permanent. During the surgery, the main nerve must be cut in many cases to provide the workspace for the surgeon. While feeling can return over time, there are no guarantees. When the nerves are not responding as they should, a section of the leg will feel "numb" and touch in that area is often unpleasant. As the nerve begins to knit, the patient can sometimes feel itching that he cannot alleviate, and tingling, as well as burning and other unpleasant sensations. There is little that can be done except to understand that the feelings are temporary. If they persist, see your surgeon.
  
  

Joint Failure

• In very, very rare cases, the replaced knee joint will fail. The symptoms to this, as you can imagine, are fairly obvious. The single most common reason for a failed knee replacement is infection in the joint. But other, less common, occurrences can lead to failure. Trauma or bone fracture, or faulty prosthetic materials, can cause the failure of a knee replacement. In all these cases, the patient will not be able to function and medical intervention will be necessary.