Total knee replacement surgery is a procedure designed to resurface degenerated, arthritic surfaces of the knee joint. The goal is to relieve pain and improve function. For countless numbers of people who suffer from the ravages of arthritis, total knee replacement can be a quality-of-life-improving surgery. For all the benefits that total knee replacement surgery can give those who suffer from pain and mobility difficulties from advanced arthritis, the procedure does not come without its share of potential complications and problems. Those considering this procedure should make themselves aware of the risks and potential problems as well as the significant benefits.
Infection
One of the most common problems after total knee replacements is infection. While it is the most common complication, it is still a rarity. The American Association of Orthopaedic Surgeons reports that serious infections occur in less than 2 percent of those undergoing the procedure. Infection typically occurs when harmless microorganisms that normally occupy the outer layers of the body opportunistically invade the deeper tissue layers as a result of a break in the integrity of the skin---in this case, a surgical incision.
Microorganisms can be inserted into the body from a variety of means, such as seeding, where bacteria enter the bloodstream at a distant or remote location and travel to the surgical site, which is compromised by the presence of artificial implants and altered blood supply, improper sterile technique or contaminated instrumentation, and other systemic diseases or conditions such as pneumonia.
Blood Clots/Deep Vein Thrombosis
Deep vein thrombosis, or DVT, refers to the formation of blood clots in the deep veins of the lower extremities, most frequently in the calves. There is a definite risk of clot formation following knee replacement surgery. Factors contributing to clot formation include bed rest; immobility; the use of tourniquet ischemia, which means using a tourniquet to stop the flow of blood into a leg during joint replacement; and profound vascular relaxation from spinal anesthetics.
In a 2000 study of 100 patients conducted by the Department of Anesthesia and Surgical Intensive Care at Singapore General Hospital, researchers documented an overall DVT incidence rate of approximately 40 to 80 percent in Western culture when not treated prophylactically, before and after surgery. The incidence was higher in patients receiving bilateral knee replacements, meaning they are implanted in both legs.
Component Loosening
Prosthetic components can become loose over time, causing considerable aggravation. Loosening of the implants typically occurs in locations where the implant and host bone interface, where bone cement and host bone interface, and where the cement and bone interface each other. Loosening can take place as a result of improper implantation, in which case there are abnormal forces applied to the components that would ordinarily not occur if implants were inserted and balanced properly. Components can also loosen over time as a result of wear, explains AAOS, causing microscopic particles of polyethylene plastic in the joint fluid to migrate into the interface of the implant and cement, or implant and bone, resulting in loosening.
Implant Breakage
Implants can break due to a variety of reasons: improper implantation; defective metal and plastic manufacturing; and thinning of the polyethylene plastic insert between the tibia, or shinbone, and the femur, or thighbone, from long-term or abnormal wear.
Loss of Motion/Stiffness
It is normal for patients to expect some level of stiffness during the healing and rehabilitation phase after knee replacement surgery. Stiffness becomes a complication and problem if it persists and does not improve.
Alejandro González Della Valle, M.D., assistant professor of orthopedic surgery at Weill Medical College at Cornell University reports knee stiffness prevalence rates of 5 to 7 percent after knee replacement surgery. Causes of postoperative stiffness can range from technical errors in implantation to systemic response to inflammation caused by the surgery itself.
References
- American Association of Orthopaedic Surgeons: Total Knee Replacement
- "Annals of the Academy of Medicine, Singapore"; Deep Vein Thrombosis After Knee Replacement Surgery; P. Ruban; July 2000
- American Association of Orthopaedic Surgeons: Cemented and Cementless Knee Replacement
- Total Joints: Total Knee Complications
- Ortho Super Site: The Stiff Knee: A Frustrating, Post TKA Challenge
