Total knee arthroplasty, otherwise known as total knee replacement, is a procedure where arthritic joint surfaces are removed and replaced with artificial implants. The procedure is indicated in cases of severe, end-stage degenerative arthritis and where mobility and function are significantly altered. As beneficial as total knee arthroplasty is, the surgery is not without potential for complications. These complications can range from mild to catastrophic and can occur soon after surgery or months to years later.
Infection
Infection of a total knee arthroplasty can be a serious complication. According to Herbert D. Huddleston, M.D., of the Los Angeles County Hip and Knee Institute, infections can occur early or late. Infections are caused by the invasion and colonization of bacteria in the knee joint, which now has artificial implants and no blood supply to these components with which to deliver antibiotics.
Infections can occur as a result of poor sterile technique during surgery or from a process known as seeding.
Seeding occurs when microorganisms residing in another location within the body are cast into the bloodstream where they are eventually deposited into the operated knee. It can also occur from other medical procedures such as dental cleaning where the gums, which are resplendent with bacteria, are cleaned and manipulated.
Late-onset infections can occur from chronic conditions such as recurrent bladder infections or infected sores, as seen in diabetic feet. They can surface months---even years---after the primary replacement surgery. In a 2001 study conducted by G. Peersman and colleagues and published in "Clinical Orthopaedics and Related Research," it was concluded that over 60 percent of knee infections occur three months or later after the primary surgery.
Blood Clots/Deep Vein Thrombosis
Blood clots that form in the legs after a surgical procedure are also known as deep vein thromboses, or DVTs. Clots can occur as a result of many different variables, such as the use of a pneumatic tourniquet, which restricts blood flow to the knee during surgery. Bed rest and postoperative immobility are other prevailing causes of clots.
One of the biggest dangers of deep vein thrombosis is the potential for the clot to fragment, break loose and migrate to vital organs such as the heart and lungs, causing what is known as a pulmonary embolus, or PE.
Preventive measures can greatly reduce the potential for DVTs, such as the use of postoperative anticoagulant drugs such as aspirin and Coumadin, as evidenced in a study conducted by Bernard N. Stulberg and colleagues and published in the "The Journal of Bone and Joint Surgery."
Implant Loosening
Components of a knee replacement can become loose for a number of reasons, including improper surgical technique and from abnormal wear over time. Once components become loose, there is no option but to remove them and revise the replacement.
Implants are secured to the patient's bone in one of two ways: cementless, where the implants are fitted extremely tight against the bone so as to stimulate bone healing to the actual implant, and cemented, in which case the implants are secured to the host bone by special grout-like cement. Loosening can occur between the implant and the cement, the implant and bone, or between the bone and cement.
Implant Breakage
Breakage of individual components of a knee replacement can be a devastating complication, as it can cause damage to the other components if not treated properly. The most common components to break are the plastic tibial, or shinbone, spacer and the patella, or kneecap, implant, which is also plastic.
Breakage can be caused by such factors as improper surgical implantation that causes abnormal stress and wear patterns, obesity, trauma, and product failure. Inadequate bone strength can also lead to breakage.
Excessive Joint Stiffness
Patients with severe arthritis seek joint replacement to provide improved motion to the knee. According to the American Academy of Orthopedic Surgeons, severe pain that limits everyday activities such as walking and loss of mobility and the need for assistive devices such as canes and walkers are good reasons to consider a knee replacement.
In some cases, stiffness of the joint can occur after knee replacement surgery, which can be more severe than what it was before surgery. Stiffness can occur for many reasons, including lack of motion immediately after surgery or excessive scar tissue development.
