Knee joint replacement surgery has become increasingly prevalent over the years as a mainstay treatment for advanced arthritis. For those who suffer from the ravages of degenerative knee arthritis, the procedure can be a life-changing event. That being said, knee joint replacement, for all its benefits, is not without its risks and potential for complications. These complications can range from mechanical to systemic in nature and can, at times, be devastating.
Infection
The most dreaded complication of knee joint replacement is post-surgical infection. For all intents and purposes, there is no such thing as a minor infection in a joint that has been replaced.
Because of the artificial components, typically metal and plastic, that are implanted into the body have no blood supply to them, treating an infection with antibiotics is difficult at best. The prosthetic surfaces, as well as the types of bone cement used to adhere the components to the bone, provide a barrier against antibiotic drugs reaching the areas of microbial concentration.
Often, the only appropriate way to deal with an infection of a joint replacement is to completely remove the parts and insert temporary spacers made of antibiotic-impregnated cement for a period of several weeks before attempting to revise the joint with new components.
Loosening
The second most important complication of knee replacement, or any joint replacement for that matter, is post-surgical loosening of the implants. Joint replacement surgery requires that the patient's boners be cut and fashioned in shapes that will accommodate the near-exact fit of the corresponding implant components. This preparation creates multiple interfaces between bone and implant, bone and cement and implant and cement, all of which carry the risk of loosening.
If a component becomes loose, whether in the early post-surgery phases, or after years of usage, there is really no other remedy other than to remove the loose component(s) and re-insert new ones. On occasion, this may mean only revising one particular component, whereas other scenarios may require the complete removal of all implants and replacement with new ones, otherwise known as a revision arthroplasty.
Breakage of Plastic
Typically, the two metallic components of a knee joint replacement, the one on the femur, or thigh bone, and the other on the tibia, or shin bone, are separated by a space-age plastic spacer of sorts. This high-density plastic allows for the smooth movement of the knuckle portions of the femoral, or thigh bone, implant with no metal-on-metal friction.
Major reasons why this spacer might fracture or break, can include improper placement and balance of the ligaments during surgery, causing uneven wear and pressure on the plastic, or excessive thinning of the spacer from years of wear. In either case, removal is mandated and re-insertion of a new spacer or complete revision of all components.
Joint Stiffness
The risk of joint stiffness after knee replacement surgery is ever-present. The need for commencing physical therapy soon after surgery has gone a long way in minimizing this risk. Knee joint replacement is a major procedure and involves disruption of considerable soft tissue layers. This makes for a high risk for loss of mobility afterwards, which is why so much emphasis is placed on early rehabilitation. If a knee joint replacement becomes stiff and allowed to remain that way for an extended time, there is little hope of regaining the lost motion.
Blood Cots
Any major surgery that involves the lower extremities, especially those in which a pneumatic tourniquet is used to shut off blood supply to the extremity during surgery, carries a high risk for the development of blood clots in the leg(s), otherwise known as Deep Venous Thrombosis, or DVTs.
Blood clots in the leg(s) is a potentially serious complication, in that these clots can break loose from their locations in the legs and migrate to the heart and lungs, which can be fatal.
Considerable respect is given to this potential complication, and steps that are typically taken to reduce the potential for these clots include the used of blood thinning drugs after surgery, special stockings to aid in blood return from the legs to the heart, and early ambulation; getting out of bed and walking.
