For those who suffer from end-stage arthritis of the knee, joint replacement can be a life-altering procedure. It can restore mobility that has been lost due to stiffness and pain, and people can reclaim their lives. That being said, knee joint replacement does not come without risk. Joint replacement of any kind has a unique set of potential hazards and complications that require the recipient to be ever vigilant in order to preserve the restored function and reduced pain.
Infection
Any surgical procedure carries a risk of infection, but infection in an artificial joint can be catastrophic. It can result in loss of the prosthetic components, a limb or even a life. The main reason infection in a joint that has been replaced is becuase prosthetic implants have no inherent blood supply to carry important antibiotics to the area in cases of infection. The same can be said for implants that have been cemented into place, as there is no blood supply to breach the barrier of the artificial surfaces. Bacteria, once established in an artificial joint, can flourish much easier than in a regular biologic joint.
The end result is an infection that may very well require complete removal of all implants and specialized temporary spacers inserted into the joint, impregnated with antibiotics, to help fight off the infection until such time as new implants can be reinserted.
Blood Clots
One key risk associated with surgery of the lower extremities is blood clots in the deep veins of the legs, also known as deep vein thrombosis (or DVT). The clots can form as a result of prolonged immobility, the use of a tourniquet during surgery to keep the operative site free of blood and dilatation of the veins and arteries in the legs secondary to anesthetics and surgery.
DVT's ihave the potential of breaking away from the vein they reside in and following the venous circulation up into the heart and lungs. This can result in what is called a pulmonary embolus, or PE. Pulmonary emboli can be dangerous and even be fatal if the clot is large enough.
Loosening of Implants
Although very rare, premature loosening of prosthetic implants can be a serious problem. The components can move, slip and slide in the knee, causing damage to the host bone or other implants. Premature loosening typically occurs due to poor implant placement, abnormal motions of the knee, trauma as in falls in the hospital or rapid-onset infection.
Implant Breakage
Because joint replacement implants consist mainly of metal and plastic, there is a risk of fracture or breakage of the plastic. The plastic component in a knee replacement can break due to improper insertion or sizing, too thin of a spacer, which can cause abnormal wear on the plastic with ultimate breakage a distinct possibility, or trauma such as a fall directly onto the knee.
Stiffness
Stiffness after knee joint replacement surgery is always a potential risk due to the magnitude of the procedure and the degree of soft tissue dissection. Pain is also a mobility inhibitor. To combat stiffness, physical therapy is started very early on in the recovery phase and is continued long after the patient has returned home. Rehabilitation of this type focuses on stretching and maintaining as much flexion, or bending ability, as possible. Once stiff, it can be difficult to impossible to regain the motion.
