Revision Knee Arthroplasty
A knee replacement lasts for about 20 years in the great majority of patients. Nonetheless, in a small percentage of cases, there is need for a second operation known as a revision knee arthroplasty. Reasons for implant failure vary, but once it occurs revision surgery is necessary to prevent permanent damage.
Reasons for Revision Knee Arthroplasty
Typically, after recovery from an initial knee arthroscopy, a patient will regain normal range of motion and the joint will feel stable and comfortable. A small number of patients, however, will experience pain, stiffness or limited knee function. Reasons for problems after knee replacement surgery are varied.
Overuse
In recent years, a greater number of seniors live longer and remain physically active. This, coupled with the fact that younger individuals need knee replacements sooner than their forebears because of their increasingly energetic lifestyles, means that a larger number of patients need revision knee surgery simply because they have worn their implants out.
Instability
Although implants are firmly secured to the bone during surgery, at times they can loosen. This generally results from friction within the joint. It may also occur because of an injury, such as a fracture. The chances of the knee joint becoming unstable are greater if the patient is, or becomes, obese.
Infection
Post-surgical infection is uncommon, but always a possibility after an operation. If the tissue in the knee becomes infected, a revision may be necessary even if the implant remains successfully attached.
Dislocation
Although rare, it is possible that the implant can shift out of position. If this happens repeatedly, revision surgery is necessary.
Inflammation
Though fortunately uncommon, patients who have undergone knee arthroplasty occasionally develop an inflammatory response known as osteolysis around the prothesis itself. During this erosive process, particles of plastic can break off, causing inflammation as the cells around the knee joint absorb them. This is usually the result of wear and tear, sometimes exacerbated by an uneven walking gait.
The Revision Knee Arthroplasty Procedure
Depending upon the reason for the failure of the first knee replacement and the length of time that has elapsed since the operation, the surgical incision for knee revision may be made at the same site or in a different location.
In some cases, the revision procedure will be almost identical to the first surgery. In others, however, some reconstruction of the bone is necessary, using either a bone graft or metal plates and screws to secure the implant. Once the materials are fixed in place with cement, the surgeon will drain any excess fluid from the knee joint and suture the incision.
Recovery from Revision Knee Arthroplasty
After a revision knee arthroplasty, patients' activities are restricted for 6 to12 weeks. Sometimes patients require braces for stability or assistive devices, such as crutches or walkers, to limit weight bearing and promote mobility. Physical therapy is essential for 2 to 3 months to improve knee strength and function.