Total Knee Replacement or Arthroplasty (TKA)
In this technique all three compartments of the knee are replaced with synthetic materials, usually metal and plastic. This procedure allows the surgeon to correct any bony deformities or malalignments that may exist. At the same time any muscular or ligamentous contractures can also be corrected.
- Soft tissue balancing. Motion to the knee is restored by balancing the muscular and ligamentous elements.
- Bony correction. The diseased joint surfaces are removed using a saw. This must be carefully done to allow for the precise fitting of the prosthetic knee components
- Inserting the artificial knee. In most cases a special bone cement is used to hold the knee components onto the remaining bone. In some cases the components may be press-fit on without the use of cement.
- Motion and Stability. The cuts and component fittings must be done to achieve a balance of good stability but still with enough flexibility to allow good motion. This is where much of the art of this procedure takes place.
Success Rates. The ten year success rate for total knee replacement is in excess of 90%. All else equal knee replacements last longer in older than younger patients because the latter are more active. The procedure is very effective in drastically reducing pain during walking to allow older patients to resume the active lifestyle that is important in maintaining good health.
Complications. Loosening of the prosthesis over time results in pain and necessitates revision. Many patients, especially those over 65 may never experience this problem.
Infection occurs in about 1% of patients and requires further surgery and often the implantation of a new prosthetic knee. Success rates are generally good.
Kneecap pain or instability can also occur in some patients and may require further surgery. Other complications can rarely occur.