By Ian D. Archibald, M.D., F.A.C.S., CIME
Knee replacement surgery has gained universal acceptance for restoring the functions of walking, activities of daily living, and light recreational activities in patients disabled by arthritis. Over 300,000 of these operations are performed in the United States each year. Currently, there is a desire by both patients and physicians to accomplish this type of surgery with smaller incisions, faster rehabilitation time, and the restoration of the more normal knee function.
Total knee replacement, which is currently the preferred method of reconstructing the knee joint, resurfaces the entire joint surface. Arthritis, however, does not always involve all of these joint surfaces and may, in some patients, be confined to just one area of the knee. Total knee replacement is difficult to do through small incisions and, despite advances in rehabilitation, typical recovery times continue to take approximately two months. Further, total knee replacement does not restore as normal knee function as some people desire, especially where range of motion is concerned.
It is estimated that as many as 15 to 20% of knee replacement patients may benefit from partial knee replacement (or unicompartmental replacement). It replaces only one side of the patient’s arthritis knee, preserving two-thirds of the patient’s natural, healthy knee tissue. For patients with isolated pain indicating presence of arthritis on only one side of their knee, unicompartmental knees offer hope for long-term pain relief, faster recovery, and less scarring. The resulting knee is more natural feeling with motion that is close to normal.
Frequently asked questions:
- Who can have this alternative to total knee replacement?
Patients must have pain and arthritis changes that correspond to the same side of their knee. It is not indicated in rheumatoid arthritis, or in knees with significant deformities.
- Is this a new procedure?
No, this procedure is as old as total knee replacement itself. In the early stages of development of knee replacements, the total knee concept produced better results, and so partial knee replacements were considered only occasionally. However, with much improved implant design and the recent trend towards minimally invasive procedures, unicompartmental replacement has found a renewed interest.
- What is recovery?
Surgery time is similar to total knee replacement. The patients are usually comfortable getting out of bed and starting their therapy on the day of surgery. Approximately 50% of patients can be discharged the next day with the remaining patients needing only a second hospital day. Motion is quickly restored to the knee and the patient can usually walk without the assistance of crutches, walkers, or cane by one month. Blood transfusions are rarely necessary.
- Are there any problems?
As with total knee replacement, risks of infection, loosening, wear of components can occur. Long-term studies on these newer designs of unicompartmental replacement are not complete. Factors such as patient weight, activity, age, and lifestyle are all considered in making the decision concerning the best choice of knee replacement implant.
As with any operation, there are risks. Recovery takes time and hard work. Knee joint replacement has come a long way with considerable improvement in outcome. Unicompartmental replacement is a viable alternative to total knee replacement in SELECTED patients and attains the goals of smaller incisions, faster recovery, with more normal knee function.
Dr. Archibald is a Board Certified Orthopaedic surgeon practicing with Carolina Orthopaedic & Sports Medicine Center, P.A. in Gastonia, NC.