Mobile Bearing Partial Knee Replacement
PARTIAL KNEE REPLACEMENT: This is a relatively newer surgery, not done by many surgeons. It is suited for younger patients where arthritis is limited to a part of the joint.
X-rays of both knees showing mobile bearing partial replacement
Frequently Asked Questions
- Q 1. What is partial knee replacement?
- Partial knee replacement is not at all anything like knee replacement. It should rather be called ‘capping’ operation, where caps are fixed on top of the part of the bone end. Unlike knee replacement operation where the ligaments are excised, the knee dislocated, and ends of the bones replaced, in partial knee replacement, no ligaments are removed, the knee is not dislocated.
- Q 2. What is the advantage of partial knee replacement?
- Partial knee replacement is a logical option where only a part of the knee is damaged, as putting caps only on the damaged part keeps the original joint as it is. It is much smaller and safer operation. One is up and about on legs within 3-4 days, and normal in 2-3 weeks. One need to stay in the hospital only for 2 days, and one usually gets full knee bending.
- Q 3. When we are replacing, why not replace the whole?
- Though knee replacement is a fairly successful operation in the elderly, results are not the same in younger active patients. Since all joints, partial or total have limited life, it is prudent to preserve the original joint as long as one can. Also, in case the partial joint replacement fails (which may happen with partial or total replacement), there is a back up of total replacement. Revision replacement of a failed total knee replacement is a major undertaking, not always successful.
- Q 4. How does one know that the joint is only partially damaged, and is suitable for partial knee replacement?
- There are a number of ways doctors can make out whether only a part or the whole knee is damaged. Standing x-rays give a fair idea, which is then confirmed on the operation table by doing arthroscopic viewing of the knee just prior to the actual operation. If it is found at any stage that the damage is widespread, decision of partial knee replacement is dropped in favour of total knee replacement.
- Q 5. Why there is a controversy between doctors regarding whether a total or partial knee replacement is required?
- Total knee replacement is an older operation, technically less demanding, and hence popular. Partial knee replacement is a newer operation. The earlier designs and technique of partial knee replacement were not as good, and some surgeons carry that impression inspite of the recent much improved results of partial replacement. Also, not many surgeons have exposure to the technique and understanding of the partial knee replacement, and feel comfortable doing the whole knee replacement. The latest advance in partial knee replacement is what is called ‘mobile bearing knee’ which means, between the fixed caps on the bones, there is a freely mobile plastic bearing. This causes less friction between the parts, and thus increases the life of the partial knee.
- Q 6. How much time does it take to recover?
- You are out of the bed the very next day, can take full weight on the leg , with the support of a walker. There is no plaster or bulky dressings. You can move the knee and keep it any where from the very next day. You will be sent home three days after surgery.
- Q 7. What is the negative side of the operation?
- Like with all operations there is a recovery time. There is a small risk of infection, anaesthesia related and side-effects of medication related complications. Long term problem may be that the parts do not fit the knee as expected, or wear out earlier. In these cases, one may have to resort to total knee replacement subsequently. This happens in less than 5 % cases.