Uni or Partial Knee replacement guide

Much has been written about total knee replacement, but little on partial or half knee or unicondylar knee replacement. A total knee replacement is a very successful operation for a person whose entire knee is affected by osteoarthritis. A half knee replacement resurfaces only the affected half or condyle.  In a small proportion of osteoarthritis patients the entire knee is not affected to start with and only one out of three compartments in the knee is affected. To understand what a unicondylar knee replacement means is, you will need to understand the anatomy of the knee joint. The knee joint actually contains three compartments, the inner half, the outer half and the knee cap or the front. In many middle aged patients the Fig shows bone from inner half removed during a partial knee replacement arthritis process starts in the inner half of the knee joint. It therefore makes sense to replace only this portion alone. Each one or a combination of two can be replaced. For e.g.: one could do a medial or inner half partial knee replacement, or outer half replacement or just replace the patello-femoral joint alone. The surgeon verifies that the other two compartments are normal or there is  only minor damage before proceeding with  a unicondylar half knee replacement. Commonly a medial unicondylar knee replacement is done. In this operation the inner half alone is replaced with prosthesis. To be eligible for a partial knee, the patient should fulfill three criteria, a) The inner half alone should be affected b) The ACL should be intact c) The deformity should be mild not exceeding 15 degrees of varus. Two groups of patients may require a Unicondylar knee 1) A patient in their fifties with partial arthritis in whom a total knee replacement may be required after ten to fifteen years 2) A patient in the eighties for whom this is the only operation that will be required. The advantages of a partial or half knee replacement are 1) Less morbidity. The operation can be done through small incisions as long as only three inches 3 inch scars       2) Less blood loss occurs as healthy bone and cartilage is not damaged during the surgery. 3) The range of movement is almost like a normal knee. Fig shows small sized incisions for a partial 4) Quicker recovery as there is less post operative pain due to the small incision 5) Knee feels more normal as the ligaments are preserved. Prosthesis used at my centre Oxford knee ( Biomet)- This is a mobile bearing partial knee. It resurfaces the inner half commonly and the outer half less commonly. The oxford knee replacement operation is done through a minimally invasive surgical approach as shown in the figure above. Bilateral Oxford knee replacements are done routinely at our centre. This allows the patient to recover faster. Repicci knee ( Biomet) Allegra knee( Zimmer) Bilateral Oxford knees Watch  video of Patient with bilateral partial knee replacement