Partial knee replacement – Medial Uni

This is an xray of a partial knee replacement. Specifically, this is a medial unicompartmental knee replacement. This fifty something year old man had pain localized to the medial aspect of his right and left knees. Carefully look at this xray and note that the lateral compartments (outside of each knee) has a well maintained joint space while the medial compartment of the untreated knee has bone on bone. The treated knee has a femoral component cemented into the femur(thigh bone), a tibial component cemented to the tibia (shin bone), and a ultra high molecular weight polyethylene component (xray invisible space) which is locked into the tibial tray. This procedure has provided the patient complete relief of his symptoms of knee arthritis. He went on to have his left knee partially replaced in the exact same manner and now functions normally without knee pain. He has returned to work and feels good. He was hospitalized only overnight in the hospital and was riding an exercycle within 10 days after surgery.

Unicompartmental Knee Replacement Has Advantages Over Total Knee Replacement

Unicompartmental knee replacement (e.g. Makoplasty partial knee replacement) offers a number of advantages over TKR including reduced risk of complications, bone and ligament preservation, and a more naturally feeling knee.  One study looking at 14,000 knee joint replacement patients found the partial knee patients (compared to TKR patients) were more likely to achieve an excellent result and more likley to be highly satisfied and were less likely to have had a complication or hospital readmission.

Unicompartmental Knee Replacement : A Twenty Year Outcome Study

A study from France published by Jean-Noel Argenson, MD demonstrated impressive implant survival with good function for unicompartmental knees years after the initial surgery.  Implant “survival” rate was calculated to be 83 % at 15 years after surgery and 74 % at 20 years after surgery.  Age of the surviving patients was 52 – 90 years (some patients had received the partial knee replacements while in their 30’s).

Medial Makoplasty – Unicompartmental knee

Unicompartmental knee replacement is a less invasive alternative resulting in a more natural feeling knee compared to Total knee replacement in properly selected patients.  This studies supports the belief that long term knee function and long term pain relief is predictably attainable with unicompartmental (partial) knee replacement.  Improved precision in surgical technique available today using robotic surgical technique (Makoplasty) will likely lead to even better long term outcomes for today’s patients.

Partial Knee Replacement for Unicompartmental Knee Arthritis on the Rise

Doctors and Patients continue to seek treatment options that spare normal knee tissue and is less invasive to their body. Partial Knee Replacement (unicompartmental knee replacement) is an example of this principle.

In one select data base, from 1998 to 2005 the number of Partial Knee Replacements increased from 6570 to 44,990 procedures – a 32 % increase. In the same time period Total Knee Replacement increased by 9 %.

At this same time studies have shown Unicompartmental Knee Replacement surgery is > 90 % successful at five years and another study shows 85 % implant survival at ten years.

Partial knee replacement of any one of the three knee compartments preserves all the knee ligaments, can be done with minimally invasive techniques, feels more transparent, is less painful and results in a faster recovery compared to Total Knee Replacement. The age range for unicompartmental surgery is typically between 40-70 years of age.

New techniques for partial knee replacement are evolving and one would expect that in the future more patients will opt to have a partial rather than a total knee replacement.