Dr. Masonis and colleagues from Ortho Carolina presented a poster at the 25th annual meeting of the American Association of Hip and Knee Surgeons in November 2015. They reviewed the outcomes of 174 patient who underwent either unicompartmental or total knee replacement. They found that a mean followup of approximately 10 years, the revision rate for the partial knee replacement was significantly higher. It is 16.5% versus 6.9% for total knee replacement. The partial knee replacement occurred earlier at an average of 33 months postop. The most common failure mode for partial knee replacement was loosening in 53% and progression of arthritis in other compartments in 23%. The most common failure mode for total knee replacement was aseptic loosening or infection. They found no difference between total knee replacement and partial knee replacement with regard to patient reported outcome measures at an average of 9.3 years. The 10-year survivorship was significantly lower for a partial knee replacement at 84% versus 93% for total knee replacement.
There is a definite indication for partial knee replacement in the appropriately selected individual, but this averages approximately 5% of all patients who are indicated for knee replacement procedures.
A 2nd poster was presented at the same meeting by Dr. Lee and coauthors from Orange County, California. They reviewed a group of patients all less than 60 years old with minimum 5-year followup of either a partial or unicompartmental knee replacement (49 knees) or a total knee replacement (91 knees). They found that all patients improved with regard to various clinical ratings. There was a higher occurrence of adverse events in the partial knee replacement group and revision for the partial knee replacement group were greater at 13.7% versus 3.3% for the total knee group. They concluded that young patients undergoing either a partial knee replacement or appropriately done total knee replacement showed no differences with regard to pain relief and function, however, there was a significantly higher revision rate for the partial knee replacement in these patients.