Analysis and Treatment of Complications after Unicompartmental Knee Arthroplasty

PURPOSE To analyze the causes and types of complications after unicompartmental knee arthroplasty (UKA) and determine proper prevention and treatment methods. MATERIALS AND METHODS A total of 1,576 UKAs were performed for osteoarthritis of the knee from January 2002 to December 2014 at one institution. We analyzed complications after UKA retrospectively and investigated proper methods of treatment. RESULTS A total of 89 complications (5.6%) occurred after UKA. Regarding the type of complications after UKA, there were 42 cases of dislocation of the mobile bearing, 23 cases of loosening of the prosthesis, 6 cases of periprosthetic fracture, 3 cases of polyethylene wear, 3 cases of progression of arthritis in the contralateral compartment, 2 cases of medial collateral ligament injury, 2 cases of impingement, 5 cases of infection, 1 case of arthrofibrosis, and 2 cases of failure due to unexplained pain. The most common complication after UKA was mobile bearing dislocation in the mobile-bearing knees and loosening of the prosthesis in the fixed-bearing knees, but polyethylene wear and progression of arthritis were relatively rare. The complications were treated with conversion to total knee arthroplasty in 58 cases and simple bearing change in 21 cases. CONCLUSIONS The most common complication after UKA was dislocation of the mobile bearing. When a complication occurs after UKA, appropriate treatment should be performed after accurate analysis of the cause of complication.