Periprosthetic Fracture following Partial Knee Arthroplasty

Partial knee arthroplasty is a procedure with long-term successful outcomes. However, there are several potential complications including retained cement fragments, bearing dislocation, infection, component loosening, medial collateral ligament injury, and overcorrection, leading to progressive arthritis. Periprosthetic fracture is an uncommon complication, with multiple reports showing an incidence of less than 1%. Hence, there are no established algorithms to guide treatment. A consecutive series of 2,464 patients who underwent partial knee arthroplasty between January 2009 and April 2017 was reviewed. We identified 16 patients with early periprosthetic fracture, with an incidence of 0.6%. All of these were tibial fractures, which occurred at a mean of 35 days postoperatively. There were 5 males and 11 females, with an average age of 70 years at the time of surgery. Average follow-up was 62 months. Two patients had contralateral compartment insufficiency fractures that were successfully treated nonoperatively, five patients immediately underwent total knee arthroplasty (TKA), and nine patients underwent open reduction internal fixation (ORIF). Two of these cases had a failed ORIF and required conversion to TKA. Seven patients were successfully treated with a medial buttress plate in compression. Average Knee Society Score at final follow-up was 81, and average flexion was 115 degrees, with no patients having greater than 5-degree flexion contracture. Periprosthetic fracture following partial knee arthroplasty resulted in a high rate of conversion TKA. However, ORIF in select patients resulted in fracture healing and retention of the partial knee replacement. All patients were successfully treated with low complication rates, excellent range of motion, and acceptable knee scores at final follow-up.