Management of periprosthetic patellar fractures. A systematic review of literature.

Despite advances in surgical technique and implant design, complications involving the extensor mechanism and patellofemoral joint after total knee arthroplasty (TKA) continue to be the most common cause of pain and the most commonly cited reason for revision surgery. Periprosthetic patellar fractures occur in 1.19% of all reported cases after TKA, with a clear correlation with resurfacing of the patella. In 88.32% of the cases reported the fracture is not associated with a traumatic event and it is identified at the follow-up examination during the first 2 years after knee replacement. Predisposing factors for fracture include lateral release, excessive bone removal, peg fixation and cementation, improper patellar tracking and prosthesis malpositioning. More than 50% of fractures are associated with a loose implant which complicates the fracture management. Non-operative treatment seems to offer acceptable functional results and pain relief, especially in cases of minimal displacement and stable implant fixation. However, when surgical reconstruction is undertaken, open reduction and internal fixation with tension band or cerclage wiring should not be the first choice of treatment as the rate of failure and subsequent non-union may be as high as 90%.