Open reduction and polyaxial plating for stemmed knee periprosthetic fractures: A case series

Introduction: Stemmed total knee arthroplasty (STKA) periprosthetic fractures (PPFs) are an emerging problem affecting frail patients. Their surgical fixation is challenging, due to intramedullary involvement and poor bone stock. Polyaxial locking plating has yielded good results in implant-related femur fractures. We hypothesized that this treatment would provide similar results for STKA PPFs. Methods: Retrospective analysis of consecutive patients with a femoral PPF or inter-implant fracture around a knee revision stem who had undergone open reduction and periprosthetic-specific polyaxial plate fixation. Results: We found 14 cases of mean age 85.4 years. Cerclages were used in 80% of cases. Fixation of a mean 8.6 cortices around the revision stem was achieved, with an overall screw density of 1:2 or 1:3. Four patients lost their ability to walk, while four experienced postoperative local complications. Bone healing was achieved in all except one who died during hospitalization. The 13 remaining survived the first year of follow-up. Conclusion: STKA PPFs are an emerging and challenging problem affecting frail patients. Treatment using polyaxial locking plates provides stable fixation allowing early mobilization despite high complication rates.