Management of tibial post fractures in posterior stabilized total knee arthroplasties: Case series and review of literature

Background: Highly Crosslinked Polyethylene was introduced to decrease plastic wear and subsequent osteolysis. However, this was at the expense of the mechanical properties of the polyethylene slightly reducing its overall physical strength. Fracture of the polyethylene tibial post is a rare but catastrophic complication in posterior-stabilized (PS) total knee arthroplasty (TKA). Aim of the study: We report 4 cases of fractured tibial post in a posterior stabilized total knee with highly Crosslinked Polyethylene. Clinical presentations, intraoperative findings, and failure mechanisms are evaluated, alongside a systematic literature review. Methods: Between May 2019 and September 2024, four cases with fractured tibial posts were presented and managed at our institution. Clinical records, pre- and postoperative radiographs, failure timeframes, and surgical intervention were retrospectively reviewed. Results: Patients predominantly presented with unexplained acute onset of instability and effusion in a previously well-functioning total knee arthroplasty. Mean time from the primary knee replacement procedure to the onset of symptoms was 11.25 years (range 9–14). Revision surgery was successfully performed in all four cases ranging from isolated liner exchange to full components revision with a constrained non hinged prosthesis. Conclusions: Tibial post fracture should be strongly suspected in patients with late instability following PS TKA. Surgeons should be aware of this rare complication. The regular use of highly crosslinked polyethylene in Posterior stabilized total knee arthroplasty is not advisable, with a better shift to stronger and newer types of plastic.