Traumatic Fracture of the Polyethylene Tibial Post in a Posterior-Stabilized Total Knee Arthroplasty: A Case Report

Posterior-stabilized total knee arthroplasty (TKA) uses a cam-post mechanism to provide anteroposterior stability, but polyethylene tibial post failure can occur as a rare yet serious complication. We report a case of early TKA failure caused by traumatic tibial post fracture. A patient who underwent primary posterior-stabilized total knee arthroplasty (TKA) in March 2023 sustained a fall 6 months postoperatively and experienced progressive knee pain and functional deterioration. Clinical and radiographic assessments demonstrated fracture of the polyethylene tibial post, resulting in knee instability and recurvatum. Revision TKA using a rotating-hinge prosthesis was performed in February 2025. Recurvatum was corrected, and knee stability and function improved. This case underlines that tibial post fracture is an uncommon but serious failure mode after posterior-stabilized TKA. For patients with severe knee deformity and ligamentous insufficiency, a rotating hinge prosthesis may be a viable option for restoring stability and function.