Fractured polyethylene tibial post in a posterior-stabilized knee prosthesis presenting as a floating palpable mass

Complications associated with posterior-stabilized total knee arthroplasty (TKA) include patellar clunk syndrome, posterior subluxation of the tibial component, tibial post wear, and tibial post failure. Recently, an increasing number of reports have been issued on polyethylene tibial post failure in posterior-stabilized TKA. In most of these cases, tibial post failure in a well-functioning posterior-stabilized TKA was suspected based on clinical symptoms, such as a sudden onset of pain, effusion, patellar clunking, knee instability, and prosthesis dislocation. However, a floating, palpable, hard, mass-like symptom in the knee joint has not been previously reported. The authors report a case of a fractured polyethylene tibial post in a posterior-stabilized TKA that manifested as a palpable mass in the suprapatellar pouch.