Trunnion Failure in Revision Total Knee Arthroplasty.

In revision total knee arthroplasty, joint kinematics must be maintained amid bone and ligamentous insufficiency. Current modular designs address defects while allowing for intraoperative prosthesis customization through a variety of stem extensions and constraints. Additional constraint improves knee stability while increasing stress at the implant-host interface and modular junction of the implant. This renders the prosthetic stem-condyle junction more prone to fatigue failure. We report 2 cases of prosthetic stem-condyle junction failure in in a varus-valgus constrained revision total knee arthroplasty.