Detection of Multiple Tibial Malalignment-Induced Early Polyethylene Breakage Using Single Plane Fluoroscopy: A Case Report.

Case: A 75-year-old woman underwent cruciate retaining total knee arthroplasty (TKA) for osteonecrosis of the knee, converted from unicompartmental arthroplasty due to an intraoperative medial tibial plateau fracture. Four years later, she experienced persistent knee pain. Computed tomography revealed tibial malalignments in 2 planes. In vivo kinematic analysis using single-plane fluoroscopy, which can visualize the femorotibial contact, indicated varus thrust with lateral subluxation of the tibial component and the femoral component recessing into the polyethylene insert. Revision TKA affirmed the polyethylene insert breakage.

Conclusion: Malalignment might have caused mechanical failure, and in vivo kinematic analysis was useful to visualize abnormal kinematics in TKA.