Taner ALIÇ, Yunus Erol ŞAHİNCİ, Soner GÜREL
Journal of Experimental and Clinical Medicine - 2026;43(2):252-256
Tibial post fracture in mobile-bearing posterior-stabilized total knee arthroplasty (MB-PS TKA) is a rare but clinically significant complication associated with knee instability. A 72-year-old female presented with progressive knee pain and instability eight years after primary MB-PS TKA. Radiographic and clinical evaluation demonstrated varus malalignment and excessive posterior tibial slope. Revision TKA was performed, and intraoperative findings confirmed a fractured polyethylene tibial post with localized wear. Excessive posterior tibial slope may lead to anterior tibial translation and increased cam-post impingement, while varus malalignment results in asymmetric load distribution and accelerated polyethylene wear. Although mobile-bearing designs are intended to reduce stress concentration, these advantages may be negated under conditions of malalignment. Patient-related factors such as elevated body mass index and sustained physical activity may further contribute to implant failure. Proper component alignment and patient-specific risk assessment are essential to prevent tibial post fracture in MB-PS TKA. Clinicians should consider polyethylene-related complications in patients presenting with late instability, even in the absence of a clearly defined traumatic event.
