Complete tibial post wear with neglected dislocation after posterior stabilized total knee arthroplasty - A case report

Chung-Ting Liu ； Yi-Chih Chen ； Yung-Chang Lu ； Chang-hung Huang

《Formosan Journal of Musculoskeletal Disorders》 8卷4期 (2017/11) Pp. 187-192

https://doi.org/10.6492/FJMD.20160809

摘要

Failure of the tibial post is an uncommon but disabling complication after posterior stabilized (PS) total knee arthroplasty (TKA). Sustained instability of the knee joint after post failure may result in knee dislocation. Herein, we present a case of neglected dislocation between the femoral and tibial components of TKA after complete tibial post wear. Revision surgery with legacy constrained condylar knee (LCCK) components was performed, and all retrieved components were sent to our laboratory for analysis. Scanning electron micrographs (SEM) were also taken over the base of the tibial post. Multiple stepped wear lines were found parallel to the anterior edge, indicating progressive wear of the polyethylene post. Much irregular laminating tear was also found, which may have been due to repeated trauma from the instability. The flexion position of the femoral component in this case caused anterior impingement of the post, and frequent deep flexion of the knee joint then caused posterior wear of it, ultimately resulting in post failure. Surgeons should be aware of the potential for such problems at the cam-post interface.

關鍵字

TKA ； knee dislocation ； post fracture