Case ReportEarly Nontraumatic Fracture of the Polyethylene Tibial Post in a NexGen LPS-Flex Posterior Stabilized Knee Prosthesis
Section snippets
Case Report
A 63-year-old man (height, 167 cm; body mass index, 27.8) with a history of cerebral infarction, which resulted in left-sided hemiparesis and circumducting gait at the age of 56 years, presented with left knee instability. Three years before this presentation, he had undergone left TKA with a NexGen LPS-Flex TKA.
The index primary knee arthroplasty had been performed for the treatment of an advanced left arthritic knee. A standard midline incision with midvastus arthrotomy was used to implant a
Discussion
Posterior stabilized total knee prostheses often lead to magnificent clinical results. The cam-and-post mechanism reproduces the physiologic femoral rollback during knee flexion. Moreover, the femoral cam and tibial polyethylene post can act as a mechanical stop to limit posterior displacement of the tibia relative to the femur. However, it has to be noted that the failure of this mechanism always leads to abnormal knee kinematics and instability 1, 2, 3, 4, 5. Anterior and posterior tibial
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Cited by (32)
Catastrophic Failures of the Tibial Post in a Bicruciate Substituting Total Knee Prosthesis
2021, Arthroplasty TodayCitation Excerpt :Few cases of tibial post breakage in PS TKA have previously been reported. To our knowledge, 5 previous cases have been reported in the NexGen prosthesis (Zimmer, Warsaw, IN) [4,19–24]. Chiu et al. described a case of atraumatic tibial post fracture 3 years after TKA [19].
Posterior stabilized designs in modern total knee arthroplasty: Vestigial organs
2018, Seminars in Arthroplasty JSESCitation Excerpt :The cam and post mechanism is also a potential source of polyethylene wear and fatigue failure, being a mechanical articulation under stress. Breakage via fatigue failure of this mechanism has been observed (Fig. 1) and reported in multiple PS bearing designs [3, 4]. Dislocation also may occur in PS design knees, usually posteriorly but occasionally anteriorly [5].
No benefits or funds were received in support of the study.