Conversion Knee Arthroplasty Using a Rotating Hinge as a Salvage Prosthesis Following Periprosthetic Joint Infection and Ligamentous Insufficiency: A Case Report

BackgroundIn the event of a complex revision TKA in which there is extensor mechanism involvement and ligamentous instability or insufficiency, non-linked levels of constraint may not be adequate for achieving restoration of patient function. Total knee arthroplasty devices that incorporate a linked level of constraint are successful alternatives to unlinked devices (PS and PS-Constrained) in this clinical context.Case PresentationWe present the case of a 62 year-old male patient that required a non-articulating knee fusion and multiple total knee arthroplasty revisions in conjunction with a ruptured and repaired extensor mechanism, ligamentous instability, bone loss and periprosthetic joint infection.  (Revision knee prosthesis that includes a increasing degree of nodularity and physical constraint).  The subsequent risk factors associated with the loss of bone and ligamentous insufficiency required performing conversion arthroplasty with a knee prosthesis that includes an increasing degree of modularity and physical constraint not commonly used in revision total knee arthroplasty.DiscussionThe authors report on a patient who underwent multiple operative procedures, we outline the step wise decision making progression that lead to the successful eradication of the PJI and reimplant device strategy based on the confounding factors presented.  We assess the use of revision TKA systems that offer extreme degrees of constraint which should be considered in complex revision knee revision procedures.