Knee Extensor Mechanism Disruptions: A Review

Abstract

Native extensor mechanism (EM) injuries are rare but disabling injuries and can present significant treatment challenges, especially in cases of chronic injury or re-rupture. The goal of this review was to provide an overview of the evaluation and management pertaining to a spectrum of extensor mechanism disruptions. Quadriceps and patellar tendon ruptures comprise less than half of EM failures and are usually amenable to predictable repair and recovery regardless of repair method. While suture anchor and cortical button fixation may be biomechanically superior, no high-level clinical evidence exits to recommend a particular method at this time. Chronic tears and re-ruptures are complex problems for which multiple novel techniques have been described, most with acceptable outcomes. No comparative studies exist to recommend a particular method. Patellar fractures are the most common EM injuries and vary in complexity. Tension band wiring, fixed angle plating and mesh plating can be used successfully depending on the fracture pattern, with plating favored as comminution increases. Important considerations include stable fixation, restoration of articular surface, re-establishment of the EM and minimal hardware prominence. In this review, we highlight pertinent anatomy, surgical indications and methods of fixation for acute and chronic injuries of the native extensor mechanism with the goal of providing a concise, thorough understanding of the subject.