Epidemiology of Existing Extensor Mechanism Pathology in Primary Anterior Cruciate Ligament Ruptures in an Active-Duty Population.

The purpose of this study is to determine the prevalence of potential graft-influencing pathologies of the extensor mechanism of the knee in patients presenting with a primary anterior cruciate ligament (ACL) rupture. We performed a retrospective review of the plain radiographs and magnetic resonance imaging (MRI) of all active-duty patients presenting with a primary ACL rupture at our institution between July 2006 and February 2009. Imaging was reviewed to determine the presence of a multipartite patella, unresolved Osgood-Schlatter's disease, and/or radiographic evidence suggestive of patella tendinopathy. A total of 197 patients were reviewed, including 27 females and 170 males. One patient (0.5%) had a bipartite patella and 4 patients (2%) had free-floating ossicles about the tibial tuberosity consistent with unresolved Osgood-Schlatter's disease. A total of 15 patients (7.6%) showed MRI evidence suggestive of patella tendinopathy. This study revealed 20 patients out of 197 (10.1%) who presented with existing extensor mechanism pathologies in radiologic studies. While preoperative imaging is routinely used to confirm clinical suspicion of ACL rupture or identify associated injuries, this study shows that it can also identify existing extensor mechanism pathologies that could ultimately influence the use of an extensor mechanism graft.