Diagnosis of Anterior Cruciate Ligament Rupture in an Emergency Department

Background: Although an early diagnosis is crucial to optimize outcomes after injury to the anterior cruciate ligament (ACL), little is known about the performance of emergency room physicians in diagnosing this injury. Hypothesis: We hypothesized that emergency room physicians would miss a substantial proportion of ACL ruptures. Study: Prospective comparative study. Methods: From April 2004 through October 2004, all patients aged 15 to 55 years and presenting at the emergency department of a teaching hospital for acute knee injury without fracture or multiple injuries were included. The results of a standardized examination conducted by the emergency physicians were compared with the findings by a sports medicine specialist 5 +/- 2 days later. Magnetic resonance imaging was performed when the specialist found a positive Lachman's test and was used as the reference standard for diagnosing ACL rupture. Cohen's kappa test was used to evaluate agreement between emergency physicians and the specialist. Results: Of the 79 included patients, 27 (34.2%) had a diagnosis of ACL rupture established by the specialist and confirmed by magnetic resonance imaging. Agreement was poor between emergency physicians and the sports medicine specialist regarding popping sound, instability, joint effusion, a positive Lachman's test, and a diagnosis of ACL rupture. Emergency physicians diagnosed only 7 of the 27 ACL ruptures. Conclusion: Emergency physicians missed a substantial proportion of acute ACL ruptures. Efforts are needed to improve their skills in diagnosing ACL rupture.