The posterior lateral femoral contusion sign (Aamer botchu sign): An ancillary sign of MCL injury

Abstract

Medial collateral ligament complex (MCL) injury is the commonest injury in the knee. Assessment of the osseous edema pattern can help predict the mechanism of a soft tissue injury. Material and methods. We performed a retrospective study to analyse the osseous edema involving the lateral femoral condyle and associated soft tissue injuries. Results. Of the 334 patients with radiological diagnosis of MCL sprain, there were 53 patients with a clinical history of valgus stress injury and bone bruising of the lateral femoral condyle. These patients were divided into two cohorts depending in the presence of isolated MCL injury (cohort one) or co-existing MCL and ACL injuries (cohort two). There were 23 patients in cohort one; mean age was 38 years (range 16-68) with 15 males and 8 females. In cohort two, there were 30 patients; mean age was 30.5 years (range 14-62) with 20 males and 10 females. Assessment of the location of bone bruising within the lateral femoral condyle revealed bone bruising involving the posterior third in 19/23 cases in cohort one compared to 1/30 patients in cohort 2 which was statistically significant (p<0.001). These were high grade 2 or grade 3 sprain involving the superficial and deep components of the MCL, posterior oblique ligament and medial patellofemoral reti-naculum. Conclusion. Based on our results with conclude that isolated osseous edema of the posterior third of the lateral femoral condyle is associated with isolated MCL injury. (Aamer Botchu sign).