Magnetic Resonance Imaging Analysis of Morphological Parameters in Anterior Cruciate Ligament Injury

Abstract

Introduction: Factors associated with Anterior Cruciate Ligament (ACL) injury are multiple. Among the anatomical factors, intercondylar notch width and alpha angle are also implicated as a cause for ACL injury. Magnetic Resonance Imaging (MRI) of the knee joint is helpful in identifying the ACL injury and factors predisposing it. Aim: To study the alpha angle and intercondylar notch width, analysed by MRI among ACL injured cases and compare with that of controls. Materials and Methods: In this retrospective study, MRI knee of 450 patients (18-60 years, 296 males, 154 females) were evaluated for ACL injury and were grouped under cases (torn ACL) and controls (intact ACL) with 225 participants in each group. Continuous variables were expressed as the mean±Standard Deviation (SD). Means of normal variables were compared using student’s t-test and means of non parametric variables using Mann-Whitney U test. Comparison of counts and percentages was carried out using the Chi-square (χ2) test. Results: There was no significant difference in alpha angle between males and females. Highly significant difference in intercondylar notch width was seen between males and females (22.46±2.54 mm vs 21.61±2.48 mm, p-value=0.002). Males had higher ACL injury compared to females. The mean alpha angle was higher in patients with a torn ACL than in those with an intact one (51.88±3.72 vs 50.57±3.46, p<0.001). In torn group intercondylar notch width was lower than intact group and this difference was significant (21.18±2.67 mm vs 23.16±1.99 mm, p<0.001). Conclusion: Study results revealed that the ACL tears were associated with high alpha angle and narrow intercondylar notch width. ACL tears occur more frequently in men than in women and also most commonly involves age group between 31-40 years.