Femoral Notch Morphology and Its Association with Anterior Cruciate Ligament Injury: An MRI Study

Abstract

Introduction: The anterior cruciate ligament is a critical stabilizer of the knee joint, and its injury is associated with significant morbidity. This study evaluated the association between the femoral intercondylar notch morphology and anterior cruciate ligament injury on MRI of the knee joint.
Methods: This retrospective case-control quantitative study included 112 patients, comprising 56 cases with complete anterior cruciate ligament injuries and 56 controls with normal anterior cruciate ligaments. Measurements of femoral notch shape, notch width, notch width index, notch angle, and alpha angle were done on MRI images, and their association with anterior cruciate ligament injury was analyzed. Statistical analysis included chi-square and independent sample t-tests, and a p-value of < 0.05 was considered significant.
Results: Type A notches were significantly associated with anterior cruciate ligament injuries, with 67.5% of type A notch shapes having injury compared to 40.2% in non-A notch shapes (p = 0.006). Anterior cruciate ligament-injured patients had narrower mean notch widths (2.01 ± 0.20 cm vs. 2.14 ± 0.22 cm, p = 0.001) and lower notch width indexes (0.27 ± 0.02 vs. 0.29 ± 0.02, p=0.000) when compared to normal anterior cruciate ligaments. Anterior cruciate ligament injury was seen in 73% of patients with notch stenosis. The mean notch angle was significantly lower in anterior cruciate ligament-injured individuals (52.03° ± 6.05° vs. 54.72° ± 6.69°, p=0.028), while the alpha angle showed no significant differences.
Conclusions: Narrow notch width, lower notch width index, and notch angle, and type A notch shape are associated with ACL injuries.