Association between knee morphometric parameters and non-contact anterior cruciate ligament rupture in professional male football players: a case-control MRI study

Morphological characteristics of the knee have been widely investigated as potential risk factors for anterior cruciate ligament (ACL) injury; however, the findings remain controversial. Most previous studies have evaluated heterogeneous populations with varying levels of physical activity. The aim of this study was to investigate the association between knee morphometric parameters and non-contact ACL rupture in a sport-specific population of professional male football players. Clinical and radiological data of professional football players evaluated between 2020 and 2025 were retrospectively analysed. Athletes with non-contact ACL rupture confirmed by clinical examination and magnetic resonance imaging (MRI) were included in the ACL rupture group, whereas athletes with normal clinical and MRI findings were included in the control group. Lateral tibial slope (LTS), medial tibial slope (MTS), global tibiofemoral rotation angle (TFRA), notch outlet length (NOL), tibial spine width (TSW), and notch width index (NWI) were measured on MRI. A total of 81 professional male football players were included, consisting of 40 athletes with ACL rupture and 41 controls. The mean ages of the patient and control groups were 23.65 ± 5.41 and 23.68 ± 4.95 years, respectively (p = 0.857). No statistically significant differences were observed between groups in terms of tibial slope measurements, tibiofemoral rotation angle, notch outlet length, or tibial spine width (p > 0.05). However, the NWI was significantly lower in the ACL rupture group, with a mean between-group difference of 1.38 percentage points (95% CI, 0.57-2.18; p = 0.001), and was approximately equal to the estimated minimal detectable change (MDC95 = 1.48). In multivariable analysis, a lower NWI remained associated with ACL rupture (adjusted OR = 0.677; 95% CI, 0.519-0.883; p = 0.004), and ROC analysis showed moderate discrimination (AUC = 0.700, 95% CI, 0.584-0.810). A relatively smaller intercondylar NWI was associated with non-contact ACL rupture in professional male football players. However, this finding should be interpreted as a population-level association rather than evidence of causality or individual predictive value. The other evaluated knee morphometric parameters were not significantly associated with ACL rupture in this sport-specific population.