A radiographic analysis of the relationship between the size and shape of the intercondylar notch and anterior cruciate ligament injury

Abstract

Notch-view radiographs were obtained from 108 persons with anterior cruciate ligament (ACL) injuries (55 women, 53 men) and 186 with intact ACL (94 women, 92 men). Notch width, femur width, and notch width index were determined from each of the 294 radiographs. The notch was also categorized as either A-shaped or non-A-shaped. Intrarater and interrater reliability ranged from 0.82 to 0.99 for notch width and femur width, respectively. Reliability within and between raters for the classification of notch shape ranged from 0.80 to 1.0. Notch width was significantly influenced by a 10 degree change in knee angle when repeated radiographs were taken. Femur width was not affected by knee angle across this range. Analysis revealed a higher proportion of A-shaped notches among women than men. However, notch shape was not related to injury status. Results showed a smaller notch width and notch width index in ACL-injured patients regardless of notch shape or gender. A-shaped notches were smaller than non-A-shaped notches regardless of injury status or gender. Both notch width and notch width index were found to be significant indicators of ACL injury. Knowledge of the shape of the notch added no useful information in differentiating patients based on injury status. Thus, regardless of gender, individuals who possess smaller notch dimensions appear to be at greater risk of injury than individuals with larger notches.

Risk factors for Anterior Cruciate Ligament injury in skeletally immature patients: analysis of intercondylar notch width using Magnetic Resonance Imaging

“…Our finding that a lower NWI index may predispose to ACL injury in the paediatric population is in accordance with previous studies looking at young adult populations [2][3][4][5][6][7]20]. While there is still disagreement in the literature as to whether variations in notch geometry related to differences in gender or limb dominance, play a contributing role in ACL injuries, we did not find a difference in NWI with respect to gender, involved side, mechanism of injury or type of sport engaged in at the time of injury [7,12,13,18,21,22].…”

“…This difference may be caused by different imaging techniques used for the evaluation of NWI. Two studies measuring NWI using MRI [8,21] have shown much higher values for normal adult populations than values reported in radiographic studies [2][3][4][5][6][7]20].…”

Gender differences in passive knee biomechanical properties in tibial rotation

“…43 Ireland and colleagues reported that females have a higher proportion of A-shaped notches and both notch width and notch width index were found to be significant indicators of ACL injuries. 11 They suggested that regardless of gender, individuals with smaller notch dimensions are at greater risk of ACL injury than those with larger notches. 11 Finally, in vivo studies on joint laxity during anterior translation and internal rotation showed increased joint laxity in females when compared to males.…”

“…11 They suggested that regardless of gender, individuals with smaller notch dimensions are at greater risk of ACL injury than those with larger notches. 11 Finally, in vivo studies on joint laxity during anterior translation and internal rotation showed increased joint laxity in females when compared to males. 19,23,24 The results from our study add that increased knee joint laxity in females occurs with external tibial rotation as well.…”

“…4 Despite the clinical significance, factors contributing to the higher incidence remain unclear. Proposed causes include women having a larger Q-angle, [5][6][7] wider pelvis, 8,9 narrower intercondylar notch, [10][11][12] different hormonal status, [13][14][15] different patterns of muscle activity during jumping, landing, and pivoting, [16][17][18] larger knee joint laxity, [19][20][21][22][23][24] and higher likelihood of ACL impingement against the intercondylar notch. 25,26 Considering that the highest injury incidence is in individuals 15 to 25 years old who participate in pivoting sports, 1 knee biomechanical properties in internal and external tibial rotation may play an important role.…”