Association of Noncontact Anterior Cruciate Ligament Injury With Presence and Thickness of a Bony Ridge on the Anteromedial Aspect of the Femoral Intercondylar Notch

Abstract

The presence and thickness of an anteromedial bone ridge in the femoral notch has been identified as a potential risk factor for noncontact anterior cruciate ligament injury. A biomechanical injury model involving the femoral notch ridge in anterior cruciate ligament tears is proposed in which the anterior cruciate ligament may be tented and stretched over the anteromedial notch ridge during knee valgus and internal tibial rotation; alternatively, the anterior cruciate ligament may be impinged at the lateral anterior outlet wall during knee valgus and external tibial rotation. Further investigation to determine the origin of the bone ridges and the validity of the proposed injury model is recommended.

ACL Research Retreat VII: An Update on Anterior Cruciate Ligament Injury Risk Factor Identification, Screening, and Prevention

“…The majority of prospective and retrospective case-control studies comparing ACL-injured patients with uninjured controls indicate that ACL-injured patients have smaller ACLs (in area and volume), 94,95 greater lateral posterior-inferior tibial plateau slopes (but not necessarily medial tibial slopes), [96][97][98][99][100] and smaller femoral notch widths and notch width indexes. 95,98,[101][102][103][104][105][106][107][108] The presence of a more prominent or thicker bony ridge on the anteromedial outlet of the femoral intercondylar notch has also been reported in ACL-injured patients versus controls. [95][96][97][98] In addition, reduced condylar depth of the medial tibial plateau may be characteristic of ACL injury.…”

“…95,98,[101][102][103][104][105][106][107][108] The presence of a more prominent or thicker bony ridge on the anteromedial outlet of the femoral intercondylar notch has also been reported in ACL-injured patients versus controls. [95][96][97][98] In addition, reduced condylar depth of the medial tibial plateau may be characteristic of ACL injury. 96,97,100 Coronal slope has not been associated with ACL injury risk.…”

“…97,100 Multivariate analyses suggest that smaller ACL volume and femoral notch width at the inlet and outlet and greater anteromedial bony ridge thickness and posterior-inferior directed slope of the lateral tibial compartment may independently contribute to injury risk and together provide more information on injury risk potential. 95,98,109,110 However, because the geometric variables examined have differed, there is no clear consensus as to the unique combination of these variables that most strongly predicts ACL injury risk in males and females.…”

“…111 Sex differences in knee structural anatomy may also explain why associations of these variables with ACL injury history are somewhat different between males and females. 95,98,110 Biomechanically, good evidence indicates that knee-joint geometry is related to higher-risk biomechanics. Greater posterior-inferior lateral tibial slopes are associated with greater anterior joint reaction forces, 116 anterior translation of the tibia relative to the femur, 117,118 and peak anterior tibial acceleration 119 ; when combined with a smaller ACL cross-sectional area, these factors are associated with greater peak ACL strains.…”

ACL Research Retreat V: An Update on ACL Injury Risk and Prevention, March 25–27, 2010, Greensboro, NC

“…45 6. Clear laxity differences have been observed between males and females, with females often displaying greater genu recurvatum, 46,47 anterior knee laxity, [48][49][50][51][52] and general joint laxity.…”