2023 ISAKOS Biennial Congress ePoster
No Single Dominant Risk Factor for Noncontact ACL Injury: Key Thresholds and Relative Contributions of Knee Geometry and Anterior-Posterior Laxity
Jacob Zeitlin, BA, New York, NY UNITED STATES
Mark Alan Fontana, PhD, New York, NY UNITED STATES
Michael Parides, PhD, New York, NY UNITED STATES
Thomas L. Wickiewicz, MD, New York, NY UNITED STATES
Andrew D. Pearle, MD, New York, NY UNITED STATES
Danyal H. Nawabi, MD, FRCS(Orth), New York, NY UNITED STATES
Bruce D. Beynnon, PhD, Burlington, VT UNITED STATES
Carl W Imhauser, PhD, New York, NY UNITED STATES
University of Vermont, Burlington, VT, UNITED STATES
FDA Status Not Applicable
Summary
There was no single dominant geometric or AP laxity risk factor for ACL injury in our cohort of young, male and female athletes; therefore, geometric and AP laxity risk factors likely act together to increase risk of noncontact ACL injury.
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Abstract
Introduction
Limited data exist regarding the association of tibiofemoral bony and soft tissue geometries and knee laxity with risk of first-time, noncontact anterior cruciate ligament (ACL) rupture. Previous work focusing on the role of knee geometry revealed that combinations of variables, which differ between females and males, are associated with risk of injury [1]. However, this work did not account for anterior-posterior (AP) knee laxity, another important risk factor for non-contact ACL injury [2]. The purpose of this study was to determine associations of tibiofemoral geometry and AP knee laxity with risk of first-time, noncontact ACL injury in high school and collegiate male and female athletes.
Methods
Over a four-year period, noncontact ACL injury events were identified as they occurred in 86 high school and collegiate athletes. Sex- and age-matched control subjects were selected from the same team. AP knee laxity was measured using a KT-2000 arthrometer. Magnetic resonance imaging was taken on ipsilateral and contralateral knees and articular geometries were measured. Sex-specific general additive models (GAMs) were implemented to investigate associations between injury risk and six biomechanical features [3]. Importance scores were calculated to rank the relative contribution of each variable.
Results
In the female cohort, the two features with the highest importance scores were lateral middle cartilage slope at 8.6% and notch width at 8.1%. In the male cohort, the two top-ranked features were AP laxity at 5.6% and lateral middle cartilage slope at 4.8%. In females, injury risk increased with lateral middle cartilage slope becoming more posterior-inferior from -6.2° to -2.0°, with a 25.5% increase in risk over this range. An increase in lateral meniscus-bone wedge angle from 27.3° to 28.2° was associated with a 17.5% decrease in risk. In males, an increase in AP displacement from 12.5 to 14.4 mm was associated with a 16.7% increase in risk.
Discussion
Of the six variables studied, there was no single dominant geometric or AP laxity risk factor for ACL injury in either the female or male cohorts. AP laxity in males was associated with sharply increased risk around 13-14 mm. Lateral meniscus-bone wedge angle in females was associated with sharply decreased risk around 28°. Geometric and laxity risk factors act cumulatively to modulate risk of noncontact ACL injury. Thresholds of AP laxity in males and lateral meniscus-bone wedge angle in females associated with elevated injury risk could provide targets to guide both surgical and conservative treatments to reduce risk of ACL injury.
REFERENCES: [1] Sturnick. AJSM 2015. [2] Uhorchak. AJSM 2003. [3] Lou. SIGKDD 2013.