Sex-dimorphic landing mechanics and their role within the noncontact ACL injury mechanism: evidence, limitations and directions

Abstract

Anterior cruciate ligament (ACL) injuries continue to present in epidemic-like proportions, carrying significant short- and longer-term debilitative effects. With females suffering these injuries at a higher rate than males, an abundance of research focuses on delineating the sex-specific nature of the underlying injury mechanism. Examinations of sex-dimorphic lower-limb landing mechanics are common since such factors are readily screenable and modifiable. The purpose of this paper was to critically review the published literature that currently exists in this area to gain greater insight into the aetiology of ACL injuries in females and males. Using strict search criteria, 31 articles investigating sex-based differences in explicit knee and/or hip landing biomechanical variables exhibited during vertical landings were selected and subsequently examined. Study outcomes did not support the generally accepted view that significant sex-based differences exist in lower-limb landing mechanics. In fact, a lack of agreement was evident in the literature for the majority of variables examined, with no sex differences evident when consensus was reached. The one exception was that women were typically found to land with greater peak knee abduction angles than males. Considering knee abduction increases ACL loading and prospectively predicts female ACL injury risk, its contribution to sex-specific injury mechanisms and resultant injury rates seems plausible. As for the lack of consensus observed for most variables, it may arise from study-based variations in test populations and landing tasks, in conjunction with the limited ability to accurately measure lower-limb mechanics via standard motion capture methods. Regardless, laboratory-based comparisons of male and female landing mechanics do not appear sufficient to elucidate causes of injury and their potential sex-specificity. Sex-specific in vivo joint mechanical data, if collected accurately, may be more beneficial when used to drive models (e.g., cadaveric and computational) that can additionally quantify the resultant ACL load response. Without these steps, sex-dimorphic landing mechanics data will play a limited role in identifying the aetiology of ACL injuries in women and men.

Comparison of Strength and Endurance between Open and Closed Kinematic Chain Exercises after Anterior Cruciate Ligament Reconstruction: Randomized Control Trial

“…An ACL injury typically occurs during the landing portion of a jump in ordinary sports activities and has a greater incidence in women than in men 1,2) . ACL deficiency may lead to degenerative changes such as tears of the meniscus.…”

The Impact of Sex and Knee Injury History on Jump-Landing Patterns in Collegiate Athletes

“…This supports the use of the LESS as a helpful clinical screening tool because it is able to identify similar sex differences that have been reported in laboratory-based investigations using 3-dimension kinematic instrumentation. 28 To our knowledge, our study is the only investigation to report sex differences in LESS item scores for individuals in the traditional college athletic setting. Previously, Beutler et al 20 compared sex differences across LESS item scores in incoming military cadets and reported that females generally demonstrated poorer jump-landing patterns than their male counterparts.…”

“…The investigators reported that there were discrepancies and a lack of consensus between studies for sagittal (eg, knee flexion, hip flexion) and transverse (eg, knee rotation, hip rotation) plane sex differences, but good agreement between studies reporting frontal plane sex differences, particularly for peak knee valgus angle. 28 Furthermore, when considering studies that used similar jump-landing task parameters as the LESS (ie, 30-cm jump-landing height, double-legged landing), the majority of studies reported that females displayed more knee valgus angle at initial ground contact 29,30 and at peak knee valgus angle 29-33 when compared with their male counterparts. The present study reported similar findings as females demonstrated a knee valgus angle at initial ground contact and at maximum knee flexion more than their male counterparts.…”

Do sex differences in patellofemoral joint geometry influence quadriceps forces? What are the therapeutic implications?

“…Clearly, for the purposes of this paper, we are interested in establishing if there are sex 363 differences in quadriceps activation that are independent of movement strategy, and that 364 might be inferred to be a result of the potential sex differences in PFJ geometry (27). Of 365 course, this is challenging, but there is some preliminary evidence of note.…”