Is ski boot sole abrasion a potential ACL injury risk factor for male and female recreational skiers?

Abstract

Objectives: To evaluate the potential impact of ski boot sole abrasion on the ACL injury risk of recreational skiers. Methods: During the past two winter seasons 2016/17 and 2017/18, this retrospective case-control study was conducted in one Austrian ski area. Among a cohort of 148 ACL-injured (51.4% females) and 455 uninjured recreational skiers (43.3% females), age, sex, height, weight, and self-reported skill level were collected by questionnaire, ski length and sidecut radius were notated and sole abrasion of the toe and heel piece of the ski boot was measured using a digital caliper. Results: ACL-injured skiers showed a higher proportion of female (51.4% vs 43.3%, P < 0.001) and less skilled skiers (48.6% vs 20.9%, P < 0.001), and ski length to height ratio was higher (94.7 ± 3.7 vs 93.8 ± 5.0%, P = 0.019) compared to uninjured skiers. ACL-injured skiers used ski boots of greater abrasion at the toe (4.8 ± 1.8 vs 2.4 ± 2.5 mm, P < 0.001) and heel piece (5.4 ± 1.8 vs 3.3 ± 2.3 mm, P < 0.001) compared to controls. Multivariate regression analysis revealed, beside female sex (OR 6.0, 95% CI, 3.1-11.5, P < 0.001), lower skill level (OR 3.2, 95% CI, 1.9-5.4, P < 0.001) and ski length to height ratio (OR 1.1, 95% CI, 1.0-1.2, P < 0.001), sole abrasion at the toe (OR 1.8, 95% CI, 1.5-2.1, P < 0.001) and heel piece (OR 1.4, 95% CI, 1.2-1.6, P < 0.001) to be independently associated with an ACL injury among recreational alpine skiers. Conclusions: Based on the underlying findings, ski boot sole abrasion was found to be an independent risk factor and may contribute to an increased ACL injury risk.