[Are there Sex Differences Regarding Ski Length to Height Ratio, Ski Length to Weight Ratio, Sidecut Radius and Ski Boot Sole Abrasion among ACL Injured Male and Female Skiers?]

In recreational alpine skiing, the ACL is predominantly injured in all knee injuries needing hospitalisation

PURPOSE

The knee joint still represents the most frequent anatomical injury location accounting for about one-third of all injuries in recreational alpine skiers. However, comprehensive information on current knee injury patterns in this populations is sparse.

METHODS

During the winter seasons 2016/17 and 2019/20, this retrospective questionnaire-based study was conducted in an Austrian sportclinic situated in a large ski area. Among a cohort of 282 recreational skiers (51.8% females), all injuries were diagnosed by the use of magnetic resonance imaging. Additionally, data were recorded on anthropometric characteristics, the perceived speed at the moment of injury, type of fall, physical fitness, self-reported skill level and risk-taking behaviour.

RESULTS

The anterior cruciate ligament (ACL) was injured in all knee injuries recorded. Of the total study sample, 64.5% (n = 182) were ACL injuries with concomitant injuries and about 35.5% (n = 100) were isolated ACL injuries, not involving any other structures of the knee joint. In general, most common concomitant injury diagnoses among ACL-injured recreational alpine skiers were injuries of the medial collateral ligament (MCL) (n = 92, 50.5%), medial meniscus (MM) (n = 73, 40.1%) and lateral collateral ligament (LCL) (n = 41, 22.5%). No significant differences regarding additionally recorded characteristics were found between ACL-injured individuals with concomitant injuries and those with isolated ACL injury.

CONCLUSIONS

Whereas, before the introduction of carving skis, the MCL was reported being the most common injured part of the knee, currently, the majority of knee injuries are ACL injuries accompanied by injury of other knee joint structures, i.e. the MCL, MM and LCL.

LEVEL OF EVIDENCE

Level III.

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

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.

Impact of lowering ski binding settings on the outcome of the self-release test of ski bindings among female recreational skiers

Background and purpose

The ability to successfully self-release the ski binding can prevent skiing-related injuries of the lower extremities. Failure of binding release associated with a knee injury is significantly higher among females compared to males. The International Standards Organization ISO 11088 standard for binding setting values allows a lowering by 15% upon request of the skier. Thus, the aim of this study was to evaluate the impact of lowered ski binding settings by 15% on the outcome of the self-release test among female recreational skiers.

Materials and methods

In this randomized single-blinded study, a cohort of 20 females (24.5±2.7 years) performed the self-release test in the laboratory thrice with each leg under two conditions: 1) with an actual ISO 11088 setting and 2) with a setting lowered by 15%. For each attempt, torques calculated via the force plate were normalized to torques measured by a binding adjustment system (relative release torque, RRT).

Results

Among 240 trials in total, more females were significantly able to self-release their ski bindings with lowered binding settings when compared to their actual ISO settings (53% vs 9%, p<0.001). Thirteen females (65%) were able to release their bindings at least once with both legs with lowered binding settings compared to only three females (15%) with their actual binding settings (p<0.001). Mean RRT of all failure of binding release trials significantly differed between lowered and actual binding settings (58.6%±22.2% vs 50.5%±20.4%, p=0.003).

Conclusion

Four times more females were able to self-release their ski bindings at least once with both legs with a 15% lowered binding setting compared to their normal ISO 11088 setting. The fact that the ISO standard accepts a lowering by 15% upon request of the skier could represent an important measure to prevent knee injuries, especially for female recreational skiers.