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

Individual behavioral and sporting risk factors affecting injuries in recreational skiers and snowboarders: a case-control study

This case-control study aimed to analysis of the relationship between individual behaviours and sports risk factors and injuries among skiers and snowboarders. During the 2021-2022 winter season, 1132 injured and 1069 non-injured skiers and snowboarders were surveyed regarding demographic, self-reported individual behavioural and sporting characteristics. Multivariate regression analysis revealed previous snow-sports injury (OR: 26.39, 95% CI: 13.32-52.31, P < 0.001), nervousness (OR: 3.78, 95% CI: 2.91-4.90, P < 0.001), calm (OR: 1.90, 95% CI: 1.46-2.48, P < 0.001) and fearful (OR: 20.60, 95% CI: 11.45-37.04, P < 0.001) emotional states, and higher risk-taking behaviours (OR: 3.72, 95% CI: 2.87-4.83, P < 0.001) were important risk factors associated with injuries to all skiers and snowboarders. Compared to snowboarders, the risk of injury to skiers was more likely to increase as the length of their skiing experience increases. Emotional and cognitive levels appear to be important conditions that influence injuries to skiers and snowboarders, a proper understanding of the potential interactions between cognition and behaviour appears to be important for public ski safety management.

Extrinsic Risk Factors for Primary Noncontact Anterior Cruciate Ligament Injury in Adolescents Aged between 14 and 18 years: A Systematic Review

BACKGROUND

Adolescents present a high incidence of ACL injury compared with other age groups. Examining the risk factors that predispose adolescents to primary noncontact ACL injury is a key strategy to decrease the number of injuries in this population.

OBJECTIVE

The aim of this systematic review was to summarise the existing literature investigating extrinsic risk factors that have been linked with primary noncontact ACL injury risk (identified either using ACL injury occurrence or using screening tests measuring biomechanical mechanisms for noncontact ACL injury) in adolescents including research investigating: (1) the association between extrinsic risk factors and primary noncontact ACL injury risk; and (2) whether primary noncontact ACL injury risk was different in populations or groups exposed to different extrinsic risk factors in adolescents.

METHODS

The same search strategy was used in MEDLINE, SPORTDiscus, CINAHL, PubMed and Embase. Articles were included if: written in English; published in peer-reviewed journals; investigating and discussing primary noncontact ACL injury risk associated with extrinsic risk factors; they were original research articles with an observational design; and participants presented a mean age ranging between 14 and 18 years. The Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies (QATOCCS) was used to assess the quality and risk of bias of the articles included in this systematic review.

RESULTS

The systematic review included 16 eligible articles published up to August 2022 about extrinsic risk factors for primary noncontact ACL injury including: sport (8 studies); sport exposure amount (5); sport level (3); sport season (1); environment (2); equipment (1). Differences in biomechanical risk factors predisposing to ACL injury were reported by sport in female adolescents playing basketball and soccer; however, no good evidence of differences in primary noncontact ACL injury rate by sport was reported in both male and female adolescents. There was contrasting evidence about associations between sport exposure and biomechanical and neuromuscular risk factors predisposing to ACL injury or primary noncontact ACL injury rate in both male and female adolescent players from different sports. There was weak evidence of differences in biomechanical risk factors predisposing to ACL injury by environmental condition in both male and female adolescents playing soccer and season phase in male adolescents playing basketball. Lastly, few good-quality articles suggested that higher sport level might be associated with increased primary noncontact ACL injury rate in female adolescents playing basketball and floorball and that bracing might not prevent primary noncontact ACL injuries in both male and female adolescent players from different sports.

DISCUSSION

The findings emphasise the need for further research to clarify the evidence about extrinsic risk factors and primary noncontact ACL injury in adolescents to develop ACL injury prevention guidelines that would help practitioners and researchers identify adolescents at risk and design future interventions. Future epidemiological studies should collect data about extrinsic factors as well as data about primary noncontact injury separately from secondary injuries or contact injuries to better inform primary noncontact ACL injury prevention in adolescents.

REGISTRATION

https://doi.org/10.17605/OSF.IO/VM82F (11/08/2021).

Impact of Environmental Factors on the ACL Injury Risk in Recreational Alpine Skiing

In recreational alpine skiing, an ACL injury represents the most common injury. Skiing is a complex activity where the skier interacts with the environment, such as weather, snow conditions, temperature, etc. Thus, the aim of this study was to evaluate the potential impact of environmental factors on ACL injury risk in recreational alpine skiers. Among a cohort of 392 ACL-injured skiers and 392 uninjured controls matched for sex and skiing skill, environmental factors were collected by questionnaire. Factors included weather conditions, snow conditions, perceived temperature, and slope difficulty at the time-point of the accident (ACL-injured skiers) or of questioning during the ski day (uninjured controls).Multiple logistic regression revealed that in addition to age, five environmental factors were significantly predictive of an ACL injury: fresh snow (OR 10.5), grippy snow (OR 7.8), icy slope condition (OR 12.4), very cold/cold perceived temperature (OR 1.6), and skiing on easy slopes (OR 6.9). In conclusion, besides age, environmental factors such as fresh and grippy snow, icy slope conditions, low temperatures, and flat slopes are associated with an increased ACL injury risk in recreational alpine skiing. Those factors are at least partly modifiable and should be taken into consideration for preventive strategies.

Association of personal and equipment-related factors on ACL injury risk in alpine skiers with cautious or risk-taking behaviour: A case-control study

Background

In recreational alpine skiing ACL injury risk depends on the interaction of individual characteristics and behaviours as well as on equipment-related factors.

Aim

to evaluate if and to what extent personal characteristics and equipment-related parameters are associated with ACL injury risk in cautious and risk-taking recreational alpine skiers.

Methods

A retrospective questionnaire-based, case-control study of ACL-injured and uninjured in a cohort of cautious as well as risk-taking recreational skiers was conducted. Participants self-reported their demographics, skiing skill level, and risk-taking behaviour. Ski length, side-cut radius, widths of the tip, waist, and tail were recorded from each participant's skis. Standing heights at the front and rear components of the ski binding were measured with a digital sliding caliper, and a standing height ratio between the front and rear components was calculated. Ski boot sole abrasion at the toe and heel pieces was also measured with the digital sliding caliper.

Results

In total, 1068 recreational skiers (50.8% females) with a mean age of 37.8 ± 12.3 years participated, of whom 193 (22.0%) sustained an ACL injury, and 330 (30.9%) participants reported a risk-taking behaviour. Results of the multiple logistic regression analyses revealed that a higher age, a lower skill level, a higher standing height ratio, and greater ski boot sole abrasion at the toe as well as heel pieces were independently associated with an increased ACL injury risk in both the cautious and the risk-taking group. Among cautious skiers, a longer ski length was an additional significant risk factor for sustaining an ACL injury. In conclusion, the same personal and equipment related characteristics contribute to an increase in the ACL injury risk regardless of risk-taking behaviour, with the only difference that longer skis represent an additional risk factor in cautious skiers.

Skill-Specific Differences in Equipment-Related Risk Factors for ACL Injury in Male and Female Recreational Skiers

Background

In recreational alpine skiing, the anterior cruciate ligament (ACL) is affected in approximately 50% of serious knee injuries. There are established sex-based and skill-based differences in ACL injury risk, but the potential impact of equipment used (eg, skis, bindings, and boots) has not been evaluated.

Purpose

To evaluate individual and equipment-related risk factors for an ACL injury depending on sex and skill level.

Study Design

Case-control study; Level of evidence, 3.

Methods

This was a retrospective questionnaire-based, case-control study of female and male skiers with and without ACL injuries during 6 winter seasons (from 2014-2015 to 2019-2020). Demographic data, skill level, equipment specifications, risk-taking behavior, and ownership of ski equipment were recorded. Ski geometry (ski length; sidecut radius; and widths of the tip, waist, and tail) was taken from each participant's ski. The standing heights of the front and back part of the ski binding were measured using a digital sliding caliper, and the standing height ratio was calculated. Abrasion of the ski boot sole was also measured at the toe and heel. Participants were divided by sex into less and more skilled skiers.

Results

A total of 1817 recreational skiers participated in this study, of whom 392 (21.6%) sustained an ACL injury. A greater standing height ratio and more abrasion at the toe of the boot sole were associated with increased ACL injury risk in both sexes, independent of the skill level. Riskier behavior increased the injury risk only in male skiers, independent of the skill level, and longer skis increased the injury risk only in less skilled female skiers. Older age, the use of rented/borrowed skis, and more abrasion at the heel of the boot sole were independent risk factors for ACL injury in the more skilled skiers of both sexes.

Conclusion

Individual and equipment-related risk factors for an ACL injury partly differed according to skill level and sex. Consideration of the demonstrated equipment-related factors should be implemented in order to reduce ACL injuries in recreational skiers.

A Comparison of ACL Injury Risk, Ski Geometry and Standing Height Parameters between Skiers with Rented and with Owned Skis

to evaluate if ACL injuries are associated with recreational skiers using rented skis and whether individual factors, ski geometry parameters and standing heights differ between skiers who rented or owned skis. A retrospective questionnaire-based, case-control study of ACL-injured and uninjured recreational skiers was conducted during six winter seasons. Age, sex, body height, body weight, nationality, ownership of skis, skill level, risk-taking behavior, ski length, side-cut radius, widths of the tip, waist, and tail, and the standing heights at the front and rear components of the ski binding were assessed. Additionally, ratios between ski widths and a standing height ratio were calculated. Altogether, 1780 skiers (48.9% females) with a mean age of 39.2 ± 13.0 years participated, of whom 22.0% sustained an ACL injury and 32.3% rented skis. ACL injury risk was significantly associated with rented skis (OR 3.2, 95% CI 2.5-4.0). Compared to skiers using own skis, participants who rented skis were more likely female, smaller and lighter, tourists, less skilled and more cautious. In comparison to owned skis, rented skis showed significantly lower mean values in ski length, side-cut radius, ski widths, and for the three ski widths ratios. Additionally, standing heights were significantly lower while standing height ratio was higher for rented skis. Beside individual factors, equipment-related factors should be considered when renting skis in order to reduce ACL injury risk.

Impact of ski geometry data and standing height ratio on the ACL injury risk and its use for prevention in recreational skiers

OBJECTIVES

To evaluate the impact of ski geometry data and standing height ratio on anterior cruciate ligament (ACL) injury risk of male and female recreational skiers.

METHODS

A retrospective questionnaire-based, case-control study of ACL-injured and uninjured recreational skiers was conducted during six consecutive winter seasons. Ski geometry data (ski length, side-cut radius, widths of the tip, waist and tail) were recorded from each participant's skis. Standing heights at the front and rear components of the ski binding were measured with a digital sliding calliper, and the standing height ratio between the front and rear was calculated.

RESULTS

A total of 1817 recreational skiers participated in this study, of whom 392 (21.6%) sustained an ACL injury. Multiple logistic regression analysis indicates a higher age, a lower skill level and riskier behaviour as independent individual risk factors associated with an ACL injury. An increase in ski length, tip width of the ski, standing height at the rear ski binding component, and in standing height ratio were found to be independent equipment-related risk factors for an ACL injury.

CONCLUSION

Reduced ski length, narrower ski tip width, lower rear standing height and a lower standing height ratio (ie, rear component of the ski binding is more elevated compared with the front component) were associated with a reduced likelihood for ACL injury. When buying or renting skis, these parameters could be considered to reduce the likelihood of ACL injury in recreational skiers.

Ski-geometric parameters do not differ between ACL injury mechanisms in recreational alpine skiing

PURPOSE

It is not known so far if ski-equipment-related factors differ between the ACL injury mechanisms, potentially influencing the circumstances and causes of falling, finally resulting in ACL injury. More specifically focusing on the injury mechanisms will provide a deeper understanding of injury causation. The aim of the study was to evaluate whether ACL injury mechanisms in recreational alpine skiing differ with regard to ski-geometric parameters, self-reported circumstances and causes of accident and injury severity.

METHODS

Among a cohort of 392 ACL-injured (57.9% females) skiers, age, sex, height, weight, skill level, risk-taking behavior, circumstances and causes of accident, and ACL injury severity were collected by questionnaire. Additionally, patients had to recall their type of fall (ACL injury mechanism) by classifying forward and backward falls with and without body rotation. Ski length, side cut radius and widths of the tip, waist and tail were directly notated from the ski.

RESULTS

The forward fall with body rotation was the most common reported ACL injury mechanism (63%). A riskier behavior was associated with forward falls without body rotation. Ski-geometric parameters did not significantly influence the type of ACL injury mechanism. Regarding accident characteristics, catching an edge of the ski was more frequent (p < 0.001) the cause for forward falls (75% and 67%) when compared to the backward falls (46 and 15%) and executing a turn was the most frequent action in all falls (39-68%). A complete rupture of the ACL (66-70%) was more commonly reported than a partial tear (30-34%) among all four non-contact ACL injury mechanisms (n.s.).

CONCLUSION

In contrast to risk-taking behavior and accident characteristics, ski-geometric parameters and injury severity do not significantly differ between ACL injury mechanisms in recreational skiing. Thus, an individual skiing style seems to have more impact on ACL injury mechanisms than ski equipment. Future studies should evaluate potential effects of ski geometry on the incidence of ACL injury.

LEVEL OF EVIDENCE

III.

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.

Sex differences in the knee orthopaedic injury patterns among recreational alpine skiers

Background

Although studies have reported the sex differences in injury patterns among recreational skiers, the findings are still conflicting. This study aims to analyse the sex differences of orthopaedic knee injuries that occurred during alpine skiing.

Methods

A total of 306 recreational alpine skiers (125 females and 181 males) who sustained knee surgeries between June 2016 and December 2018 participated in this study. Age, height, weight, and physical activity level of the patients were recorded. The orthopaedic knee injury patterns were analysed based on the diagnosis given by the physicians.

Results

Male skiers (17.13%) had a higher proportion of multiple knee ligament injuries than females (6.40%). The combined anterior cruciate ligament (ACL) and medial collateral ligament injury were the most common injury types in both females and males, with ACL injury being more prevalent for females (79.20%) than that in males (56.35%). The proportion of female skiers (17.6%) with vigorous-intensity activity level was significantly lower than that of males (30.9%). Female skiers had lower body height, body weight, and body mass index than male skiers (P <  0.001).

Conclusions

ACL injury is the most common orthopaedic injury among both female and male knee-injured recreational skiers. The proportion of females with an ACL injury is higher than that of males, but the proportion of multiple knee ligament injuries is lower than that of males. More male recreational skiers have vigorous-intensity activity level habits in daily life than females.

Are Risk-Taking and Ski Helmet Use Associated with an ACL Injury in Recreational Alpine Skiing?

According to the risk compensation hypothesis, the use of a ski helmet might provide a false sense of security, resulting in a riskier behavior by skiing faster or more aggressively, which might lead to an increased injury risk. Injury of the anterior cruciate ligament (ACL) is a common diagnosis in downhill skiers. Thus, the aim of the study was to evaluate the potential impact of risk-taking and ski helmet use on ACL injury risk in recreational skiing. Eighty-two ACL injured and 446 uninjured skiers with a mean age of 37.3 ± 11.9 years (52% females) were surveyed during the winter season 2018/19 about age, sex, self-reported risk-taking behavior, self-reported skill level, perceived speed, and ski helmet use. Multiple regression analysis revealed that older age (OR: 1.3, 95% CI: 1.2–1.4), riskier behavior (OR: 5.4, 95% CI: 2.8–10.5), and lower skill level (OR: 6.7, 95% CI: 3.4–13.3) were found to be factors associated with ACL injury, while ski helmet use was not. In conclusion, no support for the risk compensation hypothesis was found with regard to ACL injuries. Therefore, we doubt that ski helmet use increases the risk for ACL injury and recommend wearing a ski helmet due to reported protective effects.

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.