Factors associated with self-reported failure of binding release among ACL injured male and female recreational skiers: a catalyst to change ISO binding standards?

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.

Incidence of alpine skiing and snowboarding injuries

BACKGROUND

The incidence of injuries on alpine ski slopes have been assessed using various methods. A decline in injury rate has been observed throughout the literature; however, the actual incidence remains unclear. The purpose of this study was therefore to evaluate the incidence of skiing and snowboarding injuries using large-sample data from an entire geographic state.

METHODS

Data on alpine injuries over the course of five winter seasons between 2017 and 2022 were prospectively collected from the emergency service dispatch center of Tyrol (Austria). The incidence of injuries was assessed in relation to the number of skier days, which was obtained from the chamber of commerce.

RESULTS

A total of 43,283 cases were identified, and a total of 98.1 Mio skier days were registered during the inclusion period of our study, resulting in an overall incidence of 0.44 injuries per 1,000 skier days. This is significantly less than reported from previous studies. From 2017/18 to 2021/22 there was a slight increase in injuries per 1000 skier days with an exception only for the COVID-19 related season 2020/21.

CONCLUSION

Our study showed a significant reduction in the incidence of alpine skiing and snowboarding injuries in comparison with previous studies and should be considered a benchmark for future studies. Long-term studies on the efficacy of safety gear, as well as the influence of ski patrol and air-borne rescues on patient outcome are warranted.

Muscular Fatigue and Quadriceps-to-Hamstring Ratio in Alpine Skiing in Women over 40 Years

(1) Background: In alpine skiing, senior athletes and especially women have a high risk of knee injury. This may also be related to muscular fatigue (MF) of the knee-stabilizing thigh muscles. This study investigates both the evolution of muscle activity (MA) and of MF of the thighs throughout an entire skiing day. (2) Methods: n = 38 female recreational skiers over 40 years of age performed four specific skiing tasks (plough turns, V-steps uphill, turns with short, and middle radii) at specific times, while freely skiing the rest of the day. Surface EMG of the thigh muscle groups (quadriceps and hamstrings) was measured using special wearables (EMG pants). Apart from standard muscle activity parameters, the EMG data were also processed in the frequency domain to calculate the mean frequency and its shift over the day as a metric of muscle fatigue. (3) Results: The EMG pants showed reliable signal quality over the entire day, with BMI not impacting this. MF increased during skiing before and for both muscle groups significantly (p < 0.006) during lunch. MF, however, was not reflected in the quadriceps-hamstrings ratio. The plough manoeuvre seems to require significantly (p < 0.003) more muscle dynamics than the three other tasks. (4) Conclusion: MF may be quantified over an entire skiing day and thus fatigue information could be given to the skier. This is of major importance for skiers at the beginner level dominantly performing plough turns. Crucial for all skiers: There is no regenerative effect of a 45-min lunch break.

[Winter sports nation Germany-injuries in alpine ski racing and mass sports : Statistics and injury mechanisms in winter sports and current trends in sports science]

BACKGROUND

In Germany, winter sports are very popular. About 7 million people go skiing at least 6 days per season. The German national winter teams won about 50% of the Olympic medals for the last several Olympic games. The downside of winter sports is the everlasting high number of injuries. This affects both professionals and the large number of amateur skiers.

TREND

The ASU institute of German insurances and skiing association find a decreasing number of injuries overall and a decreasing number of inpatient stays in hospitals. Still, the knee is the most injured region of the body. There is an increasing number of ACL ruptures within the knee lesions. The numbers in professional teams have been monitored with the FIS surveillance system since 2006. The highest rates of knee injuries (41.3%) are found with the ski world cup teams all over the world. The most common injury mechanism is the slip-catch mechanism. In current sports science examinations of the German skiing association there are extremely high forces of more than three times the body weight found on the body during skiing. Slalom skiing is especially affected. To understand the popular carving ski technology, you must know about the waist and the edge angle of the ski. There can be enormous forces coming along with the skis that can hardly be controlled by the skier.

Emergency Service Assistance for Injuries on Alpine Ski Slopes: A Cross-Sectional Study

OBJECTIVES

Injuries on alpine ski slopes have been described in cohorts of a reasonable sample size, but constant improvements in safety gear, increased use of airborne rescue, and safety measures during the coronavirus disease 2019 (COVID-19) pandemic mandate re-evaluation. Therefore, the purpose of this study was to evaluate skiing and snowboarding injuries, effectiveness of airborne rescue, and impact of the COVID-19 pandemic on a large sample size.

METHODS

Data on alpine injuries were prospectively collected from the state emergency services dispatch center in the state of Tyrol (Austria). A total of 10,143 patients were identified, with an average age of 33.5 years (SD = 20.36). The ski patrol was involved in 8,606 cases (84.9%) and some patients (n = 1,536; 15.1%) required helicopter rescue.

RESULTS

A total of 10,143 patients were identified from the dataset of the emergency dispatch center. The most frequently injured region was the knee (30.2%), and it was followed by the shoulder (12.9%), the lower leg (9.5%), and the head/skull (9.5%).

CONCLUSION

The present findings indicate that the most frequent site of injuries on alpine slopes is the knee, and life-threatening injuries are rare. Airborne rescue is very time-effective, however clinical studies with patient follow-up should be emphasized to determine the impact of airborne rescue on patient outcome. The present findings indicate that the duration of all rescue operations has been prolonged as a result of the introduction of safety measures during the COVID-19 pandemic.

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.

Method to Investigate Multi-Axis Release Action of Ski Safety Bindings: A New Approach for Testing in Research and Development

The authors developed and elaborated on a new method to release ski bindings by utilizing an industrial robot to simulate release movement showing a spatial repeatability of ± 0.06 mm. The parametric programming of the release parameters gave free control while executing repeatable release tests. A series of different motion patterns were performed, on the one hand, to test the applicability of the setup to the simulation of motion patterns and, on the other, to check for the impact of the ski deformations like ski deflections within the range of −5 mm to −85 mm, on the safety bindings' release forces. As certain falling mechanisms are related to knee injury, which is the most common severe injury in alpine skiing, this testing method can be used to develop related displacement movements in future. This movements do not necessarily accord with the directional release mechanics of safety ski bindings. The authors specify the developed testing apparatus as device for force measurements in 3D with an accuracy of ± 0.5% in boot-sole-plane. The intention behind this development is to enable faster, more versatile and adaptive testing procedures in R&D.

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.

A Prospective Injury Surveillance Study on Ski Touring

Background:

Ski touring is an outdoor sport with growing popularity in alpine countries. Information about injuries in ski touring is limited.

Purpose:

To determine injury rates, mechanisms, causes, and risk factors in ski touring.

Study Design:

Descriptive epidemiology study.

Methods:

Between November 2015 and May 2016, a total of 191 participants from the Alps region were prospectively tracked via personalized online questionnaires. Injury rates were calculated per 1000 hours of sports exposure. Risk factors were assessed per multivariate logistic regression analysis.

Results:

A total of 3900 ski tours were performed, with 10,955 hours and 4,108,503 m in height ascension (uphill) recorded. The overall injury rate was 2.5 injuries per 1000 hours of ski touring. A total of 27 injury-events were reported, of which 18 (67%) were classified as mild, 7 (26%) as moderate, and 2 (7%) as severe. Hands (28%) and knees (16%) were the most commonly involved anatomic regions. Most injuries were limited to the soft tissue, such as bruises (31%) and abrasions (18%). Significantly more injuries happened during the descent (n = 17; 63%) than during the ascent (n = 6; 22%) (odds ratio, 5.96; P = .004), while poor weather conditions, icy surface, and inattentiveness were the most often reported reasons for injury. Sidecountry ski touring was identified as the only significant independent risk factor for injury (P < .001).

Conclusion:

In this prospective injury surveillance study, the majority of ski touring injuries were mild and limited to the soft tissue. Ski touring injuries were more likely to happen during the descent of a tour, and sidecountry ski touring was the only significant independent risk factor for injury. Bad weather, icy surface, and inattentiveness were found to be the leading causes for an injury-event in this study.

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.

Comprehensive Review of Skiing and Snowboarding Injuries

Skiing and snowboarding have increased in popularity since the 1960s. Both sports are responsible for a substantial number of musculoskeletal injuries treated annually by orthopaedic surgeons. Specific injury patterns and mechanisms associated with skiing and snowboarding have been identified. No anatomic location is exempt from injury, including the head, spine, pelvis, and upper and lower extremities. In these sports, characteristic injury mechanisms often are related to the position of the limbs during injury, the athlete's expertise level, and equipment design. Controversy exists about the effectiveness of knee bracing and wrist guards in reducing the incidence of these injuries. Understanding these injury patterns, proper training, and the use of injury prevention measures, such as protective equipment, may reduce the overall incidence of these potentially debilitating injuries.

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.