Medalp Imst - Zentrum für ambulante Chirurgie Betriebs

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.

PurposeIt 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.MethodsAmong 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.ResultsThe 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.).ConclusionIn 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 evidenceIII.

BackgroundIn recreational skiing, an ACL injury is one of the most common diagnosis.ObjectiveTo compare equipment-related risk factors between ACL injured and uninjured skiers.DesignCase-Control study over the 3 winter seasons 2016/17–2018/19 in one major Austrian ski resort.Participants248 ACL injured (52% females) and 1054 uninjured skiers (48% females).Assessment of Risk FactorsACL injury was diagnosed by MRI in a sports clinic located in the ski area. Ski length [m] and side cut radius [m] were taken from the information given on the ski and ski length was relativized to body height [%]. Combined height of ski and binding plate [mm] at the front (HF) and back part (HB) of the ski binding, and height at the toe (HT) and heel piece (HH) of the ski boot [mm] were measured with a digital sliding caliper. Quotients between HF and HB as well as between HT and HH were calculated.ResultsACL injured and uninjured skiers did not differ regarding ski length to height ratio (95.3±4.6 vs. 94.9±3.8%, p=.503) or side cut radius (13.9±2.0 vs. 14.4±2.7m, p=.243). Compared to uninjured skiers, ACL injured skiers had a significantly lower absolute mean HF (40.7±5.7 vs. 38.3±4.8 mm, p <.001, d=0.44) and HB (44.9±6.7 vs. 39.2±5.1 mm p<.001, d=0.82) and a higher quotient HF/HB (0.91±0.08 vs. 0.98 vs, p<.001, d=0.75). Moreover, a lower absolute mean HT (16.8±2.3 vs. 13.8±1.6 mm, p <.001, d=1.19) and HH (26.8±2.6 vs. 24.2±1.9 mm, p <.001, d=0.99) and a lower quotient HT/HH (0.63±0.09 vs. 0.57±0.06, p <.001, d= 0.65) of the ski boots were found in ACL injured skiers.ConclusionsACL injured and uninjured skiers differed significantly regarding ski boot sole abrasion and combined height of ski and binding plate, which should be considered as potential risk factors for ACL injuries among recreational skiers.

The purpose of this study was to determine the incidence of the "lateral femoral notch sign" in acute anterior cruciate ligament (ACL) tears and its correlation with lateral meniscal tears. Lateral plain radiographs and sagittal magnetic resonance images (each performed within 1month following injury) of 500 patients with acute and arthroscopically confirmed ACL tears were retrospectively evaluated for depth, length and position of the "lateral femoral notch sign". The accompanying bone bruise was measured, as well. The correlation of the lateral femoral notch sign with high-risk and low-risk pivoting activities as well as with a lateral meniscus tear was evaluated. A total of 26.4% of the patients had a lateral femoral notch sign deeper than 2.0mm with a mean depth of 2.8±0.8mm SD. All lateral femoral notches were situated near or slightly posterior to Blumensaat's line. ACL injuries sustained during high-risk pivoting sports were more prone to a lateral femoral notch sign than ACL injuries in low-risk pivoting sports (r=0.107 vs r=-0.107). Of all patients with a lateral femoral notch sign, 40.2% also had lateral meniscus tears. The correlation between the presence of the lateral femoral notch sign and lateral meniscus tears was statistically significant (p=0.004). In more than one-quarter of patients, plain radiographs may help to establish the diagnosis of an ACL tear. Further, a lateral femoral notch sign greater than 2.0mm also correlates with lateral meniscus tears. Hence, the lateral femoral notch sign is a useful diagnostic tool in daily clinical practice. IV.

Background: In recreational alpine skiing, the knee joint accounts for about one third of all injuries in male and female skiers. However, female recreational skiers have twice the knee injury incidence of male skiers, and the anterior cruciate ligament (ACL) injury risk is 3 times greater in female skiers. Purpose: To evaluate whether leg dominance is a risk factor for noncontact ACL injuries in female recreational skiers. Study Design: Cohort study; Level of evidence, 3. Methods: The relationships between leg dominance, side of knee injury, and gender were analyzed in 65 male and 128 female skiers suffering from a noncontact ACL rupture. Results: Anterior cruciate ligament ruptures of the left knee occurred more frequently in female than in male recreational skiers (68% vs 48%, P = .006). For both genders, in 90%, the right leg was the preferred kicking leg. With regard to leg dominance, female skiers suffered more often from ACL ruptures of their nondominant leg than male skiers (63% vs 45%, P = .020). An adjusted odds ratio of 2.0 (95% confidence interval, 1.0-3.8) was calculated. Conclusion: Female skiers showed a 2-fold higher risk of suffering from an ACL rupture on their nondominant leg. Therefore, leg dominance seems to be a risk factor for noncontact ACL injuries in female recreational skiers.