Risk Factors for an Anterior Cruciate Ligament Injury Are Hardly Comparable Between Ski Racers and Recreational Alpine Skiers

We read with great interest the recently published article by Bhatt et al.1 titled “Multiple Intrinsic and Extrinsic Factors Increase the Risk of Anterior Cruciate Ligament Injury in Skiers: A Systematic Review.” We commend the authors for their review, which shows that anterior cruciate ligament (ACL) injuries in alpine skiing have multiple causes, resulting from a combination of intrinsic factors (e.g., skill level, risk-taking behavior, and physical fitness) and extrinsic factors (e.g., equipment and environmental conditions). To this end, the authors synthesized studies involving elite and junior ski racers, as well as recreational skiers. However, in our view, the risk factors presented cannot be applied equally to ski racing and recreational skiing. Ski racing involves navigating tight gates (slalom and giant slalom) or wide gates (super G and downhill) on steep, hard-packed, or icy slopes, which are typically separated from public skiing areas by barriers and safety nets. This is not the case in recreational alpine skiing. Male and female ski racers, particularly those ranked in the top 30 of the world rankings, are likely to possess the highest skill level and engage in the greatest risk-taking behavior. They are also likely to have the highest possible level of physical fitness and use meticulously prepared skis with extreme edge tuning. They are also likely to wear individually customized ski boots. This suggests that factors commonly associated with an increased risk of ACL injury in recreational alpine skiing, such as advanced age (over 40 years), lower skill level, reduced physical fitness, increased risk-taking behavior (particularly among males), abrasion of ski boot soles, rented skis, and suboptimal slope conditions, are unlikely to be significant contributors to ACL injuries in ski racers. Additionally, ski racing safety bindings are usually tightened to their maximum setting to prevent unintended release while skiing. Nevertheless, there are few top racers who have not sustained one or more severe knee injuries over the course of their careers.2, 3 Furthermore, severe knee injuries in ski racing often appear to occur—although this has not yet been scientifically studied—when skis become entangled in the safety net following a fall, resulting in extreme rotational forces on the knee joint. Therefore, it is plausible that distinct differences in ACL injury mechanisms exist between ski racers4 and recreational skiers.5 From our perspective, it would be particularly valuable to differentiate between intrinsic and extrinsic risk factors in alpine skiing for both ski racing and recreational skiing and to develop preventive measures based on evidence that are tailored to these specific contexts. The authors (G.R., M.P., M.B.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.