Foot and Ankle Injuries
With the advent of improved ski boots and bindings, the increase in ACL injuries has corresponded to a reduction in foot and ankle injuries in skiers. In a prospective study of skiing injuries sustained at two ski areas from 1972 through 1994, Deibert et al noted an overall 43% reduction in the number of ankle injuries sustained at the beginning of the study compared with the number of injuries at the end of the study. In contrast, foot and ankle injuries are the most prevalent type of lower extremity injury associated with snowboarding, and one study found that injuries to the ankle comprised approximately 15% of all injuries. Ankle fractures and sprains, associated with either snowboarding or skiing, constituted most of the injuries. Fracture of the lateral process of the talus, which is commonly referred to as the snowboarder's fracture, is an injury relatively unique to snowboarding (Figure 3). Leach and Lower reported that peroneal tendon dislocations and Achilles tendon ruptures typically result from a forward fall and are commonly seen in skiers.
A, Illustration showing the proposed mechanism of injury for the snowboarder's fracture, including eversion and dorsiflexion of the left ankle. B, CT of both ankles demonstrating a normal ankle and an ankle with a displaced fracture of the intraarticular lateral process of the talus (arrow). (Panel B reproduced with permission from Kirkpatrick DP, Hunter RE, Janes PC, et al: The snowboarder's foot and ankle. Am J Sports Med 1998;26:271–277.)
In a study of snowboarding injuries that occurred in Japan over the 2004 to 2005 and 2008 to 2009 snowboarding seasons, Ishimaru et al found that most ankle fractures were supination-external rotation injuries as defined by the Lauge-Hansen classification system, with supination-external rotation type II injuries being the most common. The leading lower extremity, which tends to be contralateral to the upper extremity injury site, was most commonly injured. Ishimaru et al found that collision with other participants or obstacles was the mechanism responsible for most lower extremity injuries. However, other series have reported that falls were the most common mechanism of injury.
Tibial plafond injuries and pilon fractures are common, especially in skiers, secondary to vertical impact and axial load. When the athlete lands on a slope, the energy tends to dissipate while downhill motion continues. Energy does not dissipate when the athlete lands on a flat surface, and this can result in tibial plafond injury.
Although ankle fractures and sprains account for most of the injuries in skiers and snowboarders, Kirkpatrick et al found that metatarsal fractures were the most common foot fracture sustained by the snowboarders in their study, accounting for 29 of 33 foot fractures (88%). This type of fracture is the result of an impact mechanism rather than the rotation mechanism associated with ankle injuries.
In contrast, fracture of the lateral process of the talus is relatively uncommon, accounting for approximately 1.2% to 6.3% of all lower extremity injuries in snowboarders. The mechanism for this injury initially was believed to be ankle dorsiflexion, hindfoot inversion, and axial loading (typically occurring after a jump).[7,39] However, in a cadaver study of talus fractures produced by eversion and dorsiflexion, Funk et al reported that all of the axially loaded and dorsiflexed ankles that were subjected to eversion sustained a fracture, whereas no fractures occurred in axially loaded and dorsiflexed ankles subjected to inversion. Suspicion for fracture of the lateral process of the talus warrants assessment with CT because the fracture can be missed easily on plain radiography (Figure 3, B). The consequences of delayed detection of the injury, which is commonly misdiagnosed as an ankle sprain, can lead to osteonecrosis, nonunion, and subtalar osteoarthritis. The goal of treatment is to maintain joint surface congruity. Open reduction and internal fixation often is warranted for larger displaced fractures (>2 mm), whereas smaller displaced fragments may be excised, with early weight bearing allowed.[7,39] In a study of talus fractures in snowboarders, Valderrabano et al assessed treatment outcomes in 20 patients over a 3.5-year period. American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale scores were considerably higher in patients who underwent surgical treatment for type II injuries with >2 mm of displacement, compared with those who underwent nonsurgical treatment. Subtalar arthritis developed in three patients; however, no statistically significant difference was found between patients who underwent surgery and those who did not. The authors concluded that anatomic reduction and fixation led to better outcomes, particularly in the setting of type II displaced fractures, allowing patients to return to their previous level of sport activity.
J Am Acad Orthop Surg. 2018;26(1):e1-e10. © 2018 American Academy of Orthopaedic Surgeons