Summary: A 28-year-old man presented to the emergency department complaining of
acute left ankle pain. The patient relayed a history of trauma to the
ankle during physical training but was unable to describe the position
of his foot at the time of injury. Physical examination revealed point
tenderness over the lateral aspect of the ankle without associated
swelling or erythema. Conventional radiography of the ankle (Figure 1)
showed an abnormality that was further evaluated with ankle computed
tomography (CT) (Figure 2).
Fracture of the lateral process of the talus (snowboarder’s fracture)
Conventional radiographic evaluation of the ankle showed a subtle
fracture of the lateral process of the talus. An ankle CT, ordered to
evaluate the extent of osseous injury, revealed extension of the
fracture to involve a small portion of the inferolateral articular
The lateral process of the talus is a large, wedge-shaped osseous
projection that extends laterally from the body of the talus. Its
inferolateral surface comprises a portion of the posterior facet of the
talocalcaneal joint, while its superolateral surface articulates with
the lateral malleolus.1
Its functions include lateral
stabilization of the ankle, weight bearing by means of its articulation
with the ﬁbula, and subtalar motion. The lateral process of the talus is
aided by the lateral talocalcaneal ligament that extends between it and
During ankle inversion, contact at the
posterior talocalcaneal joint is maintained by the lateral process. With
concurrent dorsiﬂexion, increased forces transmitted via the ﬁbula can
lead to fracture.1
This entity has been recognized as a cause
of acute ankle pain in the younger population as the sport of
snowboarding has increased in popularity.3
routinely requires landing with the feet oriented in a vulnerable
position, making this fracture a common hazard to snowboarders.2,4
Approximately 40% of lateral talar process fractures are improperly diagnosed at initial presentation.3
typically present with acute onset of pain over the anterolateral
ankle, with varying degrees of swelling. Pinpoint tenderness is
typically localized over the lateral process. Radiographic ﬁndings are
subtle, with the lateral view providing the best visualization of the
lateral process. When radiographs are negative and clinical suspicion
remains high, ankle CT—optimally with coronal and sagittal
reformations—is the deﬁnitive diagnostic study.
diagnose and properly treat a fracture of the lateral process of the
talus can result in long-term disability caused by subtalar arthrosis,
mal-union, or nonunion.5 These fractures have been classiﬁed into 3 types by Hawkins,3 with
treatment based accordingly. Type I is a simple fracture that extends
from the articular surface of the posterior talocalcaneal joint space to
the taloﬁbular articular surface (as observed in the case reported
here) and can be treated with casting; internal ﬁxation is usually
reserved for fragments >1 cm or fragment displacement ≥2 mm. Type II
is a comminuted fracture of the lateral process. Smaller fragments
should be excised while the larger component is reduced and ﬁxed
internally to decrease the likelihood of future instability and
persistent symptomatology. Type III is a chip fracture on the
anteroinferior portion of the lateral process that is limited to the
subtalar joint; this type may be treated conservatively or surgically,
depending upon the severity of the injury.3
Fractures of the lateral process of the talus are infrequent but may be a
signiﬁcant source of acute ankle pain, particularly in the adolescent
and young adult population whose growing participation in the sport of
snowboarding puts them at particular risk for this inversion-dorsiﬂexion
injury. Often misdiagnosed as a severe lateral ankle sprain, failure to
recognize and treat this entity early can result in signiﬁcant
morbidity in otherwise healthy young adults. Essential to the diagnosis
are an elevated index of suspicion in the proper clinical presentation
with a thorough radiographic evaluation, including CT ankle evaluation
if radiographs are equivocal or only suggestive and clinical suspicion
of a fracture remains.
- Leibner ED, Simanovsky N, Abu-Sneinah K, et al.
Fractures of the lateral process of the talus in children. J Pediatr
Orthop B. 2001;10:68-72.
- Cantrell MW, Tarquinio TA. Fracture of the lateral process of the talus. Orthopedics. 2000;23:55-58.
- Hawkins LG. Fracture of the lateral process of the talus. J Bone Joint Surg Am. 1965;47:1170-1175.
- Mills HJ, Horne G. Fractures of the lateral process of the talus. Aust N Z J Surg. 1987;57:643-646.
- Boon AJ, Smith J, Zobitz ME, Amrami KM. Snowboarder’s talus fracture: Mechanism of injury. Am J Sports Med. 2001;29:333-338.