SLR - April 2022 - Tommy H. Yates
Reference: Rammelt S, Bartonicek J, and Kroker L. Pathoanatomy of the Anterolateral Tibial Fragment in Ankle Fractures. JBJS, 2021, 104: 353-363.Level of Evidence: IV, retrospective review
Scientific Literature Review
Reviewed By: Tommy H. Yates, DPM
Residency Program: Highlands/Presbyterian-St. Luke’s Medical Center – Denver, CO
Podiatric Relevance: There is a recent shift in focus towards surgical decision-making regarding a fourth, “anterior malleolus,” otherwise known as the anterolateral tibial tubercle, or the tubercle of Tillaux-Chaput fractures. These are reported to be very rare in adults given the maturity of the distal tibial growth plate after the age of 14. The author’s aim was to answer whether or not there are any significant associations between Tillaux-Chaput fractures in adults and other fracture patterns or osseous injuries that one might encounter on a CT scan in the setting of an acute ankle fracture.
Methods: Inclusion criteria consisted of patients with acute ankle fractures and accompanying CT scans from the time of injury, between January 2010 and December 2018, at two different level I trauma centers.
The authors excluded pilon fractures, pathologic/neuropathic fractures, and patients less than 18 years of age. In total, there were 140 acute ankle fractures with a Tillaux-Chaput fragment identified.
All Tillaux-Chaput fractures were grouped according to a validated classification system based on CT scan findings:
Type I = extra-articular avulsion.
Type II = involvement of the fibular incisura.
Type III = impaction of the tibial plafond.
These fractures were then cross-referenced with any other osseous injuries, including medial, lateral, and posterior malleolar fractures, as well as OCDs.
Results: The overall prevalence over the 9-year study span for a Tillaux-Chaput fracture in an adult was 12.6 percent, and these fractures tended to occur more often in pronation type Lauge-Hansen injuries.
74 patients (53 percent) had a type I fracture, while 50 (36 percent) were classified as type II and 16 (11 percent) were type III.
93 patients (66 percent) had a concomitant medial malleolar fracture, 96 (69 percent) had a posterior malleolar fracture, and 122 patients (87 percent) had a fibular fracture.
There were only 10 OCDs identified (7 percent). Six of these were identified as “kissing lesions” due to their intimate association with type III Tillaux-Chaput fractures.
Only six patients (4 percent) had an isolated Tillaux-Chaput fracture.
There was a trend towards decreasing size of the Tillaux-Chaput fragment as the size of the posterior malleolar fragment increased.
Conclusions: Author’s conclusions: isolated Tillaux-Chaput fractures rarely occur in isolation in adults, though they tend to occur more frequently in pronation type Lauge-Hansen injuries; type I Tillaux-Chaput fractures are by far the most common (53 percent of such fractures); type III fractures, though less common, are associated with Lauge-Hansen PAB type fracture patterns and have a predilection for “kissing lesions” on the talar dome.
My conclusions: in patients for whom surgical intervention is warranted, fixation of the Tillaux-Chaput fracture makes sense no matter the fracture pattern or associated injuries, as the AiTFL confers roughly 33 percent of syndesmotic stability and theoretically helps to restore the fibular incisura.
How might this help future patients: it would be interesting to see future studies build on this and examine a potential cutoff for Tillaux-Chaput fragment size as it relates to imparting stability to the fibular incisura; this may help surgeons decide which Tillaux-Chaput fractures ought to be fixated versus not.