Avulsion Fractures of Posterior Calcaneal Tuberosity: Identification of Prognostic Factors and Classification

Avulsion fractures of the posterior calcaneal tuberosity are rare injuries, and little is known about the underlying factors, outcomes, and prognosis. Furthermore, classifications described previously focus on fracture morphology, with uncertain clinical utility. We present the results of a retrospective study of 21 patients treated for this pathology from January 2002 to December 2015. Features analyzed were age; sex; mechanism of injury; medical comorbidities; type of fracture, as proposed by Beavis; fracture displacement; fragment size; type of treatment; complications; need for secondary surgery; and the American Orthopaedic Foot and Ankle Society score after treatment and follow-up care. Mean age was 56.95years. A total of 61.9% were females, and 71.4% were secondary to low-energy trauma. In addition, 19% were diabetic. Mean follow-up was 57.24 months. Surgery was performed in 81%. Complications rate was 61.9%, and secondary surgery was needed in 38.1%. Mean fracture displacement was significantly higher when complications occurred (25.91mm versus 7.61 mm) (p = .03) and when soft tissues complications appeared (30.65mm versus 14.68 mm) (p = .02). Female gender was associated with the secondary loss of reduction (p = .04). The Beavis classification was not related significantly with any outcome variable. When fracture displacement was ≥2cm, complication rate increased from 30% to 90.9% (p = .008) and soft tissue compromise increased from 0% to 45.45% (p = .035). A new classification system with prognostic value is described, based on fracture displacement. We present 1 of the largest series published to date; fracture displacement is a major variable that influences the outcomes of these injuries, and a new classification attending to a prognostic factor is developed.