August Tuan MD, Presenter: Nothing to Disclose

Tudor Hesketh Hughes MD, Abstract Co-Author: Nothing to Disclose

To determine whether low ankle sprains may be reclassified as high ankle sprains by the presence of posterior tibiofibular ligament ossification on followup traumatic ankle radiographs. This implies injury to the posterior tibiofibular ligament when initial radiographs did not show injury or a posterior malleolar fracture.

The patient pool consisted of all ankle radiographs taken at our institution during the past three years. Only patients with initial and followup ankle radiographs were included in the study. Ankle radiographs were reviewed to determine if interval ossification of the posterior tibiofibular ligament was observed and noted on followup imaging. Relevant clinical notes for each patient were reviewed to follow their outcomes. The height of ankle injury was also assessed in patients with relevant MRI.

Nine patients showed ossification of the posterior tibiofibular ligament on followup imaging in which initial radiographs did not suggest injury. The ankle injuries were reclassified using the Lauge-Hansen Classification system.

Ossification of the posterior tibiofibular ligament implies injury to the ligament and reclassifies traumatic ankle injury from a low to high sprain. A syndesmotic injury is a poor predictor of early return to sport. Early recognition of this injury and reclassification of the ankle sprain leads to appropriate timely treatment. It is likely that calcification occurs early enough that it may be used to guide appropriate rehabilitation.

Syndesmotic injuries are underdiagnosed and identification of early signs of this injury, such as ossification of the posterior tibiofibular ligament, may aid in accurate diagnosis and treatment.

Tuan, A, Hughes, T, Hindsight Is 20/20: Ossification of the Posterior Tibiofibular Ligament on Follow-up Ankle Radiographs Reclassifies Traumatic Ankle Injury from a Low to High Sprain.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034287.html