eccentrically on the calcaneus. Looking at it from the back, the talus lies medial to the center of the calcaneus, and thus it shears off the anteromedial piece. How far lateral that primary fracture line extends depends on the position of the foot and subtalar joint when the impact hits it.
Secondary Fracture Line(s) – runs through the posterolateral (tuberosity) fragment. Two distinct fracture patterns are seen depending on where this secondary fracture line exits – Tongue type or Joint depression. (Essex-Lopresti classification)
Tongue type – the secondary fracture line goes posteriorly from the crucial angle to the tuberosity, creating a large, posterior superior and lateral fragment, with a portion of the posterior facet on its anterior part.
Joint depression – the secondary fracture line goes posteriorly from the crucial angle but exits just back from the articular facet, creating a fragment separate from the tuberosity – the “thalamic portion” which contains a portion of the posterior facet.
– in either of these two types, the secondary fracture line creates a fragment that usually tips downwards, leaving a significant sagittal incongruity in the subtalar joint
– the magnitude of the injury is what causes the comminution of the tuberosity fragment; it is in this fragment that the secondary fracture line is created, and more energy creates more fracture lines and comminution, often blowing out the lateral wall, and extending anteriorly to the calcaneocuboid joint.
– severe claw-toe deformities can result from these
– need to review the articles from Myerson and Manoli to figure out what it is that they are decompressing.
– Nonoperative – no need to immobilize – these heal just fine. Early ROM
– Operative – the full Monty – extensile lateral approach with rigid fixation, bone graft
– L shaped incision behind the sural nerve; large skin/soft tissue flap elevated. Take down the calcaneofibular ligament, peroneal tendons, elevate them anteriorly
– the degree of subtalar incongruity is the most important prognostic facteor
– decrease in Bohler’s angle is important, but not as much as the subtalar incongruity; a decrease to -0o or less has been associated with poor results.