SLR - April 2014 - Corine L. Creech
Reference: Cole PA, Mehrle RK, Bhandari M, Zlowodzki M. "The Pilon Map: Fracture Lines and Comminution Zones in OTA/AO Type 43C3 Pilon Fractures." Journal of Orthopaedic Trauma 27.7 (2013): e152-e156.
Scientific Literature Review
Reviewed By: Corine L. Creech, DPM
Residency Program: Temple University Hospital
Podiatric Relevance: Pilon fractures are devastating lower extremity injuries that require in-depth understanding and surgical planning. Fracture patterns with high degrees of comminution, the most complex being OTA/AO type 43C3 fractures, are especially difficult to treat. Identification of predictable fracture patterns and zones of comminution make preoperative planning more efficient, and could potentially make surgical intervention more successful.
Methods: The CT scans of 38 consecutive OTA/AO 43C3 fractures were obtained after the application of a spanning external fixator. Axial cuts approximately 3 mm superior to the distal tibial subchondral surface was selected for fracture mapping. Each image was then subsequently enlarged to correspond to a digital grid, in an attempt to standardize the injuries. Common fracture patterns were identified by superimposing the grid onto a “heat map” of the plafond to create a frequency diagram based on fracture line density. Zones of comminution were identified in a similar fashion.
Results: Consistent fracture lines were identified and were termed “major fracture lines”. These major fracture lines involved the tibiofibular joint in all cases. Fracture lines were noted to exit both anteriorly and posteriorly to the medial malleolus, forming a Y-shaped pattern. Three main fragments were identified in every case. All other fracture lines outside of this Y-shaped pattern were labeled as minor fracture lines, and were noted to be more variable. A single major area of comminution was identified located within the middle 1/3 of the plafond. A high incidence of comminution within the anterolateral ¼ of the tibial plafond was also identified.
Conclusions: This study was able to provide further insight into pilon fracture line morphology. Although at first glance, OTA/AO type 43C3 fractures appear to be extremely variable, this study was able to identify three consistent main fragments, and two possible zones of comminution. This information is extremely valuable for surgical planning, both for incision placement and hardware selection.