Objectives: To assess the medium-term functional and radiological outcomes, as well as injury mechanisms, fracture patterns and demographics of typical pilon fractures and pilon variant fractures treated based on the four-column theory in adults.
Methods: A retrospective comparative study was performed. Demographics of typical pilon and pilon variant fractures, injury mechanisms, OTA/AO classification, Rüedi-Allgöwer and the four-column classification were analyzed for the cohort. Radiographic ankle arthrosis (modified Kellgren-Lawrence 3/4), Burwell Charnley Score, and AOFAS score were also analyzed.
Results: There were 142 pilon fractures met the inclusion and exclusion criteria for this study, of which 77(54.23%) were females and 65 (45.77%) were males, with an average of 48 (range, 18-86)years. One hundred twenty-five posterior columns fractured in 142 pilon fractures, and the posterior columns were most prone to fractures. Ninety cases of posterior pilon fractures in 142 pilon fractures were single posterior column fractures with or without medial or lateral malleolar fractures. The average age (51, range, 18-86 years) of low-energy pilon fractures was older than the average age (42, range, 19-66 years) of high-energy pilon fractures significantly. The average time (5, range, 0-17 days) from injury to definitive internal fixation of the low-energy group was shorter than the average time (9, range, 0-21 days) from injury to definitive internal fixation of the high-energy group significantly. The average of AOFAS (87, range, 56-100) of the low-energy group is higher than the average of AOFAS (82, range, 47-100) of the high-energy group significantly. There were more male patients and more die-punch or intercalary fractures in high energy groups significantly. There were more medial and lateral malleolar fractures in low-energy groups. Compared with the non-multiple column group, the multiple-column group had more Rüedi-Allgöwer type III cases, more modified Kellgren-Lawrence 3/4 cases and lower AOFAS score significantly. However, the numbers of Burwell Charnley Score type 1 and 2 cases were not significantly different between the two groups.
Conclusions: Kinds of pilon variants should be recognized. Outcomes of high-energy pilon fractures were worse than low-energy pilon fractures. The four-column theory can be applied to typical pilon fracture and pilon variants in adults.
Keywords: Classification; Outcome; Pilon variant; Tibial pilon fracture.
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