Objectives: To describe and investigate the injury pattern and outcomes of high-energy transsyndesmotic ankle fracture dislocations, or "Logsplitter" injuries, in which the talus is axially wedged into the tibiofibular joint. Design: Prospective Cohort Study. Setting: Level 1 trauma center. Patients: Prospective evaluation of 23 high-energy transsyndesmotic ankle fracture dislocations (OTA 44-B). Intervention: Operative fixation. Main Outcome Measurements: Radiographs, clinical examination, American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale, Short Musculoskeletal Function Assessment. Results: Fracture characteristics included 52% open fractures (all medial) and syndesmotic widening of 30.7 +/- 11.9 mm. The tibial plafond was involved in 11 (48%) of 23 injuries, with 5 (22%) Chaput, 5 (22%) posterior malleolar fragments, and 6 (26%) with articular impaction. A fibula fracture occurred in all but 1 patient, on average 64.2 +/- 40.0 mm above the distal tip. All patients had fixation of their fibular and medial malleolar fractures, 21 of 23 patients had syndesmotic screws, and 8 of 23 had tibial plafond fixation. Anatomic alignment (within <= 2 mm) was obtained in 21 (87%) of 23 injuries. Mean follow-up was 20.6 +/- 6.2 months. Sixteen (70%) of 23 patients had radiographic evidence of posttraumatic ankle arthritis. Dorsiflexion and plantarflexion at final follow-up were 6.9 +/- 9.6 and 35.6 +/- 12.1 degrees, respectively. Complications included a 17% infection and 17% nonunion rate. Average American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale score was 67.0 +/- 26.8, whereas Short Musculoskeletal Function Assessment Dysfunction index was 32.9 +/- 28.6 and Bother index 34.5 +/- 29.5. Conclusions: Transsyndesmotic ankle fracture dislocations, or "Logsplitter" injuries, represent an exceptional pattern of high-energy fractures with significant syndesmotic disruption, potential soft tissue compromise, and possible associated plafond injuries. Careful attention to radiographic findings can identify unique fracture characteristics relative to operative decision-making. Outcomes are comparable to those of high-energy pilon fractures, thereby providing the treating surgeon with prognostic information. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
