VCOM Louisiana Research Day Program

Clinical & Case Studies

Michael Osmun, OMS-III; Jacob Turnbull, DO; Kristina Zarenko, PhD; Colleen Cheverko, PhD; Jeffrey Counts, DO Edward Via College of Osteopathic Medicine 24 CREATING AND EVALUATING AN IATROGENIC ADDUCTION ANKLE FRACTURE IN A FORMALIN EMBALMED CADAVER

Introduction: Ankle fractures are common, with an incidence rate of approximately 168.7/100,000 adults per year [2] . Adjusting for today’s current population produces 561,354 fractures per year in the United States [4] . Literature suggests that 3% of those fractures will be classified as Weber Type A fractures, 70% as Type B, and 27% as Type C. Ankle fractures created in cadavers can be a useful teaching tool for medical learners. Most studies demonstrating cadaveric fractures involve producing a synthetic open fracture using a variety of tools such as osteotomes and mallets [1, 5] . While this technique appropriately produces the desired fracture, it also damages the overlying skin and soft tissue creating an open fracture, which is clinically less common. The goal of this cadaver case is to create a common ankle fracture using external force and to evaluate the surrounding soft tissue through dissection to see if embalmed tissue responds similarly to live tissue given the injury according to the Lauge Hanson classification system. Methods: Using a formalin-embalmed cadaver, a large adduction force was applied to the distal 1/3 tibia, while assistants stabilized the proximal tibia to prevent external/internal rotation. The fracture was confirmed with ultrasound and x-ray. The lower leg and ankle joint were then

dissected while evaluating for any injury to the surrounding soft tissue. Once all the major tissues were exposed, the fracture was repaired by an open reduction internal fixation procedure. Results: The force applied resulted in an oblique fracture of the distal fibula and distal tibia. Ultrasound and x-ray imaging confirmed the diagnosis and provided clear pictures of the injury. The imaging modalities revealed a Weber Type C fracture according to the Danis Weber classification scale. Dissection of the cadaveric leg confirmed the fracture pattern and revealed a small portion of the interosseous membrane was injured at the same level as the fracture. Otherwise, the tibiotalar joint was unaffected, along with its associated ligaments, tendons and muscle. Discussion: Conclusion of this experiment demonstrated that it is feasible to induce a closed fracture in a formalin-embalmed cadaver. The results also gave insight on how a cadaveric specimen will react to an excessive adduction force applied above the ankle compared to that of a living human specimen. We hypothesized that the cadaveric tissue stiffness would result in multiple soft tissue injuries, including muscle rupture and interosseous disruption, but upon dissection of this case, that hypothesis

did not prove to be true. Cadaveric tissue was more pliable than originally thought, and as mentioned, we noticed very little soft tissue injury. According to the Lauge Hansen classification system, Weber C type injuries are typically seen with pronation-abduction, and pronation-external rotation forces [3] . The injuries expected with these forces consists of not only spiral or oblique fracture of the fibula and fracture of the medial malleolus, but also rupture of the deltoid ligament which could involve avulsion of the medial malleolus, injury to the anterior inferior tibiofibular ligament, and injury to the posterior inferior tibiofibular ligament [3] . A method of inducing an isolated fracture without soft tissue damage in a cadaver provides a unique educational experience, whether it be from physical exam/palpation, imaging modalities such as x-ray or ultrasound, or even open reduction internal fixation of a cadaveric synthetic fracture.

37 2023 Via Research Recognition Day