Inducing a Closed Ankle Fracture in a Cadaveric Model to Create Interdisciplinary Teaching Models for Preclinical Medical Students

Abstract

This paper describes a cost-effective fracture simulation that aids in preclinical learning of fracture identification. This project establishes feasibility of inducing closed fractures in a donated cadaver. The study team made an identified Weber C ankle fracture in this donor, maintaining the soft tissue envelope surrounding the fracture, using minimal materials in a stepwise process that will be reproducible across educational programs regardless of access to highly specialized equipment. The resulting fracture can be used to help students identify fractures during their preclinical education and has demonstrated educational potential for future use and adaptation.

Background

Ankle fractures represent a common orthopedic injury that medical learners will encounter during training [1]. Ankle fractures accounted for 673,214 emergency department visits in the USA between 2012 and 2016 [1] for an incidence of 4.22/10,000 person-years during that period [1]. They are seen in a wide variety of patients and exhibit a bimodal age distribution, consisting of adolescent traumatic fractures and osteoporotic fragility fractures in the elderly [2, 3]. Learning to diagnose and manage ankle fractures is therefore an important clinical skill for medical learners to develop.

Often, the first hands-on experience for medical learners in the diagnosis and management of fractures is during clinical rotations involving a live patient [4, 5]. Malik-Tabassum et al. [6] surveyed 414 medical students in their final year of training and found the students reported low subjective competency in all areas of basic fracture care including collecting histories, performing physical examinations, interpreting images, and managing cases. Therefore, an opportunity to practice fracture diagnosis and imaging during preclinical coursework may be beneficial.

Current educational opportunities to learn the basics of diagnosing and treating fractures often use simulation models instead of donors, which can be complex and costly. Because evaluation and diagnosis are important foundations for medical learners at early stages of training, new ways of teaching medical students and residents need to be explored during curriculum development. Strong interdisciplinary collaborations between clinical and biomedical departments can aid in this development, allowing educators to combine resources available at institutions in pursuit of common educational goals.

The objective of this project is to describe a realistic fracture simulation model using a formalin-embalmed cadaveric donor as a case-based teaching tool for medical learners. This donor model provides meaningful but cost-effective training in the diagnosis and treatment of ankle fractures. Further, this model highlights how interdisciplinary pursuits strengthen early opportunities for medical learners.

Activity

Fracture creation, evaluation, and treatment occurred within the VCOM-Louisiana anatomy laboratory using a formalin-embalmed 56-year-old female donor with intact skin at the ankle free of wounds, ulcers, or abrasions; no observable history of ankle surgery; and a listed cause of death of pancreatic cancer with metastasis. Equipment used includes a four-inch Ortho-Glass (BSN Medical OG-4L2, Hamburg, Germany) splint, 12-inch bar clamp (Pony Jorgensen 3712-HD, Saddle Brook, NJ, USA), 24-inch metal pipe wrench, and ½-inch-thick wooden blocks. The following steps were taken to create a closed ankle fracture in this donor:

• Step 1: The donor was placed in a supine position, left knee fully extended and hip abducted to approximately 20 degrees. The ankle skin was protected to prevent visible marks denoting fracture location using two layers of athletic ankle pre-wrap followed by athletic tape over the malleolar zone. A U-shaped “stirrup” was molded semi-circumferentially around the medial and lateral malleoli using the Ortho-Glass splint (Fig. 1).

• Step 2: The bar clamp was secured to the wooden blocks over the lateral and medial tibial condyles at the tibiofemoral joint. Once fully tightened, the bar clamp was used as a handle to stabilize and prevent external rotation of the proximal tibia (Fig. 1).

• Step 3: The pipe wrench was fitted around the fiberglass stirrup approximately one-inch superior to the lateral and medial malleoli. The wrench’s handle was oriented perpendicular to the donor’s ankle and pointed laterally. Manual application of a varus force using the distal handle adducted the distal tibia and fibula and induced the fracture. An audible disruption of bone and obvious give of tissue was noted at time of fracture. All materials were then removed from the ankle to confirm lack of skin disruption.

• Step 4: A portable ultrasound (Butterfly iQ+, New York, NY, USA) was used to scan the tibia and fibula to identify the presence of cortical step-off indicating fracture. The fracture diagnosis was confirmed using anterior-posterior, lateral, and oblique views on portable X-ray (Ortho-San Mobile D1 Mini C-Arm CARM 11195-2857, Scottsdale, AZ, USA).

Fig. 1.

Fracture induction set up on donor. The left ankle of the donor was prepared with a layer of pre-wrap and 2-inch-wide athletic tape (a). Ortho-glass was molded to fit around the medial and lateral malleoli in the shape of a stirrup (b). The proximal tibia was stabilized using wooden blocks and a bar clamp (c). The pipe wrench was then secured approximately one inch above the malleoli with the handle oriented perpendicular to the limb (d)

In addition to these steps to induce and confirm the fracture, an orthopedic surgeon repaired the donor’s fracture using reduction clamps, drills, screws, and plates in a life-like surgical experience to further demonstrate advanced teaching uses of this model.

Results and Discussion

The method described above successfully induced a closed ankle fracture without damaging overlying skin. Mild compression of the superficial ankle was present due to protective wrapping but resolved over time. Ultrasound imaging revealed disruption of the distal fibular cortex. Radiographs demonstrate a transverse fracture of the distal tibia and an oblique fracture of the distal fibula (Fig. 2). The fracture was determined to be a Danis-Weber type C injury because the fibular component of the fracture was located proximal to the tibiofibular syndesmosis. Because Weber C injuries with syndesmotic involvement commonly necessitate surgical repair [3, 7, 8], the orthopedic surgeon repaired the donor’s fracture with assistance from a preclinical medical student (Fig. 3), further demonstrating feasibility for advanced uses and applications of this model in preclinical education.

Fig. 2.

Imaging confirmation of fracture. Ultrasound imaging of lateral malleolus in longitudinal (a) and transverse (b) views demonstrating step off pattern at the bony cortex representing the fracture site. Anterior-posterior (c) and lateral (d) radiographs of the ankle demonstrating a Danis-Weber C fracture

Fig. 3.

Results of surgical intervention. Photograph (a) and radiograph (b) of the orthopedic surgical intervention on the induced fracture

Experiential learning has been shown to enhance student learning, including hands-on clinical activities using anatomical resources [9, 10]. For example, Kuhls et al. [4] described how only 43.9% of participants in an advanced donor-based trauma surgery course for residents spent time in an anatomy laboratory following medical school, yet donor-based simulation courses allow residents to practice fundamental maneuvers and gain confidence in operative skills [11]. This protocol illustrates how faculty can introduce medical learners to the basics of fracture diagnosis using an anatomical donor model during their preclinical education and beyond.

Successful fracture diagnosis requires physical examination and imaging skills. Making an accurate diagnosis is important because missing ankle syndesmosis injuries in living patients can lead to increased morbidity [7]. Therefore, this opportunity is important because it allows the learner to gain experience examining, imaging, and forming treatment plans for patients with these types of fractures. Though the authors are focusing on this model’s use in preclinical education, its relevance could extend beyond medical students.

Beyond the benefits of integrating anatomical donors into clinical education, the teaching model presented here provides advancements to previously published studies. Some donor models have created fractures through open incisions and osteotomy on intact limbs [12]. Others recreated closed fractures but on disarticulated limbs [5, 13]. Open fractures create skin disruptions that make locating fractures easier. Closed fractures in disarticulated extremities work well for focal learning on specific body parts but disallow use of associated joints for learners to practice comprehensive physical examinations and differential diagnosis skills. The process to create closed fractures presented here maintains the soft tissue envelope surrounding the fracture site, making the diagnosis less obvious from initial visual examination and allowing better development of imaging skills.

This model could be improved in several ways. The mechanism of force was applied above the ankle mortise and did not include the ankle joint itself, making the mechanism of injury less realistic and limiting the applicable diagnostic systems to the Danis-Weber system to classify the resulting fracture [14]. Additionally, the force applied to the bone to create the desired fracture was not measured, but it has been successfully repeated on additional donors and joints with similar results. A DEXA scan was not performed on the donor so we cannot comment on the presence or absence of osteoporosis. It would be helpful in the future to study the above technique on donors with different bone quality and sex and age distributions to evaluate if the method is successful across all donors. Doing so would allow for maximum repeatability across programs adopting this educational model. Future studies should build upon existing literature (e.g., [4, 15]) to evaluate the validity of using our donor fracture model in preclinical medical education using standardized grading of the learner’s self-confidence, diagnostic accuracy, and procedural skills.

This project represents a successful design and implementation of a step-by-step method to induce a closed ankle fracture in a formalin-embalmed donor in the anatomy laboratory. Ankle fracture simulation has successfully been completed in previous studies that utilize highly specialized laboratory equipment and imaging technology [5, 9, 13], but to our knowledge we are the first to report a method for creating a closed fracture in an ankle using manual force and simple tools. As a result, this model allows for cost-effective reproducibility. This model can also be used and expanded upon for more widespread applications in preclinical and clinical curricula such as fracture identification and imaging workshops, hands-on practice of physical examinations, and fracture treatment. Medical education has been moving toward interdisciplinary approaches that emphasize experiential learning, and this project highlights how biomedical and clinical faculty can collaborate to produce an experiential learning model that incorporates skills and resources from multiple disciplines.

Author Contribution

Conceptualization: Jacob Turnbull; methodology: Jacob Turnbull, Kristina Zarenko, Colleen Cheverko; formal analysis and investigation: Jacob Turnbull, Kristina Zarenko, Colleen Cheverko, Michael Osmun, Jeffery Counts; writing—original draft preparation: Jacob Turnbull, Kristina Zarenko, Colleen Cheverko, Michael Osmun, Madison Blackwell; writing—review and editing: Jacob Turnbull, Kristina Zarenko, Colleen Cheverko, Michael Osmun, Madison Blackwell; resources: Jacob Turnbull, Kristina Zarenko, Colleen Cheverko, Jeffery Counts; supervision: Jacob Turnbull.

Data Availability

All data generated or analyzed during this study are included in this published article.

Declarations

Ethics Approval and Consent to Participate

This project was determined to be exempt by the Edward Via College of Osteopathic Medicine (VCOM) Institutional Review Board (IRB). The donor was used in the medical anatomy course. The donor donated their body to the University of Texas Southwestern (UTSW) Willed Body Program. Consent for anatomical dissection and research is obtained by UTSW as part of the donor application packet, and permission for education and research was obtained by the VCOM Division of Anatomical Sciences from the UTSW Willed Body Program.

Competing Interests

The authors declare no competing interests.