E1393. How to Fix a Fracture: Basic Concepts of Fracture Healing and Orthopedic Hardware
  1. Joshua Gu; McGovern Medical School
  2. Nicholas Beckmann; McGovern Medical School
Skeletal fractures are a very common pathology, and orthopedic fixation of these fractures is frequently performed. Fractures with orthopedic fixation are a pathology that all radiologists encounter during residency and many radiologists continue to encounter in their daily practice. However, most radiologists lack a basic knowledge of how fractures heal and how orthopedic hardware is designed to promote this healing process. This knowledge is important because understanding the healing process can help radiologists differentiate delayed healing and hardware complications from normal treatment changes as well as identify early evidence of hardware failure. This presentation aims to educate viewers on the healing process of bone and how orthopedic hardware is designed to promote this process.

Educational Goals / Teaching Points
1. Describe the process of primary and secondary fracture healing 2. Discuss how orthopedic hardware design can promote primary or secondary bone healing 3. Differentiate orthopedic constructs designed to promote primary healing from those promoting secondary healing 4. Recognize the normal appearance of primary and secondary fracture healing and the normal appearance of common fixation hardware 5. Identify early findings of hardware failure and delayed fracture healing

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
1. Fracture healing- Discussion of how primary and secondary fracture healing occur with line drawings to illustrate the healing process. Discussion will emphasize the difference in length of time for complete healing and degree of callus formation between the two types of healing and how these factors influence which type of healing is preferred based on fracture location. 2. Orthopedic hardware- Discussion of hardware in general terms with an emphasis on how the hardware design promotes primary or secondary healing. We will also include normal post-operative appearance of the hardware. Hardware to be discussed includes: • Screws- Lag (by design & by technique), rafting, blocking, inter-locking • Plates- Compression, locking, combination, neutralizing, buttress, malleable/reconstruction • Intramedullary nails/screws • Wiring- Tension band, cerclage, Kirschner 3. Demonstration of normal appearance of primary and secondary healing at different stages of the healing process. We will discuss how to define delayed union versus non-union, how to recognize different types of non-union (hypertrophic, oligotrophic, atrophic), and how those types of non-union are treated differently. 4. Fixation failure- Exhibit cases of non-healing fractures and hardware failure with an emphasis on the early findings of delayed union and hardware failure.

Imaging of fractures and fracture fixation is a significant component of musculoskeletal radiology. By reviewing this presentation, radiologists will have a better understanding of how fractures heal and how hardware promotes this process, which can improve a radiologist’s ability to differentiate normal fracture healing from early signs of hardware failure.