1. Module #13 Brian C Toolan, MD Shepard Hurwitz, MD Basic Techniques in External Fixation Developed by the Surgical Skills Task Force of the American Board of Orthopaedic Surgery (ABOS) in collaboration with the American Academy of Orthopaedic Surgeons (AAOS), and the American Orthopaedic Association (AOA)/Council of Orthopaedic Residency Directors (CORD) Presentation #1: Indications and Biomechanics

2. Basic Motor Skills External Fixation Indications & Biomechanics Brian C Toolan MD Shepard Hurwitz MD

3. External Fixation Operative technique for bony realignment and stabilization in trauma and reconstruction Fractures Limb deformity correction Arthrodesis

4. Indications Trauma Open Fractures Severe soft tissue injury Comminution Bone loss Temporizing or Definitive means of fixation

5. Indications Deformity Correction Congenital Post-traumatic Acquired

6. Indications Reconstruction Arthrodesis Malunion Nonunion Infection

7. External Fixation Constructs use pins and/or wires connected by clamps to bars and/or rings Constructs used to apply compression, distraction or neutral forces on bone

8. External Fixation Constructs Uniplanar Biplanar Circular (Ilizarov) Hybrid

9. Advantages Simplicity and ease of application Minimal blood loss Adjustability after surgery Access for wound management

10. Disadvantages Anatomic structures at risk (Safe Zones) Pin/Wire site infections Joint contractures Prolonged time to bony healing

11. Safety Factors Pin/Wire should not be in the fracture When drilling go slow as not to burn the bone

12. Stability Factors Pin/Wire Location Maximal pin span

13. Stability Factors Pin/Wire Number More pins distribute forces and increase construct stiffness

14. Stability Factors Pin/Wire Size Torsional strength proportional to its radius 4 Pin core diameter < 1/3 bone diameter

15. Stability Factors Insertion Technique Thread-Shank junction is weakest point Insert pin shank to proximal cortex (2x increased stiffness) (threads = bone width) Off plane pin insertion

16. Stability Factors Insertion Technique Circular frames Wires placed at 90 o stiffer than at 45 o Increased wire tension stiffens circular frames

17. Stability Factors Pre-drilling Low-speed drilling reduces thermal necrosis HA coating increases pullout strength

18. Carbon Fiber Rods Carbon fiber rods stiffer than steel tubes Lightweight Radiolucent

19. Stability Factors Lower Bone-Rod distance increases stiffness In-line stacking increases stiffness Second sidebar at 90 o to first increases stiffness

20. Spanning External Fixators Portable Traction Span intra-articular fracture Aide reduction through ligamentotaxis

21. Compression External Fixators Arthrodesis in the setting of infection

22. Distraction External Fixators Limb Lengthening through Distraction Osteogenesis 1mm / day Multiplanar corrections

23. Module #13 Brian C Toolan, MD Shepard Hurwitz, MD Basic Techniques in External Fixation Developed by the Surgical Skills Task Force of the American Board of Orthopaedic Surgery (ABOS) in collaboration with the American Academy of Orthopaedic Surgeons (AAOS), and the American Orthopaedic Association (AOA)/Council of Orthopaedic Residency Directors (CORD) Presentation #1: Indications and Biomechanics