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

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

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

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

Indications Deformity Correction Congenital Post-traumatic Acquired

Indications Reconstruction Arthrodesis Malunion Nonunion Infection

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

External Fixation Constructs Uniplanar Biplanar Circular (Ilizarov) Hybrid

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

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

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

Stability Factors Pin/Wire Location Maximal pin span

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

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

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

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

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

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

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

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

Compression External Fixators Arthrodesis in the setting of infection

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

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