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
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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.
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Module #13
Brian C Toolan, MDShepard 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 SkillsExternal Fixation
Indications & Biomechanics
Brian C Toolan MDShepard Hurwitz MD
External Fixation
Operative technique for bony realignment and stabilization in trauma and reconstruction
FracturesLimb deformity correction
Arthrodesis
Indications
TraumaOpen Fractures
Severe soft tissue injuryComminution
Bone loss
Temporizing or Definitive means of fixation
Indications
Deformity Correction
CongenitalPost-traumatic
Acquired
Indications
Reconstruction
ArthrodesisMalunionNonunionInfection
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 notbe 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 SizeTorsional strength
proportional to its radius4
Pin core diameter <
1/3 bone diameter
Stability FactorsInsertion Technique
Thread-Shank junctionis weakest point
Insert pin shank toproximal cortex
(2x increased stiffness)(threads = bone width)
Off plane pin insertion
Stability FactorsInsertion Technique
Circular frames
Wires placed at 90o stiffer than at 45o
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 FactorsLower Bone-Rod distance
increases stiffness
In-line stacking increases stiffness
Second sidebar at 90o 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 Lengtheningthrough
Distraction Osteogenesis
1mm / day
Multiplanar corrections
Module #13
Brian C Toolan, MDShepard 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)