External Fixation Techniques

Module Overview

• Title: Basic Techniques in External Fixation

• Creators: Brian C Toolan, MD; Shepard Hurwitz, MD

• Developed by: 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 Focus: Indications and Biomechanics

Presentation Slides Overview

• Slide 1: Introduction to External Fixation

• Slide 2: Basic Motor Skills in External Fixation

• Slide 3: Overview of External Fixation techniques

External Fixation Techniques

Operative Techniques

• Bony realignment and stabilization

• Indications: Trauma and reconstruction

  • Trauma: Management of fractures

  • Reconstruction: Treatment for limb deformity

  • Arthrodesis: Joint fusion to stabilize painful joints

Indications for External Fixation

Trauma

• Open Fractures: Fractures where bone pierces through the skin

• Severe Soft Tissue Injury: Additional challenges in management

• Comminution: Fractures with multiple fragments

• Bone Loss: Significant compromise in bony structure

• Temporizing or Definitive Fixation: Use as an immediate or permanent solution

Deformity Correction

• Congenital Issues: Conditions present at birth

• Post-Traumatic: Deformities developing after injury

• Acquired: Deformities arising from previous conditions or treatments

Reconstruction

• Arthrodesis: Fusing bones across a joint for stability

• Malunion: Incorrect healing of broken bones

• Nonunion: Failure of fracture to heal adequately

• Infection: Managing infected fractures or sites

External Fixation Constructs

• Components: Use of pins/wires connected with clamps to rigid bars/rings

• Purpose: Apply compression, distraction, or neutral forces on bones

Types of Construct

• Uniplanar: Single plane configuration

• Biplanar: Two planes for increased stabilization

• Circular (Ilizarov): Allows for complex deformity corrections

• Hybrid: Combines different fixation elements for optimization

Advantages of External Fixation

• Simplicity & Ease of Application: Rapid setup in acute situations

• Minimal Blood Loss: Less invasive compared to other methods

• Adjustability Post-Surgery: Allows for modifications after placement

• Access for Wound Management: Enables hygiene and treatment without removal

Disadvantages of External Fixation

• Anatomical Risks: Need to be aware of surrounding structures (Safe Zones)

• Pin/Wire Site Infections: Risk factor in external fixation procedures

• Joint Contractures: Possible stiffness arising from prolonged application

• Prolonged Healing Times: Delays in bony healing can occur

Safety Factors in External Fixation

• Pin/Wire Placement: Avoid insertion within the fracture site

• Drilling Technique: Slow speeds recommended to prevent thermal damage to bone

Stability Factors

Pin/Wire Location

• Optimal placement technique for stability

Maximal Pin Span

• Span between pins influences overall stability

Number of Pins/Wires

• WILH Principle: More pins lead to better distribution of forces and enhanced construct stiffness

Pin/Wire Size

• Torsional Strength: Stronger with increased radius, optimal diameter is less than 1/3 of bone diameter

Insertion Technique

• Placement techniques critical to ensure stability, including the conditions of the thread-shank junction and using the proximal cortex for insertion

Circular Frames

• Wires at 90 degrees offer better stiffness than at 45 degrees

• Increased wire tension enhances the stability of circular frames

Pre-Drilling Advice

• Low-speed drilling recommended to reduce heat and enhance outcomes, HA coating can improve pull-out strength

Material Considerations

Carbon Fiber Rods

• Advantages: Stiffer than steel, lightweight, and radiolucent for imaging

Structural Considerations

• Bone-Rod Distance: Closer distances increase stiffness

• In-Line Stacking: Stacking rods in-line improves stability

• Cross Stacking: Additional rods placed at 90° to primary rods enhance strength further.

Application Types of External Fixators

Spanning External Fixators

• Portable Traction: Provides reduction options for fractures

• Ligamentotaxis: Utilizes biological tissue traction for fracture reduction

Compression External Fixators

• Used for:

  • Managing infections in arthrodesis cases

Distraction External Fixators

• Limb Lengthening: Achieved through distraction osteogenesis, typically at a rate of 1mm per day

• Capable of performing multiplanar corrections

Presentation Conclusion

• Overview of external fixation's indications and biomechanical principles.