Review of the principles of fracture management AO

Review of the principles of fracture management AO Trauma Advanced Principles Course

Learning objectives • Explain principles of fracture fixation that will lead to early functional aftertreatment • Realize how correct reduction technique respects the soft-tissue envelope • Understand concepts of stability, effect on bone healing, and correct application of implants

Goal—restore normal function ASAP

Fracture healing • Stephan Perren’s strain theory (1978) • Tissue cannot form in a fracture gap if the strain is greater than yield tolerance for that tissue

Fracture healing

Fracture healing

Fracture healing

Fracture healing

Fracture healing

Fracture healing

Fracture healing

Fracture healing

Is anatomy crucial?

al ? i c u r c y Anatom Yes - ORIF No – choose implant

Anatomy is crucial • Precise reduction—usually open with visual confirmation • Absolute stability techniques with implants under tension (eg, lag screws, compression plates) • Low-strain environment • Healing by remodeling—no callus

Reduction techniques—direct Simple but may require extensive exposure and additional stripping

Reduction techniques—direct Proper open reduction minimizes surgical trauma and maintains bone viability

Open reduction with a plate

Open reduction with a plate

Absolute stability fixation relies on tensioned implants (preload) Tensioned implants are like the spokes of a wheel

Preloaded implants maintain forces of reduction and fixation

Lag screws create interfragmentary compression

Protection plate Screws are protected from pullout based on the forces of torsion and bending by protection (neutralization) plate

Protection plate

Compression plate • Compression can be generated by the plate under tension • Dynamic compression plate can generate interfragmentary compression

Compression plate • Tension in plate generated by articulated tension device • This generates interfragmentary compression Articulated tension device

Compression plate Overcontouring the plate will ensure compression at the far cortex

Alignment is crucial Ideal implant will: • Hold the joint-bearing segments in their correct anatomical relationship until the bone in between heals with callus • Lie as close as possible to mechanical axis—line connecting centers of rotation of joints at each end

New design intramedullary nails

New design intramedullary nails • Extend the nailable zone into the metaphysis • Special techniques for reduction, particularly when the fracture is close to entry point

Entry point troubles

Blocking and Poller screws

Reduction before nailing

Reduction with cerclage wires before nailing

Bridging plate Hold the joint bearing segments in their correct anatomical relationship until the bone in between heals

Bridging plate principles Stress distribution, near-far fixation

Minimal access techniques • Reduce surgical insult to traumatized soft tissues • Small incisions away from zone of injury • Less pain, faster rehabilitation • Technically demanding, requires sophisticated equipment

Minimal access principles Stable preliminary reduction

Minimal access principles Plate contouring

Minimal access principles Plate insertion

Minimal access principles Screw insertion sequence

Mixing techniques

Take-home messages • Anatomy is crucial – absolute stability – low strain – implants under tension – no callus • Alignment only – choose nail or bridging plate – moderate strain – healing with callus • Important to have a plan that makes sense and to execute that plan appropriately