Fracture Mechanics Flashcards
Bone Properties
Capacity to regenerate
Remodel in response to stress (Wolff’s Law)
Forces on fractures
Tension, compression, shear, bending, torsion
Strength of bone dependent on
Material properties, structural, orientation of load applied, rate of load applied
Increased kinetic energy
trash the soft tissues too
Incomplete fractures
Greenstick, fissure and depression fractures. No displacement of bone
Complete fractures
Transverse, oblique, spiral, comminuted, segmental, and compression fractures
Transverse fractures
Result of bending forces
Oblique fractures
Bending and axial forces
Spiral fractures
Torsional forces
Segmental fractures
Fractures lines to not communicate
Comminuted
Result of high energy trauma
Type 1 fracture
Clean soft tissue laceration of <1cm
Type 2 fracture
Soft tissue laceration of >1cm; mild trauma. No flaps or avulsion
Type 3a Fracture
Soft tissue available for wound coverage despite vast laceration. Flaps or high energy trauma
Type 3b Fracture
Extensive soft tissue injury loss, periosteum stripped and bone exposed
Type 3c Fracture
Arterial supple to the distal limb damaged, arterial repair indicated
Fracture etiology extrinsic forces v intrinsic
direct v indirect
Physiologic, pathologic, stress
Describing fractures
Open or closed, configuration, location, right or left, bone, displacement
Secondary bone healing
Inflammatory phase, reparative phase, remodeling phase. Strength dependent on callus formation
Granulation to fibrocartilage to bone
Primary bone healing
Requires rigid fixation. Associated with minimal callus formation. Contact healing: direct apposition. Gap healing: gaps <1mm
Fracture healing
Dependent on age of animal and location and type of fracture. Callus expected to be evident in 2-4 weeks. Fracture line may initially widen. Fracture segments and fragments remodel
Accelerate healing
Reduce better.
Bone graft- greater trochanter- humerous
Osteogenic direct, osteoinduction, osteoconduction
