bone repair Flashcards
how bones break
repetitive force single force - load - rate - direction - bone properties - soft-tissue forces
classifications of fractures
broken fractured cracker/hairline greenstick buckle avulsion
’ a soft itssue injury complicated by a broken bone’
why classify?
Immortality Information sharing (#) Guide treatment Guide prognosis Research allow direct comparison
anatomical, mechanism and descriptive classification of a fracture
Anatomical Proximal, Mid, Distal Intra/extra-articular Displaced/Undisplaced Open/closed Simple/Multifragmentary Mechanism of injury Bending Shearing Compression Rotation Comprehensive (descriptive) AO Muller
displacement
S hortening- distance
T ranslation- %
A ngulation- degrees
R otation- degrees
diagnosis and imaging
History - mechnism Examination look Feel Move Investigations Xray USS CT MRI
XRays
2D representation of 3D structure Rule of 2s 2 views AP and Lateral 2 Joints Above and Below 2 Times Before and After
ultrasound scan USS
Haematoma
Joint effusion
Tendon/Vascular injury
CT
3D reconstruction
Joint surface
Comminution
Angiogram
MRI
Associated injuries Ligament Cartilage Tendon Occult fractures Stress fracture The “dreaded black line”
treatment principles
4 Rs Resuscitate Re-align Joint surface anatomical Restrict Minimise further soft tissue damage Stable biological fixation Rehabilitate Early weight bearing
bone healing
How do I want this to heal? Primary Secondary (with callus) Adjuncts Osteo conductive Osteo inductive Osteo genic
How should I fix this?
Absolute stability
Relative stability
perren’s Strain theory
Perren’s Strain Theory
Amount of fracture movement relative to fracture gap
Different tissues tolerate different amounts of movement
Up to 100% - Granulation tissue
Up to 17% - Fibrous Connective tissue
2-10% - Fibrocartilage
< 2% - Bone
Within range for bone
fracture ends resorbed
strain reduced
leads to differentiation of callus
Above threshold bone forming
process impaired
leads to non-union
principles of fixation
Manipulation Restore Length Rotation Stability Articular surface
treatment options
Non-surgical Analgesia Cast/splint/sling Surgical Internal fixation K-wires Plate/screws Intramedullary nail External fixation
external fixation
temporary procedure
correction of deformity
LC-DCP
allows linear compression across fracture gap .
footprint on bone reduced ~ 50%
minimises periosteal compression
compression plate biomechanics
Fracture reduced to plate Relies on large friction forces Rigid fixation / absolute stability Direct healing with no callus Prone to failure
locking plate
Angular and Axial Stability
Flexible Internal Fixation
Fixed angle construct
locking plate biomechanics
Surrogate cortex
Angular and Axial stability
No friction (Bone/Plate) required
Periosteal blood flow unrestricted
Flexible elastic fixation with fragments splinted (Biological fixation)
Indirect Healing similar to external splinting Ex-fix and IM devices
Load shared across each bone/screw interface
Cut-out of screws is now or nothing
LCP
Combination Holes
Linear compression
Angular and axial stability
IM nail
Minimise soft tissue injury
Only available for certain fractures
what influences fracture healing
Injury factors Energy Environment Patient factors Compliance Comorbidities Surgical factors Suitability Stability
fracture complications
Immediate Haemorrhage Short term Compartment syndrome Neurological injury Fat embolus Mid term Infection Delayed/non-union Long term Loss of function Growth disturbance Arthritis
