plating Flashcards
Biological osteosynthesis principle
bridging plate in multifragmentary diaphyseal fracture
- intermediate fragments untouched
- restores length rotation and angulation
- respects biology of fracture
Why leave several holes of bridging plate empty
less stress at each hole
Impact of sustained pressure on bone
if sustained and not excessive, may lead to osteogenesis
Impact of intermittent pressure on bone
bone erosion
Factors affecting stiffness and stability of ex fix
- shorter distance of rods from bones (the closer to skin, the more stiff)
- number of tubes (the more the more stiff)
- the separation of tubes on the same pins (the further away the parallel rods from each other, the better)
- the number of pins (the more pins the better)
- The wider the pins are separated in each fragment the stiffer the construct
- the closer the pins to the fracture site, the stiffer the construct
- system configuration
System configs for ex fix
Stainless teel or titanium stiffness
Titanium
- less stiff
- susceptible to weakening if pierced by holes or abraided during insertion
Solid vs hollow nails
Solid:
- more stiff
- cannot adapt to curvature mismatch between nail and bone
Hollow:
- provides environment for bacteria to proliferate inside
Factors affecting nail stiffness
- material
- solid or hollow
- slotted or unslotted
- diameter
- thickness of the wall
Tscherne classification of soft tissue injury
Significance of red blisters in fractures
indicates deeper dermal injury
When are blisters overlying fractures safe to operate on
Clear: 3-7 days
haemorrhagic: 10-14 days
What is wrinkle test
squeezing skin over fracture, if wrinkles appear, swelling has settled and safer to operate
What is wrinkle test
squeezing skin over fracture, if wrinkles appear, swelling has settled and safer to operate
Compartment syndrome immediate mx
Release circumferential dressing
Limb at heart level
Re-assess in 30 mins
Open fracture immediate management
- gross debridement
- abx
- pictures
- splint
Which open fractures need immediate operative mx
Vascular compromise
Sewage/farm injury
polytrauma
What to do with bony fragments in open fracture
If you can easily remove them (tug test) that means it was devitalised anyway
Guistillo-anderson classification
When can you consider internal fixation in trauma
if no contamination
And wound could be closed or covered
Plates function and their related stability (absolute vs relative)
Absolute:
- neutralisation
- buttress
- compression
- tenson band
Relative: bridging
Function of lag screw technique
Compression of fracture site
Which forces does the lag screw technique not protect against
Shear
Banding
Torsion
Axial loading
Where are tension band wiring used
olecranon
patella
Types of pin used in ex fix
Parallel threaded (good fit, no preload)
Slightly threaded (certain preload)
Markedly threaded (greater radial preload, microfractures at pin-bone interface)
What is the working length of a nail
Distance between the 2 locked parts of a nail
The longer the working length, the easier for it to bend
Positive impacts of reaming before nail insertion
Creates more space, to allow nail insertion
Damages the endosteal bloodsupply, stimulating the periosteal blood supply to increase aiding cortical healing
Negative impact of reaming before nail insertion
burns the bone
Ideal tip apex distance in DHS (
<25mm
AO proximal femur A, B, C classification
A- extracapsular
B- neck
C- head
Trochanteric fractures A1-A3
Mx of A1 proximal femur #
DHS
Why is hip shortened and externally rotated in femoral #
Unopposed pull of ileo-psoas muscle (flexion and ext rotation)
Mx of A2 proximal femur #
Depends on stability
- reverse oblique
- loss of calcar buttress
IM nail or DHS
Mx of A3 proximal femoral #
IM nail
Pauwels’ classification
For intracapsular fractures:
The more vertical, the more unstable
AO intracapsular fracture classification
B1 - subcapital , minimally discplaced
B2 - transcervical
B3- Subcapital, displaced.
Position of casting for distal radius fractures
Neutral flexion
Not palmar flexion (risk of median nerve compression)
3 point fixation:
- dorsum distal radius
- mid forearm on the volar side
- proximal point
How long does it take for 4 stages of bone healing
Non-op mx of distal radius fracture
Cast 4 wks
Consider removing cast and starting mobilisation after
Reasons for considerations of operative mx of distal radius fracture
- radial shortening
- radiocarpal alignment
- angulation (excessive dorsal or volar)
- loss of radial height (distance between radial styloid and radial-carpal articular surface)
Radial shortening in distal radius #
Causes relative ulnar lengthening and ulnar-carpal impaction
What is radiocarpal mal-alignment in the context of distal radius fracture
Distal radius falls into extension -> Loss of radio-carpal co-linearity -> adaptive midcarpal flexion (to allow hand function longitudinal to forearm)
Results in stiffness and pain
Surgical options of distal radius fracture fixation
K wires vs volar locking plates
- similar outcome, but k wire cheaper and quicker to perform (also better for soft tissue)
- K wire has risk of pin site infection
What 3 features of diaphyseal bone fractures need to be restored before fixation
Length
Alignment
Rotation
3 connections between Ulna and radius
Distal radioulnar joint: triangular fibrocartilage complex (TFCC)
Interosseus membrane
Proximal radioulnar joint: Radial head (annular ligament)
Montegia fracture description
proximal ulnar fracture with radial head dislocation
Montegia fracture mx
plate ulna
reduce radial head
Galeazzi fracture description
Distal radius fracture
associated distal radio-ulnar joint dislocation
Galeazzi fracture mx
Plate the radius and radio-ulnar joint should reduce
But if it doesnt, you could reduce and hold with k wires until it heals, needs to be in plaster as if patient pronates, it will break the wires
Galeazzi fracture mx
Plate the radius and radio-ulnar joint should reduce
But if it doesnt, you could reduce and hold with k wires until it heals, needs to be in plaster as if patient pronates, it will break the wires
Indications of fixation of forearm fractures
open fractures
both bone fractures
displaced single bone fracture
Monteggia or Galeazzi
Which forearm single bone fractures are fixed non operatively
Undisplaced
<10 degrees angulation
<50% displacement
Importance of the shape of talus in ankle fracture fixation
Anterior part is wider than posterior
Ankle is a mortise joint with talus slotting into the medial/lateral mal gap
Fixating the foot in dorsiflexion allows the widest part of the talus inserting in, achieving a much higher stability
Importance of the shape of talus in ankle fracture fixation
Anterior part is wider than posterior
Ankle is a mortise joint with talus slotting into the medial/lateral mal gap
Fixating the foot in dorsiflexion allows the widest part of the talus inserting in, achieving a much higher stability
Medial ligaments of ankle joint
Tibionavicular
Tibiocalcaneal
Posterior tibiotalar
Lateral colateral ligaments of ankle joint
Anterior tib fib
Anterior talofibular
Calcaneoufibular
Posterior ligaments of ankle joint
posterior tibiofibular ligament
Classification of pelvic fractures
