scaphoid fixation iliac crest vs distal radius bone graft a biomechanical study vera kinzel paul...
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Scaphoid Fixation Iliac Crest vs Distal Radius Bone Graft
A Biomechanical Study
Vera Kinzel
Paul Jarrett
Karl Stoffel
Fremantle Hospital,WA
Introduction
Most common fracture of carpus
Displaced fractures/Non-unions:- require ORIF - +/- bone grafting
Common graft sites-Distal radius-Iliac crest
Introduction
lliac crest:
-most common source of bone graft-better quality of osteoprogenitor cells-better biomechanical properties-accurately restore shape and size of s.-higher donor site morbidity-long incision-painful donor site
Introduction
Distal radius graft:
-no perceptible co-morbidities-easy to shape-increasing skin incision by just 2 cm-vascularised bone graft
Aim
Biomechanical properties of scaphoid fractures with different bone grafts
Guide future clinical practise
Establish scaphoid morphology
Methods
Fresh frozen cadaver wrist:- 14 paired wrist- 28 scaphoids - thawed to room temperature 12 hours prior to testing- soft tissue removed- leaving scaphoid and cartilage intact
Methods
Photographed
Methods
Weighted
Measured
Methods
CT
Methods
CT
Methods
DEXA bone desitometry
Methods
Osteotomy-5 mm midwaist-custom made jig
Methods
Paired scaphoids
-Randomised left /right
iliac crest or distal radius corticocancelleous grafts
Cannulated compression screw (Titanium miniAcutrek® screw, Acumed)
Methods
Methods
Methods
Methods
Post Grafting
Methods
Scaphoid was cemented into standard nut
Orientated to scaphoid axis
Placed into material testing machine(Zwick Z010, Test-Expert-Software Zwick, Inc., Ulm,
Germany)
Methods
Testing:- Gradual loading- Assessment of load to failure
Data:- Load to 2 mm displacement - Load to failure- Moment at 2 mm displacement - Moment at failure- Stiffness
Methods
Methods
Methods
Methods
Methods
Methods
Statistics
Significance paired Students’ t-test
Statistical significance accepted at 0.05 level
Results
Morphology:
Weight: 4.57 gVolume: 2413 mm3
Density: 0.39 g/cm2
Height: 11.4 mmLength: 29.3 mmWidth Waist 13.7 mm
Results
Morphology:
Many features vary considerablyBasic shape similar
Significant difference- Dimension- Density
Results
Load 2 mm displacement
Load at 2 mm Displacement Run 1
0
50
100
150
200
250
Radial Graft
Iliacal Crest Graft
Results
Load at failure
Load at Failure
0
50
100
150
200
250
300
Radial Graft
Iliacal Crest Graft
Results
Moment at 2 mm
Moment at 2 mm Displacement
0
0.5
1
1.5
2
2.5
Left
Right
Results
Moment at Failure
Moment at Failure
0
0.5
1
1.5
2
2.5
3
Left
Right
Results
Stiffness
Stiffness
0
50
100
150
200
250
300
350
Series1
Series2
Summary
No significant difference inbiomechanical testing between Iliac crest and distal radius bone graft
Discussion
Insufficient literature on different grafts
Iliac crest and distal radius provide grafts - suitable size/shape
Iliac crest:- creates closer morphology
Discussion
Biomechanical properties similar Distal radius source of less donor site
morbidity
Discussion
Limitation of study:-Ex vivo study-No conclusion on:
- Osteoprogenitor cells- healing
cadaver bone-unknown handedness- most likely elderly donors- ? differences to actual fracture population
Thank you
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