ankle fracture orif - american podiatric medical association power point for apma updated.pdfankle...
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Ankle Fracture ORIFGetting Back to the Principles
Dr. Javan S. Bass, FACFAS
Metro Foot & Ankle Centers, PC
Georgia Podiatric Association Board of Directors
No Disclosures
Why Bother?
Questions
- How many locked screws are needed to improve fixation
- Where should locked screws be placed for biomechanical adv.
- What is the effect of each additional locked screw
- How locked screws affect hybrid plate fatigue properties
-Appropriate plate length and screw density
Hybrid Plating
- Locked plating (single beam construct)
secondary bone healing
- Rigidity up to 4 x’s greater than intact bone
- Non-Lock plating relies on friction (plate/bone)
primary bone healing
- 3-5 Nm of torque needed unobtainable in
osteoporotic bone
Gautier et al, INJURY March 2000
Hybrid Plating
Freeman et al, J Orthop Trauma March 2010
- Stiffness
-33% increase from 3 to 4
screws (row 3)
- addt. 34% increase when
increasing to 3 locked screw (row 7)
-addt. Screws allowed for
smaller % reductions in stiffness
over the cycle loading period
Freeman et al, J Orthop Trauma March 2010
Removal Torque
- same for locked screws
- Non-lock screw removal
torque increased by 274%
when farthest from fracture
line and immediately distal to
locking screw
Freeman et al, J Orthop Trauma March 2010
Plate Ratio and Screw Density
Plate ratio is ratio
btw plate length and
fracture length
-(2/3:1) - complex frx’s
-(8/10-1) - simple frx’s
Increase working length
Decrease screw load
Gautier et al, Injury, Int J. Care Injured 2003
Plate Ratio and Screw Density
Screw density refers to
number of screws
occupying holes within
the plate
- 0.5 when possible
Decreased screw density
allows for decreased bending
moments
Gautier et al, Injury, Int J. Care Injured 2003
Increased Bending Moments
MVA
Why Bother?
Metro Foot and Ankle Centers, P.C
Metrofootanklepc.com
770-484-9599