treatment of femoral neck fractures internal fixation –in biologic ‘young’ patients (<...
TRANSCRIPT
Treatment of femoral neck fractures
• INTERNAL FIXATION– In biologic ‘young’ patients (< 60-80 yr)
• ARTHROPLASTY – In biologic ‘old’ patients (> 60-80 yr)
Resultsof fixation of femoral neck fractures
35% RE-INTERVENTION RATE IN DISPLACED #• Non-union • Avascular necrosis • Loss of fixation
Fracture healingof femoral neck fractures
GOALS:• Preserve the remaining
blood supply• Provide the stability
necessary for revascularisation
• Provide the stability necessary for primary osteonal reconstruction
MEANS:• Anatomical reduction • Stable internal fixation
Why do implants fail?multiple parallel screws or pins:
PRO’S:• Dynamic• Minimal invasiveCON’S:• No angular stability• No rotational stability• Stability relies on the
three- point fixation method and is dependant on exact screw placement
• High total implant volume
Why do implants fail?sliding hip screw devices:
PRO’S:• Angular stability• DynamicCON’S:• No rotational stability
– During insertion – After insertion– With or without
‘anti-rotation’ screw• High implant volume
LABILE UNSTABLE
Can we make a better implant?
GANNET• Gannet nail & side wings• Impaction anchors• Gannet plate
CHARACTERISTICS:• Rotational stability• Angular stability• Dynamic compression• Impaction locking• Minimal invasive• High load bearing surface• Cannulated technique• Simple instrumentation
ROTATIONAL STABILITY:• Sidewings on blade• Impaction anchors
ANGULAR STABILITY:• Sliding barrel plate• Dynamic compression
IMPACTION LOCKING:Locking of the Gannet nail in the femoral head
1. Prevents perforation2. Prevents backing out3. Additional rotational stability4. Augmented by bone impaction
MINIMAL INVASIVELow implant volume:
• GANNET: 920 mm3
• DHS: 1975 mm3
MINIMAL INVASIVELow frontal area:• GANNET: 31 mm2
• DHS: 133 mm2
HIGH LOAD BEARING SURFACE:• GANNET: 338 mm2
• DHS: 221 mm2
CANNULATED:3.0 mm guide wire
SIMPLE INSTRUMENTATION
GANNET (DLBP)loading tests
GANNET (DLBP)static deformation test
ASTM F384-99 Static Loading Test
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2750
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Displacement (mm)
Forc
e (N
)
DHS_57
DLBP_57_BioDur108
GANNETfatigue test
Fatigue testDLBP, Biodur 108, Size: 100mm, free length: 63 mm
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10^3 Cycles
Fo
rce
(N
)
GANNETanchor expansion test
GANNETpush in test
GANNET (DLBP)cut out test
GANNET (DLBP)rotation test
Guide pin insertion
Stepped cannulated drilling
Introducer setting
Introducer/implant assembly
One step insertion
GANNET pilot study
• No technical complications• No general complications• Fracture healing 23/25• Avascular necrosis 1/25• Non union 1/25
GANNET pilot study
REINTERVENTION RATE : 2/25• Undisplaced fractures (n=8) : 0/8• Displaced fractures (n=17) : 2/17
GANNET conclusions
• Fast• Streamlined• Targeted • Fold wings in
pursuit
