Pfn biomechanics

How PFN scores over DHS for inter trochanteric fractures.

1. Cephalomedullary Nailings Cephalomedullary Nailings
(PFN / TFN)(PFN / TFN)
In Unstable Inter Trochanteric Fractures In Unstable Inter Trochanteric Fractures
And its Biomechanical ConsiderationsAnd its Biomechanical ConsiderationsDr. B. Shivashankar.Dr. B. Shivashankar.
SolapurSolapur


ISO 9001:2008
Certified
Hospital

2. Stable
Easy to treat by any method
Un Stable
DIffficult to treat
Simpler Classification For Surgeon
If lateral wall is intact and lesser trochanter is intact it is stable,
if any one of them is broken it is unstable

3. Gradual # CollapseGradual # Collapse
Barrel allows the screw to slide gradually during the course of fracture healing

4. Intact Lateral wall – Key for determining outcome

5. Pre Operative Day 1
31. A2.1 31. A3. 3
31% of A2 Type Fractures

6. Day 40 Day 70

7. IM implant : acts as a buttress to
prevent excessive # collapse and
shaft medialization

8. Outcome of Sliding Hip Screw in Un Stable Fractures
Is DHS still the Gold Standard?
Thanks : Dr.Anil Kharkanis for some pictures in this slide

9. DHS Improvements 1985-1999
To Prevent To Prevent
Medialisation – T S PMedialisation – T S P

10. Slide Courtesy: Indiaorth

11. Dynamisation along ShaftDynamisation along Shaft
Medoff plate also requires an intact lateral wall
Otherwise too much medialisation happens as show here

12. PFN= DHS+TSP+Medoff Plate
Plus Intra Medullary implant!
•DHS
•1. Screw Slides in Barrel
•2. TSP added can prevent
medialisation
•3. Along with Medoff Plate
can have collapse in the
shaft useful for ST#s
•4. Adding Derotational
screw increases stability by
preventing spinning of head
•PFN
•1. Screw slides in Nail like DHS
•2. Expanded proximal portion
of nail abuts and works as TSP
and prevents medialisation
•3. Dynamic distal locking done
will lead to axial nail
subsidence and works as
Medoff plate
•4. Already has a built in
derotational screw

13. Proximal Femoral NailProximal Femoral Nail
DHS + TSP + Med Off = PFN
Derotational
Screw

14. Which Appears More Stable ?Which Appears More Stable ?
Cantilever 3
rd
order
Requires medial intactness to work
Will fail if posteromedial comminution+
1
st
Order lever

15. THANK YOUTHANK YOU
[email protected]@gmail.com
Dr. B. Shivashankar.Dr. B. Shivashankar.
SolapurSolapur


ISO 9001:2008
Certified
Hospital