pfn biomechanics

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Cephalomedullary Nailings Cephalomedullary Nailings (PFN / TFN) (PFN / TFN) In Unstable Inter Trochanteric Fractures In Unstable Inter Trochanteric Fractures And its Biomechanical Considerations And its Biomechanical Considerations Dr. B. Shivashankar. Dr. B. Shivashankar. Solapur Solapur ISO 9001:2008 Certified Hospital

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How PFN scores over DHS for inter trochanteric fractures.

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Page 1: Pfn biomechanics

Cephalomedullary Nailings Cephalomedullary Nailings (PFN / TFN)(PFN / TFN)

In Unstable Inter Trochanteric Fractures In Unstable Inter Trochanteric FracturesAnd its Biomechanical ConsiderationsAnd its Biomechanical Considerations

Dr. B. Shivashankar.Dr. B. Shivashankar. SolapurSolapur

ISO 9001:2008Certified Hospital

Page 2: Pfn biomechanics

Stable Easy to treat by any method

Un StableDIffficult 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

Page 3: Pfn biomechanics

Gradual # CollapseGradual # Collapse

Barrel allows the screw to slide gradually during the course of fracture healing

Page 4: Pfn biomechanics

Intact Lateral wall – Key for determining outcome

Page 5: Pfn biomechanics

Pre Operative Day 1

31. A2.1 31. A3. 3

31% of A2 Type Fractures

Page 6: Pfn biomechanics

Day 40 Day 70

Page 7: Pfn biomechanics

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

Page 8: Pfn biomechanics

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

Page 9: Pfn biomechanics

DHS Improvements 1985-1999

To Prevent To Prevent Medialisation – T S PMedialisation – T S P

Page 10: Pfn biomechanics

Slide Courtesy: Indiaorth

Page 11: Pfn biomechanics

Dynamisation along Dynamisation along ShaftShaft

Medoff plate also requires an intact lateral wallOtherwise too much medialisation happens as show here

Page 12: Pfn biomechanics

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

Page 13: Pfn biomechanics

Proximal Femoral Proximal Femoral NailNailDHS + TSP + Med Off = PFN

Derotational Screw

Page 14: Pfn biomechanics

Which Appears More Which Appears More Stable ?Stable ?

Cantilever 3rd orderRequires medial intactness to workWill fail if posteromedial comminution+

1st Order lever

Page 15: Pfn biomechanics

THANK YOUTHANK YOU

[email protected]@gmail.com

Dr. B. Shivashankar.Dr. B. Shivashankar. SolapurSolapur

ISO 9001:2008Certified Hospital