Proximal Femoral Nail

Bone fractures are a very common orthopedic injury resulting from trauma and sudden loads or stresses applied to bones or a result from bones being weakened by certain diseases. More than 250,000 femur fracture patients are seen per year in the U.S. on average. Bone fractures are either a complete or partial break in a bone and in some cases a simple cast to immobilize the injury site is not enough to completely heal the fracture.
Immobilization from casts may not be enough to completely heal the fracture if a malunion (when both ends of the fractured bone misalign) occurs and/or if a non-union (when the fracture gap is too large and the fractured ends cannot re-attach to one another) occurs. In the case of a malunion or non-union, a possible solution to the problem is by surgically inserting an intramedullary rod into the center canal (diaphysial) region of the injured bone and fixating it into place with screws. �

1. Proximal Femoral Nail BY ALEX BERTINO, COREY VAN DE HAY, ANDREW HNAT ACA ENGINEERING ‹#›

2. Background Designed for femur injuries Largest and strongest bone Causes of injury Automobile accidents Falling Description of Fracture Location Pattern Skin condition Treatment based on type of fracture ‹#›

3. Medical Need More than 250,000 patients per year Cast insufficient in certain cases Malunion Non-union Necessitates usage of intramedullary rod Malunion Non-union ‹#›

4. Predicate Device Device Approval Date January 1997 Product Code: JDS No recalls for this device in particular 10 recalls since 1995 for all JDS devices Standard Length PFN Synthes offers two options for PFN length ‹#›

5. The Device Components Nail Screws (2 Self-Tapping, 1 Locking) Threaded End Cap Material Titanium Alloy, Ti-6Al- 4V(Nb) Intended use Indefinite Fixation within Intramedullary C anal Stabilization and Bone Integration ‹#›

6. Design and Assumptions Anatomical geometry Biocompatible material Load transfer Restrict Stress Shielding ‹#›

7. Finite Element Analysis Force: 6267 N Tripping Average male over 20 years Applied to the top of the rod Fixed at each screw hole Multiple Simulations Normal Bending Torsion Buckling/Frequency ‹#›

8. FEA Analysis: Normal Force Order of magnitude lower than yield stress Stress singularity at hole Caused by boundary condition Not physically accurate Stress too low to cause fatigue damage ‹#›

9. FEA Analysis: Bending Tighter stress distribution Excessive stress at hole Singularity Not physically accurate Peak Stress half of yield stress System will not fail under these conditions ‹#›

10. FEA Analysis: Torsion Tightest stress distribution Excessive stress at hole Singularity Not physically accurate Peak Stress slightly lower than bending System will not fail under these conditions ‹#›

11. FEA Analysis: Buckling/Frequency Critical load factor: 183.7 Minimum resonance frequency: 2071.6 Hz System will not fail due to Buckling/Frequency Buckling Frequency ‹#›

12. Manufacturing and Sterilization Wet (steam) autoclave sterilization Implanted medium to long-term device Sterilization level: 10 -6 SAL Titanium casting to account for semi-complex geometry Initial barrier costs high, but long-term production will prove economical Casting Steam Autoclave ‹#›

13. Verification and Validation 510(k) Submission Substantial equivalence approach Predicate device Synthes PFN (Femur Intramedullary Rod and Screws) - Std. Length Device Testing Static 4-point bending Static Buckling Static torsional Fatigue bending Static Bending, Buckling, & Torsion Testing ‹#›

14. Conclusion Fills a medical need Large market for femur implants Cost-effective to mass produce FEA analysis yielded positive results Further testing needed Positive outlook based on current results ‹#›

15. References https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K970097 https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPCD/classification.cfm?ID=JDW https://www.accessdata.fda.gov/cdrh_docs/pdf/K970097.pdf https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfTPLC/tplc.cfm?ID=4455&min_report_year=1995 https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfTPLC/tplc.cfm?ID=4453&min_report_year=1995 http://synthes.vo.llnwd.net/o16/LLNWMB8/INT%20Mobile/Synthes%20International/Product%20Support%20Material/legacy_Synthes_PDF/DSEM-TRM-0714-0122-1_LR.pdf https://en.wikipedia.org/wiki/Femur ‹#›

16. References http://52.62.202.235/sites/default/files/TDwyer/Tibial%20Hypertrophic%20Nonunion%20.jpg http://www.afrjpaedsurg.org/articles/2011/8/1/images/AfrJPaediatrSurg_2011_8_1_34_78666_f2.jpg ‹#›