1. Orthopedic Adaptor Oral Presentation #4 Kate Huddleston Anna Duloy Alexander Byall Ashley Goodnight

2. Schematic of Femur and Tibia

3. Schematic of Knee with Prosthesis (pre-periprosthetic Fracture) 300,000 total knee replacements per year

4. Schematic of Femur and Tibia post- Periprosthetic Fracture 7,500 Periprosthetic Fractures Per Year

5. Project Definition To design an adaptor that will connect the nail inserted into the shaft of the femur to the knee prosthesis, in the event that a periprosthetic femoral fracture has occurred

6. List of Constraints Hold the nail 5 degrees relative to the prosthetic joint Universal Maintain rigid structure Irremovable knee prosthesis Compatible with both right and left knee

7. Project Background Periprosthetic femoral fractures These fractures occur: –when femur weakens during surgery –in patients with osteoporosis and rheumatoid arthritis Patent Search - no current method to attach nail and prosthesis

8. Importance 300,000 total knee replacements per year. Of these there are 7,500 cases of periprosthetic femoral fractures (Incidence rate 0.6%-2.5%) Target population: average age of patient is about 68, but age ranges from 42-92 years

9. Cost Cost of periprosthetic femoral fracture repair: –$30,000 (physician, hospital stay, radiology) Cost of adaptor: –Exact price unknown at this point –Material decided as titanium, but specifications undecided

10. Attachment Mechanism Brainstorm on pros and cons of each Practicality of design Ease of use Twist and lock was a possible mechanism:

11. Initial Adaptor Schematic

12. 2 nd Adaptor Schematic

13. Current Adaptor Schematic

14. Adaptor Advantages Significantly quicker procedure –2 pins versus 4 Less surgical dissection –Less blood loss Better way to maintain alignment between femur and prosthetic knee

15. Factors to consider: –Compatibility with nail (same material) and prosthetic material –Oxidation reactions, Galvanic corrosion –Strength –Expense –Availability –Chosen Material: titanium (Grade 5 or 6-4) - nail and adaptor cobalt chrome - knee Biomaterials

16. CAD Drawing for Current Schematic

17. CAD Drawing with Applied Stresses Analysis for 100 N applied to both sides The maximum stress is 1500 MPa. Yield stress for titanium 6-4 is 800 MPa, so our adaptor would break.

18. Difficulties Head of the screw – too big Waiting for exact dimensions of the retrograde femoral nail Difficultly measuring the prosthesis

19. Prototype Machine Shop: Cupples J&J Co., Inc. in Jackson, TN Contact: John Landrum Plastic prototype not possible Titanium prototype wired with EDM Not to cost over $200

20. Current Status Weekly meetings in Med Center Orthopedics Lab with Advisors Attachment Mechanism –Details (dimensions) –Schematic –Specifications –CAD Drawing, Solidworks Contacted Johnson & Johnson Waiting retrograde femoral nail

21. Future Work Determine stresses on prototype Continue work on CAD Research mechanical properties of titanium 6-4 Work on installation procedures Continue meeting with advisors Set up meeting with Dr. King for needs

22. Acknowledgements We would like to thank the following people for their help: –Dr. Limbird –Jeff Gordon –Sue Larson –Mike Bailey –Dr. King

23. References http://www.emedicine.com/orthoped/to pic254.htmhttp://www.emedicine.com/orthoped/to pic254.htm http://www.orthoteers.co.uk/Nrujp~ij33 lm/Orthtkrperiprosthfrac.htmhttp://www.orthoteers.co.uk/Nrujp~ij33 lm/Orthtkrperiprosthfrac.htm http://www.eng.hull.ac.uk/research/me dical/fracture_plate_intro.htmhttp://www.eng.hull.ac.uk/research/me dical/fracture_plate_intro.htm