A total hip replacement (THR) system is designed to restore hip functionality and improve long-term performance by reducing pain. A THR involves surgically replacing damaged hip joints with prosthetic components, including a femoral stem, femoral head, and acetabulum cup. The design of this THR system was created using inputs like commercially available prosthetic femurs and considers features like a collar for ease of removal and weight transfer between components.

1. By Ujwal A. Parikh Total Hip System

2. Scope A Total Hip Replacement (THR) system is designed to restore the functionality and improve the long term performance of the hip implant, thus reduce pain.

3. What is THR? A total hip replacement (THR) - also called a hip arthroplasty - is a surgical procedure that re-forms the hip joint. THR system used today has three components – the femoral stem , the femoral head , and the acetabulum . Each component has multiple sizes which allow for a custom fit. It is done for disorders like osteoarthritis , rheumatoid arthritis , traumatic arthritis , Avascular necrosis and other reasons as malignant bone and paget’s disease.

4. Why THR? Normal Hip Smooth weight bearing surfaces Smooth cartilage Arthritic Hip Rough bone Bone spurs Irregular weight-bearing surfaces Worn cartiliage Narrow joint space An Xray report of the pateint for diagnosis.

5. Design Input (References) Basic Sketch of Femur Neck Commercially available Prosthetic Femur from Endotec

6. Basic Sketch of Femoral Stem

7. Femoral Neck Geometry

8. Femoral Stem Upper part fits into femoral head Lower Part goes into Femoral Shaft Fixed Stem Modular Stems available Axis in alignment with peak load vector

9. Filleting Details

10. Features Of Design Collar (Ease of removal and weight transfer) 14/12 Taper Fit (Best fit) Rounding of inner surfaces (Maximum load distribution)

11. Head

12. Basic Sketch of Head Tapered Inner Diameter for best fit Modular heads available Axis in alignment with axis of femur neck and peak load vector

13. Design Feature Substantial outer spherical surface provides maximum range of motion for the Acetabular cup . It provides maximum resistance against cup seperation Made from high molecular polymer to provide smooth rotation.

14. Femoral Stem and Head

15. Acetabular Cup

16. Basic Sketch of Cup Modular Cups Outer and inner diameter can be customized

17. Design Feature Grooves: reduces wear basically reducing friction and extending the useful life of artificial joints Cement locking mechanism with the hip socket can be increased.

18. Complete Assembly

19. Exploded View

20. Design Output The design of THR system was created using the design inputs given This is one of the many commercially available hip implants, however best suited hip implant is highly dependant on the patient The design can be completely customized depending on the patients need.

21. References http://endotec.com/pdf/Hip%20Brochure.pdf http://www.patentstorm.us/patents/5972033/claims.html http://www.wikipedia.org/ www.joint-replacements.com

22. Thank You