Orthopedic implants.pptx

presenting the design of the knee, hip, and ankle implants.

1. Orthopedic implants Prepared by T/A CPO TUMAINI MATANDALA

2. Orthopedic implants

3. Orthopedic implants CONTENTS OF THE TOPIC …… Define the implants in the Orthopedic field. Historical back grounds of the designs of the Orthopedic Implants. Needs of the Orthopedic implants. Types/Designs of the Orthopedic Implants .

4. Definition of the orthopedic implants Orthopedic implants are medical devices involving the musculoskeletal system . Generally used to……….. Restore function to synovial joints , bone , and the spine .

5. Need of the orthopedic implants Increasing geriatric population across the globe has results into surging demand of the orthopedic implants, as old aged people suffer more from Osteoarthritis Rheumatoid arthritis Osteoporosis And other musculoskeletal disorders due their vulnerable bones. Other factors which increase the demands of the orthopedic implants are: Increasing umber of road traffic accidents Low bone density problems Increasing number of the trauma --- Fracture cases.

6. Historical back ground of the ortho-implants Materials have changed significantly in the historic evolution of total hip replacements and other orthopedic devices from the initial use of ivory , glass , and grouting agents to………contemporary alloys and polymers that provide resistance to corrosion, fatigue, and wear. In the past, implants were designed with insufficient cognizance of biomechanics. Accordingly, the clinical results were not very encouraging. An upsurge of research activities into the mechanics of joints and biomaterials has resulted in better designs with better in vivo performance .

7. Historical back ground of the ortho-implants Most of the orthopedic implants were lack either of the following general requirement of biomaterials, that are: Biocompatibility. Sufficient strength within dimensional constrains. Corrosion resistance.

8. Historical back ground of the ortho-implants As a result, researchers and surgeons have developed and used fixation devices for the joints. A large number of devices are also available for the repair of the bone tissue ,contemporary scientific work related to the use of biomaterials for the repair of bone (fracture) and joint replacements ranging from a hip joint to a spine. From this perspective, stainless steel , cobalt–chrome alloys , and titanium alloys are most suitable

9. TOTAL HIP REPLACEMENT

10. INTERNAL FIXATION

11. Types and design of the ortho Internal Fixation Devices . For the immobilization of the bone fractures. Can either be temporally or permanent in vivo. Contemporary total joints replacement. For the replacement of the traumatized / degradated joints. Its always permanent in vivo.

12. INTERNAL FIXATION AND TOTAL HIP REPLACEMENT

13. PROSTHETIC KNEE REPLACEMENT

14. InteRnal fixation Internal Fixation Devices . Wires and cables Pins Screws Plates intramedullary nails

15. Plates Plates are available in a wide variety of shapes and are intended to facilitate fixation of bone fragments. The rigidity and strength of a plate in bending depends on : The cross-sectional shape (mostly thickness). Material from which it is made.

16. Biomaterials Applications in Internal Fixation Materials Properties Application Stainless steel Low cost, easy fabrication Surgical wire (annealed) Pin, plate, screw IM nail Ti alloy (Titanium) High cost , Low density and modulus, Excellent bony contact Surgical wire , Plate, screws, IM nails Co–Cr alloys ( Cobalt –Chromium alloys) High cost, High density and modulus, Difficult fabrication Surgical wire, IM nails PLA - polylactic acid /polyglycolic- PGA Resorbable Weak strength Pin, screw Nylon Non resorbable plastic Cerclage band

17. Wires and cables Surgical wires and cables are used to reattach large fragments of bone, like the greater trochanter, which is often detached during total hip replacement. When a wire is used with other metallic implants, the metal alloys should be matched to prevent galvanic corrosion (Park and Lakes 2007).

18. Pins Primarily, Pins are used to hold fragments of bones together provisionally or permanently and to guide large screws during insertion. Straight wires are called Steinmann pins Kirschner wire. If ( pin diameter is <2.38 mm) Most pins are made of stainless steel . however, recently, biodegradable pins made of PLA or PGA have been employed for the treatment of minimally loaded fractures .

19. Bone Screws Screws are the most widely used devices for fixation of bone fragments. There are two types of bone screws: (1) cortical bone screws ( which have small threads) (2) cancellous screws (which have large threads to get more thread-to-bone contact.)

20. Bone Screws a non-self-tapping cancellous screw (pedicle screw) a self-tapping V-threaded screw (has a cutting flute

21. Plates

22. intermedullary Nails Intramedullary devices (IM nails) are used as internal struts, to stabilize long bone fractures. A gamut of designs are available, going from solid to cylindrical, with shapes such as cloverleaf, diamond, and “C.

23. Intermedullary Nails