Basic implant ortho

VERY BASIC IMPLANT

1. ORTHO BASIC IMPLANT (SCREWS &PLATES) PRESENTED BY: SN ABA BERIAK SN LORNA SIDIN

2. SCREWS

3. Screws introduction An elementary machine to change the small applied rotational force into a large compression force Function -holds the plate or other prosthesis to the bone -fixes the fracture fragments (position screw) - Achieves compression between the fracture fragments (Lag screw)

4. Screws Head means for applying torque with a screwdriver act as a stop (the undersurface) i.e. countersunk 2. Recess type slotted Cruciate Philips Hex/Allen Torx ( eg Stardrive of synthes )

5. Screws 3. Shaft/Shank Smooth link almost not present in standard cortex screw Present in cortical shaft screw or cancellous screw Run out – transition between shaft and thread, - site of most stress riser, screw break when - incorrectly centered hole - hole not prependicular to the plate 4 . Thread Invlined plane encircling the root Single thread May have two or more sets of thread V-thread profile: more stress at sharp corner Buttress thread profile: less stress at the rounded corner

6. Screws 5. Core Diameter Narrowest diameter across the base of threads Also the weakest part Smaller root –shear off Torsional strength varies with the cube of its root diameter

7. Screws Thread Cortical screws

8. Cancellous screws Screws Thread

9. Locking screws Screws Thread

10. Screws

11. Screws

12. Screws

13. NAME MECHANISM Plate screw Potential and friction applied to create force between the plate and the bone Lag screw The glide hole allows compression between bone fragments Position screw Holds anatomical parts in correct relation to each other without compression, ie , thread hole only, no glide hole Locking Head screw Used exclusively with LCP/LISS; thread in the screw head allow mechanical coupling into a reciprocal thread in the plate and provide angular stability Interlocking screw Couples an intramedullary nail to the bone to maintain length, alignment and rotation Anchor screw a point of fixation used to anchor a wire loop or strong suture Push-pull screw A temporary point of fixation used to reduce a fracture by distraction and/or compression Reduction screw Conventional screw used through a plate to pull fracture fragments towards the plate; the screw may be removed or exchanged once alignment is obtained. Poller screw Screw used as a fulcrum to redirect an intramedullary nail Screws Function

14. PLATES

15. Plate Definition by Oxford Dictionary A thin, flat sheet or strip metal or other material, typically one used to join or strengthen things or forming part of a machine.

16. First record of plates for the long bones 1886 by Hansmann , of Heidelberg University, Germany Historical introduction

17. Historical introduction

18. Since 1958, AO has devised a family of plates for long bone fractures, starting with a round holed plate. In 1969 the DCP was developed. In 1994 LC DCP was created. In 2011 LCP with combination holes has come into use Historical introduction

19. Plates… P lates are now widely accepted with different standard techniques of osteosynthesis , throughout the skeleton. Different anatomical locations demand different shapes and sizes of plates.

20. Dynamic compression plates (DCP) Limited contact dynamic compression plates (LCDCP) Locking compression plates (LCP) Reconstruction plates Tubular plates Anatomic plate Plates Design

21. Plates Functions

22. 1969 – DCP was developed Has a self-compressing hole design Experimental work showed that the flat undersurface of the DCP interfered with blood supply of the underlying cortex onto which it was compressed by the screws. The concept of the ‘footprint” of plate emerged. The “footprint” is the area of the undersurface of the plate in contact with the underlying bony cortex. Dynamic Compression Plates (DCP)

23. DCP

24. Unstable fixation leads to fatigue and failure Strict adherence to principles of compression Compromised blood supply due to intimate contact with underlying cortex “ refractures ” after plate removal Problem with DCP

25. Represents a design change Overcome problems with DCP Plate footprint reduced- improved blood circulation Limited Contact Dynamic Compression plates (LC-DCP )

26. Minimized kinking at screw holes, more countourable and reduced plate fatigue at hole Allow more inclination of screw in longitudinal plane and transverse plane Limited Contact Dynamic Compression plates (LC-DCP )

27. Since 2001 the LCP with combination holes has come into use. LCP has a combi hole which permits the insertion of standard head screws and threaded locking head screws. Angular-stability whereas stability of conventional plates is friction between the plate and bone. Also designed with a minimal footprint. Locking Compression Plates (LCP)

28. Have notched between the holes to permit bending ‘on the flat’ as well as conventional bending. Very adaptable, using the correct tools and are useful in complex anatomical sites such as the distal humerus , the pelvis, the clavicle, acetabulum, etc. Reconstruction Plates

29. 1mm thick Useful in areas with minimal soft-tissue covering such as lateral malleolus, olecranon, distal end of the ulna. Tubular Plates

30. Fixed to the two main fragments only, leaving the fracture zone untouched. Respect the biology of a complex and to minimize any additional soft-tissue injury Bridge Plates

31. Extramedullary splint Provide relative stability Maintain length, rotation, axis Healing with calus formation Bridge Plates

32. REFERENCES: References: 1. www.orthobullets.com /basic-science/9063/ orthopaedic 2. Aotrauma.aofoundation.org /plate-form and function 3. www.slideshare.net/screws and plates fixation/ BaHuong