screw ppt

1. PRESENTED BY:
GUIDED BY: DR DEEPESH KHURANA
DR ADITYA TRIPATHI PG RESIDENT CMCH
BHOPAL ASSISTANT
PROFESSOR
SCREWS(IN
ORTHOPAEDICS)

2. WHAT IS A
FRACTURE?

3. TEXT
PRINCIPLES OF FRACTURE FIXATION:
▸ FRACTURE REDUCTION TO RESTORE ANATOMICAL RELATIONSHIP
▸ FRACTURE FIXATION PROVIDING ABSOLUTE OR RELATIVE STABILITY
▸ PRESERVATION OF BLOOD SUPPLY
▸ EARLY AND SAFE MOBILIZATION

4. DEFINITION: A SCREW IS A DEVICE WHICH CONVERTS ROTATIONAL FORCES INTO
LINEAR MOTION
ANATOMY OF A SCREW
▸ HEAD
▸ SHAFT
▸ THREAD
▸ TIP

5. TEXT
THE SCREW HEAD:
▸ SERVES AS AN ATTACHMENT TO
SCREWDRIVER
▸ FIVE COMMONLY USED TYPES OF RECESS:
▸ WHAT IS COUNTERSINK?
▸ FUNCTION OF SCREW HEAD

6. TEXT
SHAFT OF SCREW:
▸ SMOOTH LINK BETWEEN HEAD AND THE THREAD
▸ RUN OUT

7. TEXT
THREAD OF A SCREW
▸ CORE DIAMETER
▸ PITCH
▸ LEAD
▸ OUTSIDE DIAMETER
▸ DIFFERENT THREAD DESIGN

9. TEXT
TIP OF A SCREW
▸ TYPES OF TIP:
▸ SELF TAPPING TIP
▸ NON -SELF TAPPING TIP
▸ CORKSCREW TIP
▸ TROCAR TIP
▸ SELF-DRILLING SELF TAPPING TIP

10. TYPES OF SCREWS IN
ORTHOPAEDICS

11. ▸ WOOD SCREWS :
FORM THEIR OWN MATING THREADS.
FORCE ARISES FROM THE DEFORMATION
OF SURROUNDING MATERIAL.
▸ MACHINE SCREWS:
MATING THREADS TO BE CUT BY ‘TAP’.
FORCE COMES FROM THE SHANK OF THE
SCREW.

12. CORTICAL BONE SCREW
▸ MACHINE TYPE SCREW
▸ THREADS SMALLER IN DIAMETER
▸ LOWER PITCH
▸ THREADS TO BE CUT IN PILOT HOLE PRIOR
TO ITS INSERTION
▸ FORCE COMES FROM ELASTIC
DEFORMATION OF BONE

13. CANCELLOUS BONE
SCREW
▸ MODIFIED WOOD TYPE SCREW
▸ TIP NOT TAPERED,LARGER THREADS
▸ HIGHER PITCH
▸ CORE DIAMETER < SHAFT DIAMETER
▸ INSERTED INTO UNTAPPED PILOT HOLE
▸ SPRING REACTION COMES FROM
CANCELLOUS BONE

14. ON THE BASIS OF NEED OF TAPPING:
SELF TAPPING SCREWS
▸ INSERTED DIRECTLY INTO A PRE DRILLED
HOLE
▸ THREAD FORMING TYPE
▸ THREAD CUTTING TYPE
▸ REINSERTION
▸ ADVANTAGES

15. NON-SELF-TAPPING
SCREW
▸ INCAPABLE OF CUTTING A BONE THREAD
▸ USED IN HARD CORTICAL BONE

16. ON THE BASIS OF THREADS
▸ FULLY THREADED SCREW:
CORTICAL BONE SCREW IS USUALLY FULL
THREADED
CANCELLOUS SCREW :TO FIX BONE PLATE
▸ PARTIALLY THREADED SCREWS:
AKA SHAFT SCREW
BETTER STRENGTH AND STIFFNESS
CANCELLOUS SCREW : USED AS LAG
SCREW

17. CANNULATED SCREW
▸ USED OVER A GUIDE WIRE
▸ CANCELLOUS CANNULATED SCREW:
LARGE/SMALL
▸ LARGER ROOT DIAMETER
▸ INTERNAL HEXONAL RECESS / EXTERNAL
HEXONAL HEAD
▸ CLOCKWISE/COUNTERCLOCKWISE
ROTATION

18. LOCKING SCREW:
▸ THREADS ON
UNDERSURFACE/COUNTERSINK OF THE
HEAD
▸ HEAD IS CONICAL WITH
HEXAGONAL/HEXALOBULAR RECESS
▸ COMPACTED PITCH AND BENEFIT OF 2
THREAD ON HEAD
▸ USED IN LOCKED INTERNAL FIXATOR PLATE
HOLE

19. SPECIAL TYPES OF
SCREW

20. HERBERT SCREW
▸ NO HEAD,THREADS ON BOTH END
▸ DIFFERENTIAL PITCH —>
INTERFRAGMENTARY COMPRESSION

21. INTERFERENCE SCREW
▸ DIRECT TENDON TO BONE FIXATION
DEVICE
▸ SCREW THREADS ENGAGE AND COMPRESS
TENDON FOR FIXATION
▸ MOST COMMONLY USED IN ACL
RECONSTRUCTION

22. MALLEOLAR SCREW
▸ USED FOR FRACTURE FIXATION OF SMALL
FRAGMENTS IN CANCELLOUS BONE

23. LOCKING BOLTS
▸ USED TO SECURE INTRA MEDULLARY NAILS

24. DYNAMIC HIP SCREW
▸ CONTROLLED DYNAMIC SCREW AKA
RICHARD’S SCREW
▸ DYNAMIC ACTION PREVENTS SCREW CUT
OUT AND PENETRATION INTO HIP JOINT

25. BIOABSORBABLE
SCREWS
▸ POLYGLYCOLIDE : ABSORB EASILY,EARLY
LOOSENING
▸ CRYSTALLINE POLYACTIDE: YEARS TO
ABSORB
▸ COMPOSITE OF PLA AND TRICALCIUM
PHOSPHATE

26. LAG SCREW
▸ IT IS A TECHNIQUE OF INSERTION
▸ COMPRESSION BETWEEN TWO BONE
FRAGMENTS
▸ GLIDE FREELY THROUGH NEAR FRAGMENT
AND ENGAGE ONLY FAR FRAGMENT

27. MEASUREMENT OF
SCREW LENGTH
▸ DEPTH GAUGE IS USED
▸ IN CORTICAL BONE: MEASURED AFTER
COUNTERSINKING BUT BEFORE TAPPING
THE THREAD.
ONE THREAD SHOULD EXIT THE FAR
CORTEX

29. THANK YOU
!!!!!
DR DEEPESH
KHURANA