Plating principle for orthopaedic fixation

1.  Dr. Abdul Razak Bin Haidzir
Orthopaedic Department,
HOSPITAL PUTRAJAYA.

2. WHAT AM I
COVERING
• Role of Implant
• Advantages of Implant
• Principle of fixation
• Design of principle
• Dynamic Compression
Plate
• Biomechanics of DCP
• Bridge Plating

3. WHY FIX
FRACTURES?
• To maintain alignment until healing
(union) takes place
• To provide mobility
while healing occurs
• To reduce morbidity

4. ANATOMIC
ALIGNMENT
• Joints
• Radius & Ulna

5. AXIAL
ALIGNMENT
• Long Bone #
• Children

6. INTERNAL
FIXATION - WHY??
• Early stability
• Early Range of Motion
• Reduction of pain and
discomfort
• Reduced malunion
• Increased infection risk
• Periosteal stripping
• Fixation Failure

7. ROLE OF
IMPLANT
• Add stability
• Fracture fixation
• A plate used after osteotomy
• Replace damaged or diseased
part
• Total joint replacement
Healing Stimulation

8. ADVANTAGES OF
IMPLANTS
• No casts
• Prevent skin pressure and fracture
blisters
• No scars
• No complications of bed rest
• – Important for the elderly
• Early motion
• –Avoid stiffness
• –Enhance fracture healing
• –Prevent muscle atrophy

9. PRINCIPLE OF
FIXATION
• Rigid Fixation
• Stress distribution
• Fracture stability
• Compression
• Stability
• Fracture Healing
• Primary bone
healing

10. DESIGN
PRINCIPLES
• Plate + Bone = Absolute Rigidity
• No damage to periosteal blood
supply
• Position of plate – tension side
• Soft tissues intact
• Correct Materials & Design

11. DYNAMIC
COMPRESSION
• Special oblong screw holes with differential slopes to
allow for
FRACTURE COMPRESSION

12. DYNAMIC
COMPRESSION

15. BIOMECHANICS OF
DYNAMIC
COMPRESSION
PLATE(DCP)
• Designed to
compress the
fracture
• Offset screws exert
force on specially
designed holes in
plate
• Force between screw
and plate moves
bone until screw sits
properly
• Compressive forces
are transmitted
across the fracture

16. • Alternative Method
• External
Compression
Screw control

19. HOW MANY
SCREWS
• Generally, 6 cortices each side of the fracture
• Depends on the bone & space available
• Weight bearing bones and comminuted fractures need
more screws

21. BRIDGE
PLATING
• Newer idea / Older Idea
• Preserves the healing tissues - periosteum , blood
supply
• Minimal disruption of soft tissue envelope over the
fracture site
• IMPROVED Healing in DIFFICULT fractures

22. BRIDGE
PLATING
• Go to One End
• Incise and Enter
Plate
Subcutaneously
• Fix Only distal and
Proximal

23. BRIDGE
PLATING
• Fixation is not as rigid as before
• RELATIVE STABILITY
• Not be stable enough to weight bear
• May require additional external
fixation
• Suitable for Mid-diaphyseal fractures
• SECONDARY BONE HEALING

25. Definition:
Absolute stability = Rigid Fixation
• Little or reduced displacement
• Allows direct healing without callus
• Reduces vascular damage or
instability
• Promotes healing
• Pain control
• Allows early movement

26. Histological sequence:
• Days - Haematoma  resorbed and / or
transformed to repair tissues, swelling  ,
wound heals
• Weeks - Haversian remodelling; gaps fill
with lamellar bone transverse to the bone
long axis

27. Histological sequence:
• Subsequent weeks
• Cutter cones of osteons cross fx in
areas of contact or minute gaps
• Consequent interdigitations of osteons

28. Biomechanics and biology of stable fx fixation
•Precise diaphyseal fracture fixation is no
longer necessary
• Blood supply more important
• Intra-articular precise reduction is still mandatory
• Absolute stability beneficial for blood vessels to
grow across fx

29. Foot print of platedisturb periosteal blood supply
 bone necrosis of cortex under plate
 temporary porosis +/- sequestration
• Recent studies  reduction of implant and bone
interface improves healing and reduce local
infection
• Special implants:
LC-DCP, internal fixators (PC-Fix),Locked
screws

30. LC-DCP
PC-Fix

32. Four-Screw Plate Fixation vs Conventional Fixation for
Diaphyseal Fractures of the Forearm
Seyed Abdolhossein Mehdi Nasab, Nasser Sarrafan, and Saeed Sabahi
Abstract Backgrond:
Standard treatment of diaphyseal fractures of the forearm is open reduction and fixation using dynamic compression plates (DCP) and screws. This technique uses screw placement in
all 6 or more of the plate holes except the hole over the fracture line. We hypothesized that DCP with selective 4-screw bicortical placement can provide adequate fixation for these
fractures.
Keywords: Forearm, Fracture, Fixation
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4004990/

33.  Objectives:
 The aim of this study was to evaluate the results of conventional 6 or more screw fixation versus 4 screw fixation for adults with diaphyseal fractures
of the forearm.
 Patients and Methods:
 In this prospective study, 128 fractures of the ulna, radius or both bones of the forearm in 87 patients were treated in either one of these two groups: Open
reduction and internal fixation (ORIF) with conventional DCP and screws or ORIF using DCP and selective 4- screw placement. Fractures were transverse
or oblique in pattern without gross comminution. In a total of 41 patients with fractures, 28 single ulnar and 18 single radius fractures were included. Follow-
up visits were done at 3-6 and 12- 16 weeks and at 6 months. Outcome with respect to union an nonunion rates, union time, infection, and device failure was
noted.
 Results:
 No change in alignment was noted in any patient. Union time in conventional and selective bicortical 4-screw fixation was
 74.8 days and 73.6 days respectively which showed no significant difference (P = 0.064). Union rate and infection was 92.1% and 3.2% in conventional
and 95.3% and 0% in the selective group respectively. Non-union was observed in 5 and 3 cases of fractures in conventional and the selective group
respectively.
 Conclusions:
 For treatment of the transverse or oblique diaphyseal fractures of the forearm, fixation by a same length 3.5 mm DCP with selective 4-screw cortical
fixation (2 screws on each side of the fracture site) had similar results in comparison with conventional 6 or more DCP screws. Because of lesser impact
on host bone and smaller incision, the selective 4-screw insertion can be an alternative technique for treatment of these fractures.

34.  Minimal damage to cortex, decrease the
time of the surgical procedure and lower
refracture risk after plate removal.
 internal fixation of diaphyseal fractures
of the radius, ulna or both bones of the
forearm with a standard length DCP and
selective 4 cortices or 6 screw fixation
had similar results.
 Thus, as less damage to host bone is
caused we recommend DCP with 4
cortices screw fixation when the fracture
pattern is simple transverse or oblique
without gross contamination

35.  The main disadvantage of this method
may be a less rigid fixation