Plates-form and function

Pre Basic Course

Plates - form and function

Dr Sudarshan Bhandary

Plate : Form and Function

• To understand how changes in the design of plates has evolved to meet the needs of the patient

• To understand how you can use a plate in several different ways to achieve different types of fixation

Plate : Form and Function

• Absolute stability challenged by biological fixation

• Osteosynthesis with plates has a firm place in # treatment

• Articular #s require stable fixation• Compromise of cortical blood supply a major

drawback of conventional plating

Plate : Form

• DCP• Reconstruction plate• Semitubular - 1/3rd Tubular Plate• LC-DCP• PC-FIX• LCP• LISS

DCP - 3.5 and 4.5

• First introduced in 1969 by Danis

• Revolutionary concept of compression plating

• Featured a new hole designed for axial compression

• Broad 4.5 for Femur & Narrow 4.5 for Humerus &

Tibia

• DCP 3.5 for Forearm, Fibula, Pelvis & Clavicle

• The screw hole in DCP is like a portion of an inclined & angled cylinder

• When the screw is tightened it results in a movement of bone fragment in relation to the plate

• Screw holes allow 1mm compression

• Additional compression with 1 more eccentric screw before locking first screw

• Oval shape allows 25* inclination in longitudinal & 7* in transverse plane

Technique of application3 drill guides

a) Concentric (Neutral) - Green collar - 0.1 mm offset

b) Eccentric (Load) - Gold collar - 1 mm offset

c) Universal for buttress mode

Problems with DCP

• Unstable fixation leads to fatigue & failure

• Strict adherence to principles of compression

• Compromised blood supply due to intimate

contact with underlying cortex

• “Refractures” after plate removal

LC-DCP

• Represents a design change • Overcome problems with DCP• Plate footprint reduced• Minimized kinking at screw holes• Allows more inclination of screw in

longitudinal plane

Technique of application

• New spring loaded drill guide• Without pressure - Eccentric hole• With pressure - Neutral

Tubular plates

• 3.5 system - 1/3rd Tubular• 4.5 system - Semitubular • Limited stability• Collared hole

• Lateral malleolus• Distal ulna / Olecranon• Distal humerus

Reconstruction plates

• Deep notches between holes• Accurate contouring in any

plane

• Pelvis • Acetabulum• Distal humerus• Clavicle• Olecranon

New Systems• Abolish ill effects of plate to bone contact• Concept of “Internal Fixator”• PC - FIX = First implant designed• Self tapping, unicortical, one length screws• Locking head

LCP – Locking Compression Plate

L C P

• Latest in the evolution• “ Internal fixator ”• Combination of locking

screw with conventional screw

• Extraperiosteal

location of plate

LCP

• Fixed angle stability• Unicortical fixation

option• Load & neutral position

of screws• Conical screw head• Large diameter

LISS-Less Invasive Stabilization System

LISS

Plate: Function

Principles of rigid internal fixation with plates

• Neutralization Plate• Compression plate• Buttress Plate• Bridge Plate • Tension Band Plate

Neutralisation Plate

• Used with lag screws , plate is protective

• Neutralises the weight bearing forces to protect the lag screws from axial loading

• Lag screw generates forces of 3000 N

Compression plating

Techniques

• With dynamic compression principle (DCP/LC-DCP)

• With tension devise• By contouring plate• Additional lag screw thro plate

Compression plating

• Compression through plate

- DC / LC-DC

• Compression with tension devise

Compression with external devise

Contouring Plates

• To fit anatomy of bone• Bending pliers• Weakens plate

Buttress Plate• Used when the fracture will only displace in one

direction. • Only useful in metaphyseal fractures • Applied so as to resist one deforming force

AO Organisation

☻Philosophies and techniques of treatment will change with time

☻ The philosophy that we exist to improve the care given to our patients will last forever

THANK YOU