AO Plates & Their Application

Plates Aplications in Osteosynthesis

• Straight Plates

• Special Plates

• Angle Blade Plates

The 3 main groups of plates

• Protection or neutralization plates

• Buttress Plate• Compression plate• Tension band plate

Function of plates

Protection or neutralization plate

A plate used to protect a lag screw

Buttress PlateButtress Plate

A plate used to support a bone fragment/s

Compression Plate

The Plate is used to exert compression in the direction of the long axis of the bone

Tension Band PlateTension Band PlateA tension band is a device which exerts a force equal to but opposite in direction to the bending force

Large Fragment Plates

4.5mm Semi-Tubular Plate

• Originally designed to used as a tension band plate on radius, ulna and tibia

• Good rotational stability is achieved due to the edges that dig into the bone.

• Axial compression can be achieved if the screw is placed eccentrically on each side of the fracture

• 2 to 12 holes

Advantages of the 4.5mm Semi-tubular Plate

• The plate hole allows for deep penetration of the screw head into the cortex which has a risk of splitting the cortex. This can be prevented by enlarging the cortex.

Disadvantage of the 4.5mm Semi-tubular Plate

DCP – Dynamic DCP – Dynamic Compression PlateCompression Plate

The plate hole allows for self compression and a congruent fit between screw head and plate hole at different angles of inclination. Design based on 2 “cylinders”.


The plate hole design allows the plate to fulfil different plate

functions, eg compression,tension band, neutralization and buttress plating


Advantages of the DCP Plate

• 25 longitudinal and 7 sideways angulation

• Placement of screw in neutral position without danger of distraction of fragments.

Advantages of the DCP Plate

• Insertion of a load screw in any plate hole.

• Screw may be inserted in the buttress position in articular areas where a buttress plate is required.

Advantages of the DCP PlateAdvantages of the DCP Plate


After one load screw has been used in each main fragment, (1mm displacement) the horizontal track allows for a further 1.8mm of “gliding”.


A second load screw can therefore be placed in the next hole creating a further 1mm of compression. The first screw must be slightly loosened before the second screw is inserted.


Compression of individual fragments can be achieved in comminuted fractures.

Notches on underside of both ends of the plate for the tension device.


End holes accept 6.5mm cancellous screws.

Narrow 4.5mm DCP Plate

• Designed to be used on the tibia and occasionally on the radius or ulna.

Narrow 4.5mm DCP Plate

• Enlarged mid section for placement over the fracture.

• 2 – 16 holes

Broad 4.5mm DCP Plate

• Designed to be used on femur and humerus

• Thicker and wider than the narrow DCP

Broad 4.5mm DCP Plate

• Enlarged mid section for placement over the fracture.

• 6 – 18 holes.

• Staggered holes to prevent longitudinal fissuring of the bone.

LC-DCP, Limited Contact Dynamic Compression Plate

• A further development to the DCP with the same indications.

• Same hole size as the DCP, 8.5mm.

Top View

Bottom View

Advantages of the LC-DCP Plate

• Evenly distributed undercuts reduce contact between bone and plate. This reduces the damage to the blood supply and allows for the formation of a small callus bridge.

• 3 positions of screw placement – Neutral, load & buttress.


• A constant degree of stiffness is created along the axis of the plate due to the enlarged screw holes and the plate under cuts.No stress concentration occurs at the holes when the plate is exposed to bending.

• No enlarged mid section


• The plate holes are evenly spaced which permits easy placement of the plate.

• Symmetrical plate holes, compression either side.


• 40 longitudinal and +/- 7 sideways angulation

4.5mm Reconstruction Plates

• As these plates can be bent in 2 planes, they designed for use in the pelvic area.


• The plate should not be bent more than 15 at any one point.

• The oval holes allow for self compression.

Pelvic Plate

• 2 & 4 hole Narrow LC-DCP/DCP plates also used to treat Symphyseal ruptures

Narrow & Broad Lengthening Plates

• These plates are designed for stabilizing lengthened bone.


• Narrow used on the tibia & broad on the femur.

• Plates have an enlarged mid section without any holes.

• Shaft is similar to a narrow & broad DCP respectively.


• The round holes accept 4.5mm cortex screws and the end holes 6.5mm cancellous screws.

• Compatible with the tension device.


• Narrow plates are available in 4, holes at either end of the plate.

• Broad plates are available in 4 or 5 holes at either end of the plate.

Special 4.5mm Plates

• These are shaped to conform to the specific anatomical locations in the metaphysis.

• They are applied according to the same principals as the straight plates ieCompressionNeutralization or Buttress

T-Plates

• Designed to be used as buttress plates on the medial aspect of the tibial plateau.

• Can also be used on the proximal humerus and distal tibia and femur

T-Plates• Also used on the proximal

humerus for a large head fragment.

• The head accommodates 6.5mm screws.


T-Plates• Elongated hole in the shaft

for lag screw application and temporary fixation and adjustment.

• 3, 4, 5, 6 & 8 holes

T & L Buttress Plates

• Designed to be used as buttress plates on the humeral head lateral aspect of the tibial plateau.

• Have a double bend which contours to the lateral side of the proximal tibia.

T & L Buttress Plates• L-Plates are available in left &

right to avoid disturbing the fibula.

• The head accommodates 6.5mm screws.


T & L Buttress Plates• Elongated hole in the shaft for lag

screw application and temporary fixation & adjustment.

• T-Plates are available in 4, 5 & 6 holes.

• L-Plate is available in 4 holes only.

Spoon Plate

• Designed as an anterior buttress for distal tibial joint fractures (pilon).

Spoon Plate

• Experience has shown that the plate is too bulky for this application and is now indicated for metaphyseal non unions of the tibia.

• The plate is available in 5 & 6 holes.

Lateral Tibial Head Buttress Plate

• Designed to be used a buttress plate on the lateral aspect of the tibial plateau with proximal diaphyseal involvement.


• Have an expanded and shaped head.

• The round holes in the thinner head accommodate 6.5mm screws.



• Elongated hole in the shaft for lag screw application and temporary fixation & adjustment.

• Plates are available in 5, 7 & 9 holes in the shaft and for both left and right tibia.

Distal Femoral Buttress Plate

• These plates are used for comminuted fractures in the distal femur.

• Shaft is similar to a broad DCP & holes are staggered.


• Have an expanded and shaped head.

• The round holes in the thinner head accommodate 6.5mm screws.



• Plates are available in 7, 9, 11, 13 & 15 holes in the shaft and for both left and right femurs.

Cobra Head Plate

• These plates are designed for arthrodesis of the hip.

• Shaft is similar to a broad DCP & holes are staggered.

Cobra Head Plate• Have an expanded and shaped

head.

• The round holes in the head accommodate 4.5mm cortex screws.


Cobra Head Plate

• Plates are available in 8, 9, 10 & 11 holes in the shaft.

Hook Plate

• These plates are designed for stabilizing of the greater trochanter of the femur.(after distal transportation of the GT with intertrochanteric osteotomy)

Hook Plate• Shaft is similar to a broad DCP.

• The 2 round holes accept 6.5mm screws.


• Plates are available in 4 holes.

Small Fragment Plates

LC-DCP/DCP

• Indicated for radius and ulna fractures.

• Same principals as large fragment LC-DCP/DCP plates

• Available from 2 to 20 holes.

1 Third Tubular Plate

• Indicated for fractures of the fibula, lateral malleolus, metatarsals & metacarpals. Also used on the distal ulna and the olecranon.

1 Third Tubular Plate

• Compression is exerted by eccentric positioning of the screws.

• Available from 2 to 12 holes.

3.5mm straight & curved Reconstruction Plates

• As these plates can be bent in 2 planes, they designed for use in the pelvic area.


• The plate should not be bent more than 15 at any one point.

• The oval holes allow for self compression.

Small T-Plate

• Indicated for fractures of the distal radius (volar aspect). Also olecranon, distal tibia & lateral clavicle.

Small T-Plate


• Available from 3 to 6 holes with either 3 or 4 holes in the head.

Small Oblique T-Plate

• Indicated for fractures of the distal radius (dorsal aspect).

• Can be used left or right.

Small Oblique T-Plate


• Available in 3, 4 & 5 holes with 3 holes in the head.

Cloverleaf Plate

• Indicated for distal intra-articular tibia & proximal humerus fractures.

Cloverleaf Plate


• Available in 3 to 6 holes with 6 holes in the head.

Calcaneal Plate

• Fractures of the calcaneus.

• Available in 60 & 70mm lengths.


Calcaneal Plate

• Fractures of the calcaneus.

• 9 hole plate and 4 holes in the arm.


Clavicular Hook Plate

• Indicated for lateral clavicular fractures and acromion joint separations.

• 4 & 6 holes with 15 or 18mm hook depth.

• Left & right plates.

AO Plates & Their Application

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