1 Tension band principles topenlarge
The tension band converts tensile forces on the posterior side of the olecranon into compression forces at the joint line. In the olecranon, the figure-of-eight wire loop acts as a tension band during flexion of the elbow.
Multifragmentary fractures cannot be fixed with a tension band. In order to be able to use a tension band, the anterior cortex cannot be comminuted and must provide a buttress to allow compression.
The figure-of-eight wire loop lies on the posterior surface of the olecranon and acts as a tension band when tightened.
Choose a wire of sufficient strength to withstand the tensile forces generated in the figure-of-eight loop (1.0 mm).
Pearl - Very proximal fracture or small avulsion fracture of the triceps insertion from the olecranon
Depending on the size of the proximal bone fragment, it can either be excised and the tendon reinserted, or it can be reinserted and stabilized with an additional interfragmentary screw or tension band wiring.
2 Reduction topenlarge
Reduce and hold the reduction of the transverse olecranon fracture with small pointed reduction forceps.
To prevent the reduction clamp from slipping on the distal fragment, a small drill hole can be predrilled in the distal fragment before applying the clamp.
3 Prepare wire insertion topenlarge
Approximately 40 mm distal to the fracture line and 5 mm from the posterior cortex, drill a hole through the ulna with a 2.0 mm drill, using a sharp drill guide.
Wire preparation and insertion
Prepare a 1.0 mm wire by making a loop approximately one third along its length.
Insert the shorter segment of the wire through the drilled hole.
4 Insertion of the K-wires topenlarge
Using the drill guide, introduce the first 1.6 mm K-wire medially through the head of the olecranon. Aim the drill towards the anterior cortex, passing as close as possible to the joint. Leave enough space on the lateral side for the second K-wire.
Drill both cortices. Just after drilling the anterior cortex, drill the K-wire back approximately 1 cm. This is necessary as the proximal, bended ends of the K-wires will finally be hammered into the bone and the distal ends should not protrude into the anterior soft tissues.
Cut the K-wire obliquely 2 cm from the bone using the wire cutters.
Insert the drill guide over the first K-wire, and insert the second 1.6 mm K-wire parallel to the first one.
After drilling of the anterior cortex, again drill back for 1 cm.
Cut the second K-wire in the same way as the first one.
5 Wire fixation topenlarge
The small pointed reduction forceps can now be removed.
Pass the long segment of the wire (bearing the loop) in a figure-of-eight configuration beneath the triceps tendon around the protruding ends of the K-wires.
Unite the two wires with a little twist.
Make sure that loop and wire twist do not lie too close to the wire hole in order to avoid unnecessary tension at the wire hole.
Tightening the wire
Loosely prepare the wire twist ensuring that each end of the wire spirals equally - the twist should not comprise one spiral around a straight wire.
Cut the wire ends short.
The slack is then taken up by further twisting. Repeat this until the desired tension is achieved. Both loops must be tightened at the same time and in the same direction, in order to achieve equal tension on both arms of the wire.
By tightening the twist and the loop with two pliers simultaneously, the two fragments are drawn together such that the fracture is placed under compression.
Avoid excessive tensioning, especially in osteopenic bone.
Prevent later soft-tissue irritation
Trim the twisted wire and turn both ends towards the ulna/olecranon in order not to irritate the soft-tissues later.
Sinking the K-wires
With the help of a plier, bending iron and forceps, bend the K-wires through 180 degrees. The K-wires are then driven home, sinking their curved ends into the bone in order to prevent backing out and skin irritation.
Confirm fracture stability and range of motion, including supination-pronation. K-wires may impinge on the radius. Final x-rays or image intensifier views should demonstrate satisfactory reduction and hardware position.
Pearl - Intramedullary screw
As an alternative, one intramedullary screw or two intramedullary K-wires may be used instead of the two K-wires penetrating the anterior cortex.
Introduce a 6.5 mm cancellous screw with a 32 mm thread and a washer inside the canal. The screw should cross the fracture site at least 7cm.
Choose the screw long enough to purchase in the inner cortex of the diaphyseal area. Usually, a screw of 10-12 cm length is appropriate.
Make a stab incision through the triceps tendon insertion to place drill and screw. When tightening the screw make sure not to overcompress the fracture.
Intramedullary K-wires have a greater risk of backing out.