1 Tension band principles topenlarge
The philosophy behind the tension band for the olecranon is that it converts tensile forces on the posterior side of the olecranon into compression forces at the joint line during flexion. The fixation is simple and inexpensive and works well if executed properly.
Multifragmentary fractures cannot be fixed with a tension band. In order to be able to use a tension band, the anterior (far) cortex cannot be comminuted and must provide a buttress to allow compression.
Choose a wire of sufficient strength to withstand the tensile forces generated in the figure-of-eight loop (1.0 mm). Positioning the K-wires as close to the joint while also penetrating the volar cortex is paramount.
Pearl: 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.
AO teaching video: Olecranon—transverse fracture 21-B1 tension band wiring
2 Reduction topenlarge
There is almost always a small spike on one of the fragment sides that exactly fits into a gap on the opposite fragment.
Reduce and hold the reduction of the transverse olecranon fracture with one or two small pointed reduction forceps.
Pearl: To prevent the reduction clamp from slipping on the distal fragment, a small drill hole can be drilled 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 as the drill tends to slide dorsally.
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 from medial to lateral. As the ulnar nerve is medial it is safer to introduce the wire from this side.
4 Insertion of the K-wires topenlarge
Using the drill guide, introduce the first 1.6 mm K-wire medially through the proximal end 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 the K-wire through both cortices.
Insert the drill guide over the first K-wire, and insert the second 1.6 mm K-wire parallel to the first one.
Check the position of both K-wires on the C-arm. If the position of wires and fracture reduction is good, pull both K-wires back approximately 1 cm.
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.
Note: Make sure that loop and wire twist do not lie too close to the wire hole to avoid unnecessary tension at the wire hole.
Placing the loops more proximal will allow a smaller incision when removing them after healing.
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, 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.
Note: Avoid excessive tensioning, especially in osteoporotic 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 pliers, bending iron and forceps, bend the proximal end of the K-wires 180 degrees.
Cut the K-wires leaving a bend of about 5-6 mm. Make a small cut in the triceps to allow burial of the K-wires. The K-wires are then driven home, sinking their curved ends into the bone in order to prevent backing out and skin irritation. Closing the small cut in the triceps over the K-wires will help prevent backing out of the wires.
Confirm fracture stability and range of motion, including supination-pronation. Exclude K-wire impingement of the radial ulnar joint. Final x-rays or image intensifier views should demonstrate good reduction and proper 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 7 cm.
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 over compress the fracture.
As the ulna has a slight bend distal to the metaphysis the long intramedullary screw can cause displacement when engaging the isthmus of the intramedullary canal distally.