Intramedullary screw fixation of olecranon osteotomy

Introduction

An intramedullary screw can be used to fix an osteotomy.

It is useful to predrill the screw track before performing the osteotomy to maximize efficiency and accuracy.

Intramedullary screw fixation of olecranon osteotomy

Implant size

A minimum size of 4.5 mm partially threaded cancellous screw with washer should be used. The screw should be long enough to purchase in the inner cortex of the ulna diaphysis. Usually, a screw of 8–10 cm length is appropriate.

Entry point

It is critical when choosing the entry point of the screw to respect the native anatomy of the proximal ulna. There are apex dorsal angulation and varus angulation of the proximal ulna of varying degree within patients.

The entry point of the screw should be offset from the center of the olecranon tip to account for the varus bow and prevent gapping at the osteotomy site.

Pitfall: Incorrect entry point and screw angle will lead to premature engagement of the screw tip with the ulna cortex. This leads to gapping of the osteotomy as the screw is driven distally.

Incorrect entry point and screw angle will lead to premature engagement of the screw tip with the ulna cortex. This leads to gapping of the osteotomy as the screw is driven distally.

Incision of triceps tendon

Make a stab incision through the triceps tendon insertion to place drill and screw.

Drilling and tapping

Use the appropriately sized drill to predrill for the intramedullary screw. Tap the drill hole to minimize the risk of fracture during screw placement.

Tapping the drill hole for the intramedullary screw

Reduce and hold the osteotomy with pointed reduction forceps to apply compression.

Make sure that the reduction restores perfectly the predrilled hole.

Pearl: To prevent the reduction forceps from slipping on the distal fragment, a small hole can be drilled in the distal fragment before applying the forceps.

Reduce and hold the osteotomy with pointed reduction forceps to apply compression.

Insert the planned screw with a washer.

Checking results

Confirm stability of the fixation and range of motion, including supination/pronation. Check for screw head impingement within the olecranon fossa with elbow extension. Final x-rays or image intensifier views should demonstrate good reduction and proper hardware position.