Basic technique – hybrid stem

Provisional reduction of a comminuted fracture may be provided by cerclage wire or sutures.

The appropriate plate for bridging fixation may be applied and provisionally fixed proximally and distally, taking care not to obstruct the implantation of a planned humeral component. Provisional monocortical screws are recommended.

Pearl: Preoperative planning is needed to determine where the tip of the humeral implant, and therefore the cement mantle and cement restrictor, will reach, so that adequate plate length and screw distribution is achieved distal to the new implant.

The canal is prepared using manual reamers of increasing size, until an appropriate diaphyseal fit is obtained.

Pitfall: Excessive torsion may disrupt the provisional fracture fixation. This can be avoided by incremental increase in the size of the reamers, and by taking care not to advance the reamer while applying torque.

$Humeral shaft periprosthetic fracture – the canal is prepared$

Pitfall: If fracture fixation has been performed, ensure that the reamer does not engage with the unicortical screws during canal preparation.

In the case of reamer engagement with the screws, the following options can be considered:

Replace the screw with a shorter screw, or a screw with a blunt tip.
Downsize the diameter of the humeral component.

$Humeral shaft periprosthetic fracture – ensure that the reamer does not engage with the unicortical screws during canal preparation$

Distal segment cementing technique

If the fracture pattern is not amenable to anatomic reduction, a modified cementing technique must be used for the distal segment to prevent cement interfering with bone healing.

$Humeral shaft with comminuted periprosthetic fracture - implant removed.$

Cementing technique

A cement restrictor is used to prevent distal filling of the medullary canal with cement. The position of the restrictor is guided by preoperative planning. Ideally, the humeral component should project approximately four or five centimeters distal to the fracture to ensure that distal cement fixation is adequate for primary stability.

A long cement introducer is used to backfill the distal medulla up to the level of the fracture.

Pearl: Accurate cementation is facilitated with an image intensifier.

Pitfall: Extrusion of cement at the fracture site must be avoided to prevent damage to local nerves and blood vessels. The radial nerve and profunda brachii vessels are particularly at risk.

$Humeral shaft with comminuted periprosthetic fracture – cement is injected$

Implantation of humeral component

The definitive implant is introduced slowly, correcting for rotational alignment and height before fully seating the implant.

Any cement that has been extruded from the fracture site must be removed, so that:

Nerve and blood vessel injury is avoided
Fracture healing is facilitated

$Humeral shaft with comminuted periprosthetic fracture – the definitive implant is introduced$

Definitive fixation of the fracture

With the implant securely cemented into the distal segment definitive fixation of the fracture can be completed using cerclage cables, wires or sutures, and screws as appropriate.

$Humeral shaft with comminuted periprosthetic fracture –definitive fixation of the fracture$