1 Introduction topenlarge
Take care when approaching an apparently simple capitellar fracture. These are often complex.
The majority extend into the lateral trochlea and should not be considered for nonoperative treatment.
Many fractures also involve a fracture of the lateral epicondyle and impaction of posterior aspect of the lateral column, or the posterior trochlea.
Computed tomography with 3D reconstructions helps to identify these fracture characteristics, and facilitates planning.
This module addresses coronal plane fractures of the capitellum and part of the trochlea, without fracture of the lateral epicondyle, or of the posterior aspect of the distal humerus.
These fractures can be repaired with buried headless screws, or alternatively, with screws that are inserted from posterior to anterior.
Screw fixation is straightforward using cannulated screws, but can also be undertaken with non-cannulated screws if cannulated screws are not available.
If non-cannulated screws are being used, provisional fixation should be achieved with K-wires which are then exchanged carefully, one at a time, for the definitive screws.
2 Open reduction topenlarge
The origins of the extensor carpi radialis longus and extensor carpi radialis brevis (ECRB) are elevated from of the anterior aspect of the humerus, along with the brachialis.
The interval between the ECRB and the extensor digitorum communis (EDC) is split distally. Care is taken not to go posterior to the midpoint of the radial head, in order to protect the lateral collateral ligament.
The capsule is incised, if not already ruptured.
The fracture fragment should be apparent in the anterior aspect of the joint.
Clean the fracture site
Clean out the fracture by removing blood clots, loose pieces of bone, and any interposed tissue. Inspect the joint to ensure that no additional intraarticular fracture component was missed when examining the imaging.
Reduce the fracture. If the anterior exposure is in any way limited and digital reduction is not possible, a K-wire "joystick" and small pointed reduction forceps can be used.
Monitor fracture reduction by realigning the metaphyseal and articular fracture lines.
3 Fixation topenlarge
Insert the guide wires across the fracture site, where the planned screw tracks will be. Be sure to use the correct diameter guide wires for the chosen screw size.
Insertion of screws
Measure the screw length of the guide wire, using the appropriate depth measuring device.
Overdrill the wire
Insert the wire deeper so that it is not dislodged during drilling.
Drill the pilot hole for the screw to the appropriate depth, using the cannulated drill bit placed over the guide wire.
Insert the chosen screw over the wire, then remove the guide wire. Complete the insertion of the first screw, before inserting the second screw.
The muscle interval is then closed.