Plating with precontoured periarticular locking plates provides angular-stable fixation and is the most commonly used method of distal humeral fracture fixation.
Dorsolateral plates should be considered in the presence of coronal-shear articular fragments.
Some dorsolateral plates have a lateral extension or tab that allows screws to be placed from lateral to medial as well as posterior to anterior in the articular segment.
Together with a medial plate, they form a perpendicular plating construct.
Parallel vs perpendicular plating
Both techniques—if applied using the correct principles—provide sufficient stability for fracture union. The decision to use either construct should be based on the fracture pattern and be individualized to each case.
If periarticular locking plates are not available and reconstruction plates need to be used, a parallel plating construct may be more appropriate than a perpendicular plating construct.
Principles of fracture compression in the distal humerus
In general, there are two sites where fracture compression should be achieved through solid bony contact across the fracture:
In the articular block between the articular fragments
At the supracondylar level
Note: Most nonunions occur at the supracondylar level.
2. Plate characteristics
These plates usually have smaller locking holes in the distal part to capture the articular fragments and larger locking/nonlocking holes proximally to address the metadiaphyseal segment/fragments.
3. Screw characteristics
For application of the plate to the bone, three screw types may be used:
Locking screws (variable angle or fixed angle)
Combination of different screw types
If compression across a fracture segment is to be applied, this should be performed before adding locking screws in the same segment.
Perren S, Babst R, Lambert S, et al. The issue of mixing principles in internal fixation. Pros and cons. ICUC Newsletter. 2015 Nov;3. Available at: www.icuc.net/static/media/9.563f04cf.pdf. Accessed November 3, 2020.
4. Plate length
The plate length should allow placement of at least three screws proximal to the most proximal fracture line.
If there is metaphyseal fracture comminution, a longer plate should be selected for bridge plating.
Select a plate long enough so that the resulting construct respects the principle of balanced fixation. This includes considerations of screw type, screw density and direction, and plate working length.
When using two plates, it is preferable to end the plates at different levels to avoid a stress riser.
When applying a longer dorsolateral plate, identify and protect the radial nerve to avoid injury as it crosses the spiral groove of the humerus. See also the information about neurological protection and handling.
5. Plate contouring
Modern anatomical periarticular plates are designed to match the anatomy of most patients. Therefore, contouring is not usually required.
If the plates do not fit the distal humerus following reduction, confirm first that the reduction is anatomical under image intensification.
In some instances, contouring may still be required.
Avoid bending the plate through screw holes as this will weaken the plate and deform locking holes, which may hinder screw locking.
6. Plate positioning
Place the plate to the dorsolateral aspect of the distal humerus beneath the triceps.
The plate needs to be applied distal enough for the distal screws to engage the capitellum. Proximally the plate sits on the posterior aspect of the humeral shaft.
Provisionally fix the plate to the bone with forceps or K-wires.
Pitfall: Avoid placing the plate too distally; otherwise, there may be impingement against the radial head in terminal elbow extension.
7. Insertion of first proximal screw
Provisionally fix the plate to the bone with a cortical position screw through one of the combiholes proximal to the fracture zone.
8. Insertion of distal screws
The distal screws can be locking or metaphyseal screws.
Locking screws are typically used to provide angular-stable fixation.
Metaphyseal screws are used to provide intraarticular fracture compression.
Variable angle locking screws
The distal screws are locking screws. They form a fixed angle construct with the plate.
Insert these screws in a fixed or variable angle mode depending on the fracture pattern.
Pitfall: Variable angle screws offer adaptable fixation in the articular block, but there is a risk of transgressing the olecranon fossa. Intraoperative imaging may be required to confirm accuracy of screw position.
Screws should be long enough to engage fragments on the opposite side to the plate.
The distal screws must be unicortical to avoid violating the anterior articular surface of the capitellum, or the coronoid fossa.
Option: lateral tab
The lateral tab gives the possibility to address coronal and sagittal plane fractures with one plate.
Insert screws, depending on the fracture pattern.
The goal is to insert at least two screws (locking or metaphyseal) long enough to engage the fragments on the opposite side.
Pitfall: articular penetration of screws
Screws through the articular surface will cause damage to the radial head and/or the greater sigmoid notch of the ulna.
Screws in the olecranon fossa will cause obstruction of the olecranon tip in extension resulting in pain and loss of motion.
Use image intensification and/or direct visualization to ensure correct screw position.
9. Fixation of articular block
Interfragmentary compression of simple articular fracture
If there is a simple fracture of the articular block, apply extrinsic or intrinsic compression by one of the following options.
Extrinsic compression applied by forceps and maintained with a locking screw through the plate
Intrinsic compression applied by insertion of a transverse lag screw separate to the plate. The screw may be a partial threaded cancellous screw or an overdrilled fully threaded cortical screw. ...
... Add a locking screw through the articular block.
Intrinsic compression applied by insertion of a metaphyseal lag screw through the plate
Insertion of posteroanterior locking screws
To lock rotation of the lateral articular fragment, insert at least one posteroanterior locking screw.
When drilling prevent penetration of the far cortex.
Take care to measure the screw length correctly to avoid penetration of the capitellar articular surface.
Fixation of multifragmentary articular fractures
Reconstruct the articular block with K-wires.
Place locking screws through the plate into the articular block to maintain reduction without applying excessive compression with forceps. The locking screws are used as positioning screws to maintain reduction.
Avoid overcompressing the articular fragments in multifragmentary articular fractures. This may result in collapse of the fragments and narrowing of the articular block, which can lead to maltracking of the joint with the ulna.
Priority should be given to reconstructing the medial trochlear ridge and lateral column.
10. Fixation of supracondylar fracture
When the metaphyseal component of the fracture is simple, compression may be applied between the articular block and the humeral shaft.
Loosen the initially placed cortical screw.
Use forceps applied between the articular block and the metadiaphyseal segment to achieve compression.
Retighten the screw.
Insert further cortical or locking head screws into the proximal plate holes as needed.
Compression may also be achieved by inserting a further proximal cortical screw eccentrically in a combihole.
Before tightening this screw, loosen the first bicortical one so the plate may slide for compression of the fracture.