1 Introduction topenlarge
B1.3 and B3.3 fractures overlap
As partial articular fractures become more complex and multifragmentary, the B1.3 and B3.3 fractures start to overlap. B1.3 fractures feature coronal fracture lines that create separate capitellar and trochlear fragments. B3.3 fractures are often associated with impaction of the posterior part of the lateral column, and/or the posterior trochlea. These fracture types will therefore be considered together.
Apparent capitellar fractures
Most apparently isolated capitellar fractures are more complex than they initially appear.
Computed tomography - particularly 3D CT - can help define the fracture anatomy and facilitate planning of the surgery.
The “double arc” sign
Radiographs are insufficient
Sometimes the appearance is more complex, but it can be difficult to understand the fracture pattern on standard radiographs, particularly if a cast obscures the view.
Computed tomography, with 3-dimensional reconstruction in particular, is very useful for understanding apparently simple capitellar fractures that turn out to be more complex.
Lateral epicondylar fracture
Here it is apparent that the lateral epicondyle is fractured.
The posterior aspect of the lateral column is also abnormal.
In this image, it is apparent that the articular fragments may not fit, suggesting impaction of the posterior trochlea and particularly the lateral column.
Extension to the medial side
An end-on view shows the complexity, particularly on the lateral side.
Also, one can see a fracture - albeit very subtle - between the medial epicondyle and the medial trochlea.
3D CT evidence of impaction
Here the medial side fracture can be seen as well as what appears to be impaction (narrowing of the olecranon fossa). These injuries are very subtle, but were confirmed during operative exposure.
Choice of approach
The best approach to the distal humerus depends on the main fracture morphology. In very complex fracture situations the posterior approach, using an osteotomy of the olecranon, provides an excellent access.
For less complex fractures, a lateral approach can be chosen to access the articular segment of the distal humerus.
For capitellar fractures, a lateral approach should be chosen as it gives direct access to the fracture.
The following describes the use of a lateral approach.
2 Reduction topenlarge
Cleaning of the fracture site
The fracture surfaces are cleared of clot and debris.
Realignment of fragments
The fracture fragments are pieced together like a puzzle.
When the pieces do not fit
If the pieces do not fit properly, this is usually a result of impaction of the posterior aspect of the lateral column, and sometimes of the posterior trochlea.
Posterior view of impaction
A posterior view of the impaction of the posterior aspect of the lateral column.
Disimpact with an osteotome
If impaction is identified, this should be gently disimpacted with a fine osteotome used as a lever.
3 Provisional fixation topenlarge
The disimpacted fragments can be provisionally stabilized with smooth K-wires.
4 Definitive fixation (extensile lateral approach) topenlarge
Fixation of entirely articular fragments
Entirely articular fragments can be secured with buried headless screws, small threaded K-wires, or absorbable pins.
This illustration shows insertion of a headless double-pitch screw.
Repair of the lateral epicondyle
The lateral epicondyle can be provisionally fixed with a K-wire. Small epicondylar fractures may benefit from fixation with a tension band wire that incorporates the soft tissue attachments.
Use a large gauge needle to pass the wire through the soft tissues on the lateral epicondyle.
Tension wire fixation of lateral epicondyle
The wire is passed through a drill hole in the lateral column proximally, in a figure-of-8 fashion and tensioned to achieve stable fixation.
Plate fixation of lateral epicondyle
Larger partially articular fragments can be fixed with an additional plate and screws.
The final combined fixation.
5 Fixation via olecranon osteotomy topenlarge
Fractures that involve the posterior aspect of the trochlea, or of the medial epicondyle, may be best treated via an olecranon osteotomy.
An olecranon osteotomy provides exposure to the entire articular surface.
Mobilization of impacted fragments
The posterior trochlea is gently disimpacted using a fine osteotome as a lever. Care is taken to try to preserve some of the inherent stability.
The lateral column must also be disimpacted.
End-on view of the disimpaction.
Headless countersunk screws
Headless countersunk screws can be used to secure articular fragments that are large enough and of adequate bone quality.
Dedicated plates with many small distal screws can be used to engage the subchondral bone of the articular fracture fragments. Alternatively, standard reconstruction plates are used, as illustrated.
Medial and lateral plates were used here to stabilize a complex articular comminution.