1 Principles topenlarge
Triangle of stability
Stability of the distal humerus is based on a triangle of stability, comprising the medial and lateral columns, and the transverse condylar mass. In complete articular fractures, all 3 columns have to be restored.
2 Reduction and provisional fixation topenlarge
Fixation of small articular fragments
Although by definition, this is a simple articular fracture, in many instances, small articular fragments may be found.
In parallel plating it is customary to reduce and provisionally secure all of the fracture fragments, prior to plate application, using smooth K-wires.
3 Definitive plate and screw fixation topenlarge
Plate selection and contouring
Contoured 3.5 mm reconstruction plates, or precontoured plates, are selected for direct lateral positioning on the lateral column and direct medial positioning on the medial column.
These are usually placed slightly posteriorly and are always placed on top of the soft tissues - do NOT strip the medial and lateral columns.
The plates should extend distally enough to engage all fracture fragments and proximally enough so that 2 or 3 screws from each plate engage the proximal (shaft) fragment.
Drilling for distal screws
As many screws as possible are placed in each distal fragment.
Each screw goes through a plate hole.
Smooth K-wires the same size as the appropriate drill (e.g. 2.0 mm wire for 2.7 mm screw) can be manually inserted through the plate holes to ensure that the screws, once inserted, do not conflict: this also allows the drilling stage to be skipped.
The length of each of these K-wires must be known so that the appropriate screw length can be measured off the protruding wire, or the wire removed and the length of the pilot hole that it created measured using a standard depth gauge.
Distal screw application
Each of the smooth pilot K-wires is exchanged for its
4 Proximal plate fixation topenlarge
When there is solid bony contact across the articular and proximal fragments, compression is applied with pointed reduction forceps and eccentrically placed load screws, one column at a time.
Once the fixation is complete, all remaining K-wires are removed.
- When a column is comminuted it should be bridged and if necessary, because of missing bone fragments, bone grafted.
- When the reassembled condylar mass is short, and non-locking plates are used, long, distal-to-proximal, 3.5 mm column screws will enhance the stability of the fixation. These need to be inserted with great care in the presence of comminution of a column.