1 General considerations top
Anatomical reduction and stable fixation of both fractures are desirable for 21-A3 fractures. Begin by exposing both fractures.
Usually, the ulnar fracture will be fixed first. Malreduction of the first of the fractures will usually impede reduction of the other. The specific fracture fixation is determined by the character of each fracture and is discussed below.
Rare type IV Monteggia fractures (complete dislocation of the radial head relative to capitellum) must be recognized, because both dislocation and fracture must be reduced.
Compression plate principles
In transverse fractures, compression can only be achieved using a preloaded plate. Slight overbending of the plate is necessary to ensure compression of the far cortex. Sequence of screw insertion:
- The first screw should be inserted in neutral position.
- A second screw is inserted eccentrically into the opposite fragment.
2 Reduction and preliminary fixation top
Cleaning the fracture site
Expose the fracture ends with minimal soft tissue dissection off the bone.
Remove hematoma and irrigate.
Reduction can be achieved by direct or indirect reduction techniques.
Reduce the fracture with the help of two small pointed reduction forceps...
...and provisonally fix it with two K-wires or reduction clamps.
Reduction with a plate
Fix the contoured and prebent plate with one screw to the proximal fragment. Then reduce the distal fragment against plate and proximal fragment by manipulation of the distal ulna, possibly aided by a clamp outside the fracture site. Final adjustment of the screw may affect reduction, and may be delayed until a screw is placed in the distal fragment.
In minimally displaced fractures this reduction might be achieved indirectly.
3 Plate preparation topenlarge
Use a six hole plate. Usually, three screws in each fragment provide sufficient stability.
The plate may be a small fragment (3.5 mm) dynamic compression plate (DCP), a limited contact dynamic compression plate (LC-DCP), or a locking plate (LCP) with conventional screws.
In osteoporotic bone there is an indication for the use of a an LCP in combination with locking head screws.
Contouring the plate
Contour the plate according to the surface anatomy of the ulna. Place a slight convex bend over the fracture to ensure compression of the opposite cortex.
Contour the plate with bending irons or bending press.
4 Creating compression topenlarge
Apply a 3.5 mm cortical screw in neutral position into the proximal fragment next to the fracture.
Insert a 3.5 mm cortical screw in eccentric position into the distal fragment, next to the fracture, creating compression across the fracture.
5 Finish fixation topenlarge
Insert the rest of the screws in neutral position.
An interim assessment of alignment, stability and range of motion is advisable after fixation of the ulna. Check results with image intensifier or x-ray.
6 Final assessment top
Finally, after fixing both radius and ulna, assess the range of motion in pronation, supination, flexion and extension. Fixation should be stable and crepitus or restricted motion should be absent. Radiocapitellar and ulnohumeral joints should remain located through a full range of motion.
Check results with image intensifier or x-ray.