Simple fractures of the proximal ulna are often associated with proximal radial injuries. Usually, the ulnar fracture will be fixed first. Malreduction of the ulna will impede reduction of the radius.
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.
Prior to reduction, 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 provisionally fix it with two K-wires or reduction clamps.
Reduction with a plate
Fix the contoured and pre-bent 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.
Plate length should be sufficient to place, usually, three screws in each fragment.
The plate may be a small fragment dynamic compression plate (3.5 DCP), or limited contact dynamic compression plate (LC-DCP), or locking plate (LCP) with conventional screws. More recently, use of 2.7 LCP has been reported.
Note: In osteoporotic bone, a LCP with locking head screws should be used, after insertion of a conventional lag screw through the plate.
Contouring the plate
Place a slight convex bend over the fracture to ensure compression of the opposite cortex.
Contour the plate with bending irons or bending press.
Make a small cut in the triceps tendon to slide the plate under.
Apply plate and hold it against the bone with a bone clamp or one or two fingers.
Apply a cortical screw in neutral position into the proximal fragment next to the fracture. The screw is inserted until it stabilizes the plate, but not fully tightened.
Insert a cortical screw in eccentric position into the distal fragment, next to the fracture, until it compresses the far cortex.
Both screws are then tightened completely.
Insert the rest of the screws in neutral position and remove the K-wires.
After fixation of the 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.