1 Preliminary remarks top
Management of 21-A3 fractures
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.
Bridge plating principles for extraarticular ulnar fractures
Bridge plates must be fixed securely to the two main fragments. The intermediate fracture zone is left untouched. Anatomical reduction of the intermediate fragments is not necessary but alignment, rotation and length of the bone must be restored.
Direct manipulation of the intermediate fracture fragments risks disturbing their blood supply. If the soft-tissue attachments are preserved, and the fragments are relatively well aligned and stable, indirect bone healing is predictable.
2 Preliminary reduction topenlarge
Reducing a multifragmentary proximal ulnar fracture may be difficult. Reduction can be achieved with a small distractor as shown, or an external fixator with minimal exposure and manipulation of the fracture zone. This is difficult to do with manual traction alone.
Overall alignment of the proximal ulna may be restored with an appropriately contoured plate, fixed proximally with one screw and positioned over the distal fragment.
3 Choice of implant topenlarge
3.5 mm DCP, reconstruction plate, LC-DCP, LCP or a specific proximal ulna prebent plate can be used.
As bridge plating spans a long section of the bone, the length of the implant has to be chosen accordingly. The longer the fracture zone, the longer the plate to be used.
A locked plate with locking head screws is the preferred choice in osteoporotic bone.
4 Plate insertion options top
Bridge plates in the proximal ulna can be inserted through an open exposure with minimal soft-tissue damage. In open bridge plating, it is important to preserve soft-tissue attachments to the fracture fragments.
A bridge plate may be applied to medial, lateral, or posterior surfaces of the proximal ulna. The choice depends on other injuries, soft-tissue condition and surgeon’s preference.
Bridge plating can be done with a minimally invasive approach, which requires fluoroscopic monitoring. In minimally invasive surgery, a bridge plate is applied through one proximal and one distal incision, just wide enough for the plate. Control of reduction may be more difficult than with an atraumatic open technique.
In healthy bone, it is not necessary to fill all screw holes proximal and distal to the fracture zone. However, in osteoporotic bone it is safer to use all plate holes outside the fracture zone, or to use an LCP. Multiple screws add torsional stability and decrease the risk of failure.
5 Plate application topenlarge
Plate application in the proximal fragment
Apply the properly contoured plate to the proximal fragment, so that it is correctly aligned with the ulnar axis. When the plate fits satisfactorily against the proximal segment, it can be attached provisionally with a single screw.
While the plate is held manually against the bone, the screw is inserted. Sometimes it is helpful to clamp the plate to the proximal fragment of the ulna with a bone forceps.
In the lateral view the plate must be parallel to the longitudinal axis of the ulna. If alignment is satisfactory, apply a second screw to secure the plate proximally in this correct position.
Alignment and fixation of the distal fragment
Once the plate is satisfactorily fixed proximally, bring the distal fragment into alignment against the plate.
Often the plate can be held manually against the bone and a first distal screw is inserted after rotation and length are restored.
Sometimes it is helpful to clamp the plate to the bone with a bone forceps as shown. Carefully pass the forceps close against the bone during application in order to avoid injury to adjacent nerves.
6 Finish fixation topenlarge
If alignment is satisfactory, add a second distal screw and reconfirm alignment. At this time, the plate is attached to the ulna with two screws in the proximal, and two screws in the distal fragment.
Use at least three bicortical screws in each main fragment. In both major fragments, place the first screw as close as practicable to the fracture, and the second at the end of the plate.
Confirm reduction, plate position, and screw length under image intensification. Then proceed with treatment of the radial fracture. Occasionally, with A3.2 fractures, a simple radius fracture may easily be fixed anatomically. In this situation, its fixation might be done first to aid reduction of the ulnar fracture.
Beware of penetrating the joint with a screw in the proximal fragment.