1 Preliminary remarks topenlarge
Fracture assessment and decision making
In B3 type fractures, the palmar rim of the distal radius, at the radiocarpal joint, is sheared off, resulting in a partial articular fracture. There may be additional comminution. This is best demonstrated by CT scans.
The result of the injury is joint incongruity and palmar subluxation of the carpus. The treatment of choice is palmar buttress plating.
There are various plates available. The size of the palmar rim fragments will influence the choice of plate.
Plates with variable angle screw options may be useful in this situation.
Provisional reduction in displaced fractures
Reduction is achieved by applying longitudinal traction either manually or using Chinese finger traps.
The reduction is maintained by a temporary splint.
If definitive surgery is planned, but cannot be performed within a reasonable time scale, a temporary external fixator may be helpful.
2 Associated injuries topenlarge
Median nerve compression
If there is dense sensory loss, or other signs of median nerve compression, the median nerve should be decompressed.
Associated carpal injuries
These injuries may be associated with shearing injuries of the articular cartilage, scaphoid fracture and rupture of the scapholunate ligament (SL). Every patient should be assessed for this injury. If present, see carpal bones of the Hand module.
These injuries may be accompanied by avulsion of the ulnar styloid and/or disruption of the DRUJ. If there is gross instability after the fixation of the radial fracture, it is recommended that the styloid and/or the triangular fibrocartilaginous disc (TFC) is reattached (see A1.1). This is not common in simple fractures, but may occur with some high energy injuries.
The uninjured side should be tested as a reference for the injured side.
It may not be possible to assess DRUJ stability until the fracture has been stabilized (as described below).
3 Reduction and plate fixation topenlarge
Hyperextension of the wrist
Reduce the fracture by hyperextension of the wrist over a pad.
Perfect anatomical reduction can be achieved by direct manipulation of the distal fragment using a dental pick or a fine hook.
Create a buttress
Ensure that the plate is contoured so that its distal limb exerts even pressure over the fragment or fragments of the palmar rim of the radius. The distal end of the plate should end at the anatomic watershed zone of the distal radius.
Attach the plate to the distal radial shaft, using an appropriate screw through the oblong plate hole. Before fully tightening it, check the plate position using intraoperative imaging, adjusting the position of the plate as necessary so as to provide an optimal buttress effect.
Now tighten the first screw and insert a second screw. Check adequate buttress pressure on the palmar rim fragment(s).
Insertion of distal screws
Confirm reduction using image intensification.
Secure the distal fragment(s) with at least two screws through the appropriate distal holes, as dictated by the fracture pattern. The screws must not penetrate the dorsal radial cortex.
If a plate is selected with threaded holes in the distal limb, then locking head screws are used.
Pearl: Plate selection
For a B3.3 fracture comprised of a small distal articular rim fracture, a palmar plate which directs the very distal screws proximally may be applicable.
As the screws are placed in a very subchondral manner, there is a high risk that there may be some inadvertent penetration of the joint. Special care must be taken to exclude this with imaging.
As the plate is so distal, flexor tendon irritation is common and so this plate usually has to be removed.
Pearl: Suture fixation
For very small fragments, it may be easier to obtain strong hold by suturing the palmar ligaments and capsule to the plate.
4 Assessment of Distal Radioulnar Joint (DRUJ) top
Before starting the operation the uninjured side should be tested as a reference for the injured side.
After fixation, the distal radioulnar joint should be assessed for forearm rotation, as well as for stability. The forearm should be rotated completely to make certain there is no anatomical block.
The elbow is flexed 90° on the arm table and displacement in dorsal palmar direction is tested in a neutral rotation of the forearm with the wrist in neutral position.
This is repeated with the wrist in radial deviation, which stabilizes the DRUJ, if the ulnar collateral complex (TFCC) is not disrupted.
This is repeated with the wrist in full supination and full pronation.
In order to test the stability of the distal radioulnar joint, the ulna is compressed against the radius...
...while the forearm is passively put through full supination...
If there is a palpable “clunk”, then instability of the distal radioulnar joint should be considered. This would be an indication for internal fixation of an ulnar styloid fracture at its base. If the fracture is at the tip of the ulnar styloid consider TFCC stabilization.