1 Preliminary Remarks topenlarge
A B2.1 type fracture is a partial articular fracture of the distal radius, with a single, dorsal shearing fracture fragment. The fracture fragment may be small and located very close to the dorsal rim (representing osseous avulsion of the dorsal extrinsic ligaments), or it may involve a significant proportion of the articular surface and allow dorsal subluxation of the carpus.
These fractures are usually reduced and stabilized with dorsal plate (applied in buttress mode). Occasionally, external fixation in combination with K-wires or lag screws may be used.
These fractures may be associated with scapholunate interosseous ligament injury.
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 topenlarge
Open reduction is achieved via a dorsal approach, combined with a limited dorsal arthrotomy. The arthrotomy allows monitoring of the articular surface reduction and assessment of the scapholunate interosseous ligament.
If necessary, use a periosteal elevator to disimpact and elevate the dorsal fragment.
Provisional K-wire fixation
Insert a K-wire to hold the fragment provisionally.
Confirm reduction using image intensification.
4 Plate positioning and contouring topenlarge
Many plates are available for this application, some with locking screws. The most recently designed plates have variable angle locking screws. Locking screws are particularly helpful for small fragments of osteoporotic bone.
Because of the shape of the dorsal distal metaphysis, the plate may need to be adapted to fit the bone surface and the proximal limb may require some torsional adaptation.
If the plate being used has fixed angle locking screws, there is a risk that the screws may penetrate the joint. To prevent this, the distal limb of the plate must be bent to ensure the screws are parallel to the joint surface.
Pitfall: Screw hole distortion
Avoid contouring the plate through the locking holes, otherwise the locking head screw might not fit any more.
The longitudinal limb of the plate should rest between the second and third extensor compartments. Lister’s tubercle may be trimmed in order to provide a flat surface for the transverse limb of the plate.
5 Plate fixation topenlarge
Insert a nonlocking, standard screw through the oblong plate hole, long enough to engage the opposite cortex. Do not fully tighten it yet.
Confirm the reduction and plate position using image intensification. If necessary, adjust the plate position until it is as distal and as central as possible. If the provisional K-wire conflicts with the optimal plate position, the plate can be slipped over the wire.
Tighten the screw. The K-wire may then be removed.
Insert distal screws
Screws are then inserted through the distal plate holes.
Confirm screw position
With image intensification, confirm that the distal screws have not penetrated the articular surface. In order to have a view in line with the articular surface, the beam should be angled 20º from the true lateral.
Insert proximal screws
Insert the proximal screws, which should penetrate the palmar cortex.
6 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.