1 Preliminary remark topenlarge
B1 type fractures are partial articular fractures involving the radial styloid.
In B 1.2 fractures there is a multifragmentary fracture. This can occur as a result of shear forces and compression and are frequently associated with carpal and radiocarpal ligament injuries.
K-Wires and cannulated screw fixation is a treatment option, if fragment specific plates are not available.
B1.2 fractures may also involve one or more separate, impacted fragments of the scaphoid facet.
A CT scan is advisable for preoperative assessment and planning.
Cannulated / conventional lag screws
If available, cannulated screws would be the preferred choice. If cannulated screws are not available, conventional lag screws may be used. Care should be taken that the K-wire placement does not interfere with screw insertion.
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
Use a periosteal elevator to disimpact joint fragments and, if necessary, derotate the radial styloid fragment. It is very important to make sure that the large radial styloid fragment is not malrotated.
A dorsal arthrotomy is recommended to check the accuracy of the articular reduction.
4 Fixation with K-Wires /cannulated screws topenlarge
Provisional guide wire fixation
Insert a K-Wire through the most distal point of the tip of the radial styloid to hold the large radial styloid fragment provisionally.
Add a second K- wire, inserted parallel to the radial joint surface, to hold the reduction of the impacted articular fragment(s).
Confirm reduction using image intensification.
Confirm reduction and K-wire position using image intensification
Confirm reduction and the position of the transverse guide wire using an image intensifier, with the beam angled 20º from the true lateral.
Filling the void (optional)
If there is a defect in the metaphyseal bone as a result of the disimpaction of the articular fragments, the void can be filled with autogenous cancellous bone.
If cannulated screws are not available, the K-wires may be bent and buried under the skin.
Fixation with lag screws
Partially (or fully – in case of comminution) threaded lag screws (cannulated screws, if available) may be used for fixation.
When inserting the transverse screw over its guide wire, make sure that it does not penetrate the sigmoid notch and enter the distal radioulnar joint.
Do not overly compress the radial styloid fragment when inserting the oblique screw, in order to avoid displacing the fragments.
Image intensifier control of screw positions and fracture reduction is mandatory.
The guide wires are now removed.
5 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.