Lag-screw fixation

Partial articular fractures require anatomical reduction and may be fixed with lag screws if the size of the fragment allows.

The reduction can be assisted with arthroscopy if skill and equipment are available.

The joint may collapse if there is impaction or comminution while the lag screw is tightened. In this case, plate fixation should be considered for chondral support.

This fracture type may be associated with metacarpophalangeal (MCP) joint dislocation. In this case, the dislocation must be manipulated, and any interposed soft-tissue structures removed.

Note: Axial traction may permit soft tissue to be interposed. This obstructs relocation and should therefore be avoided.

$Lag-screw fixation with two screws of a partial articular fracture of the metacarpal head$

Percutaneous vs open reduction and fixation

Percutaneous reduction and fixation may be performed.

The advantages are:

Shorter operation time
Less soft-tissue damage
Faster mobilization

This treatment option needs some skills and experience and special reduction forceps to avoid impingement of swollen soft tissue (atraumatic technique).

These reduction forceps allow to hold the reduction at the planned screw placement, and drilling and screw insertion. There is no need for additional K-wire fixation or reduction forceps placement.

If a percutaneous reduction is not achievable, the treatment can be changed to open surgery.

$Percutaneous lag-screw fixation of a partial articular fracture of the metacarpal head$

For this procedure, a dorsal approach to the MCP joint can be used.

Dorsal approach to the 2nd metacarpophalangeal joint

Closed reduction

Reduce the fracture indirectly by manual traction.

The articular reduction can be confirmed with arthroscopy.

$Closed reduction of a partial articular fracture of the 5th metacarpal head$

Special reduction forceps designed for percutaneous fixation may be used to hold the reduction.

$Holding the closed reduction of a partial articular fracture of the metacarpal base with reduction forceps$

Open reduction

For more accurate reduction, use small pointed reduction forceps gently to manipulate the fracture. Application of excessive force can result in fragmentation.

Confirm reduction with an image intensifier.

Note: Anatomical reduction is important to prevent chronic instability or posttraumatic degenerative joint disease.

$Holding the reduction of a partial articular fracture of the metacarpal base with reduction forceps$

Preliminary K-wire fixation

Preliminarily fix the fragments by inserting a K-wire. Be careful to place it so it will not conflict with later screw placement.

$Holding the reduction of a partial articular fracture of the metacarpal base with a K-wire avoiding the planned screw tracks$

Stability evaluation

Confirm reduction with an image intensifier and check the joint stability by flexion and extension. This should show congruent movement compared with the adjacent joints.

Planning for screw insertion

Each lag screw must be inserted perpendicularly to the fracture plane.

Do not insert screws too close to the fracture apex or the subchondral bone. A minimal distance from the fracture line, equal to the screw head diameter, must be observed.

The screw insertion should avoid conflicts with the MCP ligaments.

The screw length needs to be adequate for the screw to penetrate and purchase in the opposite (trans) cortex.

$Screw placement not close to the fracture apex and with minimal distance to the fracture line equal to the diameter of the screw head$