Locking plate fixation with/without lag screw of proximal articular fractures of the 1st–4th metatarsal

The principle of this procedure is first to reduce and fix the articular block. Anatomical reduction of the joint surface is essential to prevent chronic instability or posttraumatic degenerative joint disease. The articular block is then fixed to the shaft using a plate.

An alternative strategy is to simultaneously reduce and temporarily fix all components of the fracture, followed by definitive fixation. Typically the definitive fixation would start with screw fixation of the articular block.

Depending on the fracture pattern of the first metatarsal, the plate can be applied medially or dorsally to allow lag screw insertion through the plate, perpendicular to the fracture plane.

As a dorsal plate will cause less soft tissue irritation than a medial plate, some surgeons prefer dorsal plate application.

This illustration shows dorsal and medial plating for a complete articular fracture of the first metatarsal, where the articular component is in the sagittal plane.

This illustration shows dorsal and medial plating for a complete articular fracture of the first metatarsal, where the articular component is in the coronal plane.

For metatarsals 2–4, the plate can only be applied dorsally, and consequently, the fracture pattern may not always allow for lag screw fixation.

Expose the articular surfaces.

Visualization may be improved by longitudinal manual distraction.

For fractures involving the first metatarsal, a mini distractor may be helpful. Visualization may be improved by releasing the dorsal insertion of the extensor hallucis brevis or extensor digitorum brevis (EHB or EDB).

The extensor hallucis longus should be preserved.

Clean the fracture using a dental pick. Direct suction or irrigation is helpful.

The fracture edges are exposed, and the fragment mobility is assessed. Take great care to avoid further fragmentation. It is essential to maintain the vascularity of small fragments.

The extent of articular involvement is assessed, including separate osteochondral fragments.

If reconstruction of the articular surface is not feasible, a fusion of the joint should be considered.

Under direct visualization, the articular fragments are manipulated using a dental pick, small K-wires as joysticks, or a small periosteal elevator.

Small K-wires can be inserted across the fracture line for preliminary fixation.

Depending on fracture configuration, pointed reduction forceps may be used for reduction and preliminary fixation.

Be careful not to apply excessive force as this can lead to fragmentation. If possible, apply the reduction forceps so that the forces created by the forces are at right angles to the fracture line. This forceps placement helps in reducing the fracture and in applying compression.

Centrally impacted fragments in compression fractures are devoid of soft-tissue attachments and are therefore not reducible by ligamentotaxis.

Direct reduction is necessary.

The key to fixing compression fractures is restoring the joint surface to as close as normal as possible and supporting the reduction with bone graft and internal fixation.

Using a K-wire, or dental pick, the fragments are disimpacted and pushed towards the opposing bone, which is used as a template to ensure congruity of the articular surface.

Since the metaphyseal cancellous bone is impacted, a void may be created by its disimpaction.

This void jeopardizes the fracture in two ways:

• It is a very unstable situation in which the articular fragments may easily displace (collapse)
• The healing process is delayed

The bony defect under the fragments is filled with cancellous bone graft. The bone graft also helps keep the fragments in place when the screw fixation is performed.

Anatomical reduction of the joint surface must be checked under direct visualization and image intensification.

Length, alignment, and rotation of all metatarsals and joints must be maintained.

A 2.0 or 2.4 T-plate is typically used. The length of the plate should allow at least two points of fixation in the shaft.

Contour the locking plate to fit the bone surface of the metatarsal.

The articular component should ideally be fixed and compressed using lag screws. When a locking plate is indicated, compression can be achieved using the following sequence.

Insert a lag screw either outside or through any plate hole, including the locking holes.

Insert locking head screws into the articular block to secure the compression provided by the lag screw.

The locking head screw will also create a fixed angle between the articular block and the plate.

Replace the lag screw with a locking head screw (optional).

Adjacent bones and soft tissues may prevent the insertion of lag screws. The transarticular fracture component must be compressed during the fixation of the articular block to achieve stability of the articular surface.

Ensure anatomic reduction of the intraarticular component and compress the fracture using pointed reduction forceps.

If possible, insert K-wires for temporary fixation.

A 2.0 or 2.4 T-plate is typically used. The length of the plate should allow at least two points of fixation in the shaft.

Contour the plate to fit the bone surface of the metatarsal.

The plate is placed with the T-portion near the articular surface without interfering with the joint.

Ensure that the plate is centered on the long axis of the diaphysis

Insert the locking head screws into the articular block following standard techniques.

Careful contouring of a locking plate must be performed to prevent plate prominence or articular malreduction.

Reduce the articular block to the shaft and restore anatomical axial rotation, length, and angulation.

A periosteal elevator used as a lever may be helpful.

Alternatively, use a reduction forceps, dental pick, or a K-wire as a joystick as described above.

If there is any comminution in the shaft component, the fracture will shorten.

The length can be restored either by manual traction or a distractor.

A distractor will also maintain the length, whereas a manual distraction will not.

Use image intensification to confirm the reduction.

Use a small clamp to stabilize the fracture.

Using a small bone hook, apply traction to the plate to create compression at the fracture site before screw insertion.

Depending on bone quality, the articular block is fixed to the shaft using two 2.0 mm or 2.4 mm screws inserted in neutral mode.

The articular block is fixed to the shaft by inserting two 2.0 mm or 2.4 mm screws inserted in neutral mode.

Obtain x-rays to confirm length, rotation, angulation, and hardware placement.