Authors of section

Authors

Renato Fricker, Matej Kastelec, Fiesky Nuñez, Terry Axelrod

Executive Editor

Chris Colton

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Plate fixation

1. Introduction

A typical site for metacarpal base fractures is the fifth metacarpal. Most of these fractures are comminuted and impacted, and are often associated with carpo-metacarpal fracture dislocations. Additional dorsal shearing fractures of the hamate may be present. These fractures are usually fixed with plates, or K-wires in the case of small fragments, and may need bone grafting.

A typical site for metacarpal base fractures is the fifth metacarpal.

CT scans are very helpful to determine the number, size and position of the fragments.

These fractures are usually fixed with plates, or K-wires in the case of small fragments, and may need bone grafting.

Simple fractures

Depending on the fracture geometry, simpler fractures can be treated with lag screws (e.g. extensor carpi ulnaris tendon avulsion fractures), or with T-, Y- or L-shaped plates.

Depending on the fracture geometry, simpler fractures can be treated with lag screws ...

Dislocation of the 4th metacarpal

Fractures of the fifth metacarpal base may be associated with a carpo-metacarpal dislocation of the fourth ray. In that case, the fourth metacarpal is reduced first and usually stabilized with transfixion K-wires.
Occasionally, there is a subluxation of the 3rd metacarpal, or even the 2nd metacarpal, and any combination of additional fractures can be seen.

Fractures of the fifth metacarpal base may be associated with a carpo-metacarpal dislocation of the ...

2. Approach

For this procedure a dorsal approach to the fifth carpo-metacarpal joint is normally used.

plate fixation

3. Reduction

Restore length

Apply axial traction on the finger, either manually or with a finger trap. A small external fixator can be used, with K-wires inserted into the hamate and the distal metacarpal, preliminarily to fix the reduction.
Capsulotomy is needed to check the reduction of the articular fragments if the joint capsule is not already ruptured.

Apply axial traction on the finger, either manually or with a finger trap.

Reduce fragments

Use a dental, pick, a periosteal elevator, or small K-wires to reduce the fragments. Insert small K-wires for preliminary fixation of these articular fragments. Occasionally, these K-wires are inserted percutaneously; make sure not to injure the dorsal sensory branch of the ulnar nerve.
In case of a bone defect, bone graft from the distal radius is used to fill the void.
Check reduction using image intensification.
If the hamate is uninjured, its articular surface can be used as a template for restoring the articular surface of the metacarpal base.

Use a dental, pick, a periosteal elevator, or small K-wires to reduce the fragments. Insert small K-wires for preliminary...

Check rotational alignment

Turn the hand over and flex the fingers passively to check for correct rotational alignment.
The image on the right shows rotational malalignment of the middle finger (“scissoring”).

Turn the hand over and flex the fingers passively  to check for correct rotational alignment.

Accompanying hamate fracture

In the case of a shearing fracture of the hamate, reduce this fragment first and fix it with a lag screw.

In the case of a shearing fracture of the hamate, reduce this fragment first and fix it with a lag screw.

4. Plate preparation

Plate selection

Depending on fragment size, a 2.0 mm, or, more frequently, a 1.5 mm plate is used.
T-, L- or Y-shaped plates can be used and the choice depends on the geometry of the fracture.
At least 2 screws should be inserted into the diaphyseal fragment.

Depending on fragment size, a 2.0 mm, or, more frequently, a 1.5 mm plate is used.

Contouring of the plate

The plate must be contoured exactly to fit the surface of the metacarpal, including any necessary twisting.

The plate must be contoured exactly to fit the surface of the metacarpal, including any necessary twisting.

5. Fixation

Apply the plate

Position the plate exactly so that the articular fragments can be fixed using screws through the proximal plate holes. Often, it is not possible to insert a screw into each fragment. Small fragments should be supported by adjacent large fragments, or bone graft.
Be careful to ensure that the screws do not perforate the joint surface.

Be careful to ensure that the screws do not perforate the joint surface.

Buttress small fragments

If necessary, small K-wires can be inserted transversely just deep to the subchondral cortical bone, in order to buttress these small fragments.

If necessary, small K-wires can be inserted transversely just deep to the subchondral cortical bone, in order to buttress ...

Drill for first screw

Begin fixation with the most critical articular fragment.
Drill carefully in order not to displace the fragments.
Measure for the length of the screw.

Drill carefully in order not to displace the fragments.

Insert first screw

Insert the first screw without completely tightening it.
Confirm the reduction and correct screw position using image intensification.

Insert the first screw without completely tightening it. Confirm the reduction and correct screw position.

Fix plate to diaphysis

With the first screw in place, align the plate along the shaft. Usually, the plate is now fixed to the diaphyseal fragment with one screw through its most distal hole. Tighten this screw.

With the first screw in place, align the plate along the shaft.

Insert second proximal screw

Drill the second main articular fragment. Avoid penetration of the joint surface and interference with the first screw. Measure screw length with a depth gauge.
Insert the screw and alternately tighten the two screws in the articular fragments

Drill the second main articular fragment.

Further fragments

If additional large metaphyseal fragments need fixation, insert screws through the plate, or insert an independent lag screw.
If needed, use additional bone graft to fill any defect.

If additional large metaphyseal fragments need fixation, insert screws through the plate, or insert an independent lag screw.

Insert second diaphyseal screw

Insert the second and, if possible, a third screw into the diaphyseal fragment and tighten them.

Insert the second and, if possible, a third screw into the diaphyseal fragment and tighten them.

Complete osteosynthesis

When the fixation is completed, remove the external fixator and K-wires, other than those needed to buttress small articular fragments.

When the fixation is completed, remove the external fixator and K-wires, other than those needed to buttress small articular ...

6. Complex fragmentation

Bridging fixation with ExFix

If fixation can not be performed with screws and plates, stabilization can be achieved with an external fixator bridging the fracture zone from the hamate to the metacarpal.
This allows for the restoration of correct length and rotational alignment.

If fixation can not be performed with screws and plates, stabilization can be achieved with an external fixator bridging ...

Bridging fixation with internal fixator

This can also be performed using a bridging plate as an internal fixator with screws inserted into the hamate and the diaphysis of the metacarpal.
The plate is removed when the fracture has completely healed after about 4 months.

This can also be performed using a bridging plate as an internal fixator with screws inserted into the hamate and the ...

7. Postoperative splint

A removable splint may be applied at the end of the operation, with the hand in an intrinsic plus (Edinburgh) position.
In compliant patients with stable internal fixation the splint can be removed after any swelling has receded. It may be worn at night for a longer period as this may increase patient comfort.

screw fixation

While the patient is in bed, use pillows to keep the hand elevated above the level of the heart, in order to reduce swelling.

screw fixation

For ambulant patients, put the arm in a sling and elevate to heart level.

Instruct the patient to lift his hand regularly above the head, in order to mobilize the shoulder and elbow joints.

screw fixation

Follow up

See the patient after 2 days for a dressing change. After 10-12 days, remove the sutures and confirm radiologically that no secondary displacement has occurred.
Additional x-rays are taken 4 weeks after internal fixation. Usually, the fracture line will still be visible.
X-rays are repeated after 8 weeks to assess union.
Strengthening exercises and manual work are allowed according to clinical and radiological evidence of bone healing.

Functional exercises

As pain and swelling recede, early, active, controlled digital range of motion exercises gently progress.
The importance of mobilization must be emphasized to the patient and rehabilitation should be supervised by a physical therapist.

nonoperative treatment