Executive Editor: Chris Colton

Authors: Renato Fricker, Matej Kastelec, Fiesky Nuñez, Terry Axelrod

Metacarpals - Intraarticular head fracture

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Glossary

1 Introduction top

Metacarpal head fractures may be single, but are often multifragmentary. enlarge

Fracture configuration

Metacarpal head fractures may be simple, but are often multifragmentary.
The degree of displacement and the number of fragments may be difficult to judge on standard x-rays. CT scans can be helpful in these situations.


The fractures can usually be treated with screw fixation. enlarge

Screw fixation

The fractures can usually be treated with screw fixation. If the fragments are sufficiently large, screws are inserted in an antegrade manner, without perforating the articular cartilage. In smaller fragments, retrograde fixation has to be performed, and the screws are inserted through the articular cartilage. Care must be taken to bury the screw head underneath the cartilage.
As an alternative to standard screws, small headless screws can be used if the fragment is sufficiently thick.
In severely impacted fractures, bone graft, harvested from the distal radius, may be necessary.

2 Reduction top

The articular fragments are manipulated using a dental pick, small K-wires, or a small periosteal ... enlarge

Reduction tools

The articular fragments are manipulated using a dental pick, small K-wires, or a small periosteal elevator.
Small K-wires can also be used for preliminary fixation. Depending on fracture configuration, pointed forceps may be useful for reduction.


In impacted fractures, the articular surface is reduced, and the bony defect under the fragments is filled with bone graft ... enlarge

Impaction

In impacted fractures, the articular surface is reduced, and the bony defect under the fragments is filled with bone graft from the distal radius. This also helps to keep the fragments in place when the screw fixation is performed.


Anatomical reduction of the joint surface must be checked under direct view and image intensification. Maximally flex the ... enlarge

Anatomical reduction is mandatory

Anatomical reduction of the joint surface must be checked under direct view and image intensification.
Maximally flex the MP joint in order to gain a view of the palmar aspect of the metacarpal head.

3 Large fragment fixation - antegrade top

If the fragments are large enough to allow sufficient purchase, antegrade screws are preferred, in order not to penetrate ... enlarge

If the fragments are large enough to allow sufficient purchase, antegrade screws are preferred, in order not to penetrate the joint surface.
Drilling must be performed very carefully in order not to perforate the articular cartilage. If necessary, drilling is performed under image intensification. Drill at low speed and without exerting pressure.
Make sure that the screws do not conflict with the collateral ligament.
As the screws do not engage the opposite cortex, they are inserted as position screws, i.e. they are threaded in both fragments.


If the fragments extend to the metaphyseal region, bicortical lag screws can be used. enlarge

If the fragments extend to the metaphyseal region, bicortical lag screws can be used.


Measure for correct screw length using the appropriate depth gauge. enlarge

Measure for length

Measure for correct screw length using the appropriate depth gauge. When measuring, be careful not to displace the reduced fragments. If a position screw is planned, choose a slightly shorter screw length than measured to avoid fragment displacement.
Countersinking is only performed when the entry point of the screw is in the diaphyseal region.


Carefully insert the screw without displacing the reduced fragments. enlarge

Screw insertion

Carefully insert the screw without displacing the reduced fragments. Confirm using image intensification.
Insert additional screws in a similar manner.

4 Small fragment fixation - retrograde top

Small fragments are best stabilized with retrograde screws that are inserted through the articular cartilage. enlarge

Small fragments are best stabilized with retrograde screws that are inserted through the articular cartilage. Choose the smallest possible screw diameter to minimize the damage to the joint surface. Headless screws – if available in very small sizes – have the advantage that they can be inserted deeper into the fragment without protruding.
Depending on the fracture configuration and available screw lengths, the opposite cortex may be engaged. Standard screws are usually inserted as position screws.


Drill carefully in order not to displace the fragments. Measure for correct screw length with a depth gauge... enlarge

Drilling and measuring

Drill carefully in order not to displace the fragments. Measure for correct screw length with a depth gauge. When measuring, be careful not to displace the reduced fragments.


Be careful not to injure the thin subchondral cortex. enlarge

Countersinking the articular cartilage

When standard (headed) screws are used, the cartilage is countersunk to facilitate burial of the screw head. Be careful not to injure the thin subchondral cortex.


Carefully insert the screw without displacing the reduced fragments. Make sure that the screw head is buried in the ... enlarge

Screw insertion

Carefully insert the screw without displacing the reduced fragments. Make sure that the screw head is buried in the articular cartilage and does not protrude into the joint.
Insert additional screws using a similar technique.

v1.0 2008-11-08