1 Indications top
Soft-tissue integrity is an important pre-requisite for open reduction and plate fixation of metatarsal neck fractures.
If soft-tissue conditions do not allow for open reduction and plate fixation, percutaneous pinning should be considered as an alternative either as a temporary or definitive form of fixation.
2 Principles topenlarge
Proper alignment of the metatarsal heads is a critical goal in restoring the pathomechanics of the forefoot. On the AP view, a normal curved “cascade” (Lelièvre’s parabola) appearance, symmetric with the other foot, is mandatory. See illustration.
This ensures that the normal length of the metatarsal is restored.
It is also critical to restore the metatarsals in their axial or horizontal plane so that in the axial or tread view all the metatarsal heads are on the same level.
Any malalignment particularly flexion will recreate focally high pressure during the stance phase and toe-off and will result in pain and subsequent callus formation.
Note that for the first ray, it is the sesamoids rather than the first metatarsal head, that bear weight, and therefore one must look at the sesamoid level in establishing the alignment in the axial or horizontal plane of the first metatarsal.
3 Approach and reduction topenlarge
One or multiple subcapital metatarsal fractures or dislocations can best be approached through appropriately placed dorsal incision(s) (see Dorsal intermetatarsal approach).
Manual traction through the toe is generally sufficient to correct length and rotational alignment of the distal segment.
The reduction is held with pointed forceps, applied perpendicular to the fracture plane. Temporary K-wires may also be used.
Protect the metatarsal head from damage when applying the clamp.
Intraoperative x-rays may help to confirm appropriate alignment.
4 Fixation topenlarge
Screw purchase in the metatarsal head can be tenuous. For this reason, a plate with a larger distal buttress surface like the L- or the T-plate is usually used for improved fixation.
Fixation in the distal fragment can also be improved by the use of locking screws which provide angular stability.
Consider fixation of a simple fracture with a lag screw.
If the fracture is transverse use the L- or the T-plate as a compression plate.
Make sure that the screws are not so long that they protrude below the plantar bone surface or articular cartilage.
If the fracture is multifragmentary maintain your reduction with temporary K-wire fixation.
Secure permanent fixation with the L- or T-plate which will be used then in a bridging mode.
Alternative: K-wire fixation
For simple fractures, manual reduction and percutaneous fixation with K-wires may also be considered. The K-wire is inserted percutaneously into the distal phalanx across the DIP and PIP joints, along the central axis of the toe.
The head is manually reduced and the K-wire is advanced across the MTP joint into the metatarsal shaft. The K-wire can either exit the metatarsal shaft or enter the proximal cuneiform.
Alternatively, the corresponding toes may be elevated and the K-wire may be inserted plantar to the toe, up the central axis of the fractured metatarsal.