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.
Minimally displaced fractures with the hallux in good alignment are treated nonoperatively with buddy taping and a rigid sole shoe.
Displaced fractures may be associated with first MTPJ dislocation. Reduction of the articular surface and alignment of the first MTPJ and its associated soft tissues are important in treating this injury.
Pearl Look for damage to the plantar plate by assessing sesamoid position on an AP radiograph. Check whether they are spread apart or not.
2. Patient preparation
This procedure is normally performed with the patient in a supine position.
3. Closed reduction and K-wire fixation
May attempt closed manual reduction and percutaneous pinning. However, as this is an intraarticular fracture anatomic reduction of the metatarsal head is preferred.
If anatomic reduction cannot be obtained, an open reduction should be performed.
Once alignment of the fragment is obtained, a 1.6 mm K-wire may be placed percutaneously perpendicular to the fracture plane, a second parallel wire may be placed to prevent rotation.
Reduction is confirmed with intraoperative fluoroscopy or radiographs.
4. Open reduction internal fixation
If unable to reduce the fracture with manual reduction, a medial approach to the hallux may be utilized and the fracture disimpacted and reduced with a Freer elevator, and the fracture held in reduction with pointed reduction forceps.
If the fracture is complicated by soft-tissue or tendon injury a dorsal approach may be preferred.
A 2.0 mm or 2.4 mm lag screw may then be placed perpendicular to the fracture plane, after drilling the appropriate gliding and thread holes.
For fractures on the lateral aspect of the head, the lag screws can be placed percutaneously.
A second lag screw may be placed for long oblique fractures. If one is dealing with osteoporotic bone, then a washer under the head of the screw is useful to prevent the head from sinking.
Final fixation with two small lag screws securing the intraarticular fracture.
After percutaneous pinning immobilize the foot in a flat, rigid sole shoe until the K-wires are removed at six weeks.