Soft-tissue integrity is an essential prerequisite for open reduction and plate fixation of metatarsal shaft fractures.
Should there be compromise of the surrounding soft tissues, percutaneous pinning may be a safer option.
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. Patient preparation and approach
This procedure is normally performed with the patient in a supine position.
One or multiple diaphyseal metatarsal fractures or dislocations can best be approached through appropriately placed dorsal incision(s) (see Dorsal intermetatarsal approach).
Manual traction on the toe, as illustrated, will usually regain correct length and rotational alignment of the distal metatarsal segment.
The reduction may be held with pointed reduction forceps, applied perpendicular to the fracture planes.
Care should be taken to preserve soft-tissue attachments to the metatarsal, as stripping the intrinsic muscles away removes local blood supply and interferes with healing.
Intraoperative x-rays are helpful to confirm normal alignment of metatarsal length and head location.
Temporary K-wires may also be used for temporary reduction, with fixation to adjacent metatarsal(s), penetrating both cortices of the adjacent metatarsal(s). This will hold the fracture out to length.
Simple spiral or oblique fractures
A simple spiral fracture of a metatarsal if displaced and if it requires reduction is best secured with lag screw fixation.
A single lag screw is not enough and must be protected with a plate.
A transverse fracture requires compression-plate fixation.
Multifragmentary fractures are fixed with bridge plates as shown in the following steps.
The plate is applied to the dorsal surface of the metatarsal. This is generally straight, requiring only slight plate contouring.
Multifragmentary fractures in order to preserve their blood supply are bridged with a plate which is fixed to the proximal and distal fragment and will maintain their length and their proper axial alignment.
Clinical example: Plate fixation of fractures of the first to third metatarsal bones.
A sterile dressing is applied and the patient is immobilized in a boot or in a below-knee cast. If the state of the soft tissues is precarious, a padded bandage should be applied initially, and the limb should be maintained elevated until the swelling has subsided and healing of the soft tissues without further problems can be anticipated. The foot is then immobilized either in a boot or in a below-knee cast. The advantage of the boot is that it can be easily removed for inspection of the wound and for regular exercises and mobilization of the joints.
Weight bearing is delayed until such time as the wound is healed. The sutures are removed 2 weeks postoperatively and graduated weight bearing is started. The degree of loading of the extremity is determined by the severity of the injury and the stability of the fixation achieved. Early loading is important but not at the expense of loss of fixation. Intermittent elevation of the foot and extremity should be continued until such time as the swelling has subsided.
For percutaneous K-wire fixation
Weight bearing in a heel-wedge shoe is permitted. The K-wires are removed in the clinic at six weeks, at which point a flat postoperative or hard-sole shoe is permitted as tolerated.
X-rays are taken at 6 weeks postoperatively to assess union and the integrity of the fixation. The resumption of the use of normal footwear is guided by the clinical signs and x-ray evidence of union.