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.
2. Patient preparation and approach
This procedure is normally performed with the patient in a supine position.
Multifragmentary diaphyseal fractures of the fifth metatarsal can best be approached through a lateral incision (see Lateral approach to MT5).
An open, direct reduction is done. Great care must be taken to preserve the soft-tissue attachments to the fragments. Reduction is achieved under direct vision by matching the fracture fragments to one another. A number of pointed reduction forceps are used to maintain the provisional reduction. At this point, an intraoperative x-ray may be helpful to check the accuracy of the reduction. The contralateral foot is often a useful aid in checking the alignment of Lelièvre’s parabola.
The plate must be contoured anatomically to the bone surface.
The plate is applied to the bone and is fixed both proximally and distally making certain, that the length, rotation and axial alignment have been restored. If possible, lag screws are used to secure compression between the fragments prior to the application of the plate. Lag screw(s) can also be inserted through the plate. This depends on the fracture configuration.
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.