1 General considerations 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.
Comminuted fractures of the metatarsals may be aligned and stabilized with percutaneous K-wire fixation.
Percutaneous pinning of the foot will increase stability, maintain alignment and hasten resolution of swelling. When soft tissue swelling is sufficiently resolved, reduction of comminuted metatarsal fractures may be performed with bridge plating if there is sufficient bone stock proximal and distal to the fractures.
The plates may extend across the TMT and intercuneiform joints for additional stability.
2 Patient preparation topenlarge
This procedure is normally performed with the patient in a supine position.
3 Reduction topenlarge
These injuries usually are open allowing for direct open reduction of the associated fractures after appropriate debridement. Reduction is obtained with traction.
If the injury is closed, then fluoroscopy is used with traction.
4 K-wire fixation topenlarge
Occasionally if soft tissues are unacceptable for open reduction, then K-wire fixation alone may be used both temporarily and definitively.
The K-wire is inserted into the distal phalanx of the toe, just plantar to the nail bed, down the central axis of the toe crossing what is left of the DIP, PIP and MTP joints. The K-wire for each metatarsal must reach stable proximal bony fixation.
This image shows x-rays of a crushed foot before and after K-wire fixation (with plate fixation of first MT).
5 ORIF: plate fixation topenlarge
Once swelling has resolved in the foot, comminuted 1-4 MT fractures can be approached from the dorsum of the foot over the first and third web space (see Dorsal approach to the first metatarsal and Dorsal intermetatarsal approach).
The fifth MT fracture can be approached with a lateral incision (see Lateral approach to the 5th metatarsal).
This image shows a postop picture of approaches to first and second metatarsal base with the dorsomedial incision and approaches to the third and fourth metatarsal base with the dorsolateral incision.
Plates of sufficient length (2.4 mm or 2.7 mm) VA T-fusion plates or alternatively 1/3rd tubular or semi-tubular plates of sufficient length may be utilized to bridge the fracture site. The plates may be contoured if needed.
At least 2-3 screws should be placed proximal and distal to the fracture site. Proximally, the plate may cross the TMT and cuneiform joints, taking care that the screws do not enter the joints. Bicortical fixation is preferred.
This image shows postoperative x-rays of third, fourth and fifth metatarsal fractures treated with ORIF.
6 ORIF: mesh plate fixation topenlarge
For more extensive comminuted forefoot and midfoot fractures, plating of the medial and lateral columns of the foot can salvage a stable plantigrade foot. This can be accomplished by mesh plating of the medial and lateral columns.
After soft-tissue swelling has resolved, the foot may be approached with medial and lateral column incisions.
For the lateral column incision, a dorsolateral approach to the cuboid may be utilized and extended distally along the lateral aspect to the fifth MT.
For the medial column incision, the medial approach to the MT1 is utilized.
Once both columns are exposed, alignment of the foot is confirmed. Plantar bony prominences should be reduced.
Mesh plates may be cut and contoured to the columns and 2.7 mm locking screws inserted using the variable angle locking guides and 2.0 mm locking drill bits. The bone tunnels are measured, and the appropriate length 2.7 mm locking screws inserted.