Lag-screw fixation

The main goals of the surgery are to restore the length of the medial column without compromising the blood supply of the cuneiform.

The timing of surgery is influenced by the soft tissue injury and the patient's physiologic status. 

Medial and lateral external fixation (with a distractor device to restore columnar length) should be applied as soon as possible to stabilize the foot and decrease further injury to the soft tissues.

Temporary percutaneous K-wires can be used to reduce displaced fragments and are left as temporary fixation.

• Safe zones for pin insertion

The procedure is performed with the patient placed supine with the knee flexed 90°.

The percutaneous approach to the cuneiform may be used for screw fixation in nondisplaced or minimally displaced simple/noncomminuted fractures (ie, midbody stress fractures).

If a closed reduction cannot be performed, a dorsomedial approach is made directly over the fracture.

The fracture is entered directly and dealt with as necessary.

Insert the pointed reduction forceps through two small stab incisions placed dorsomedially and dorsolaterally.

Careful clamp placement prevents obstruction of lag screws.

Provisional fixation can be performed using K-wires. Be sure to place the K-wires so that they will not interfere with the subsequent screw placement.

Ensure that the joints are anatomically reduced. The reduction can be inspected under direct vision if the joint has been correctly distracted.

Otherwise, the articular surface can be palpated with an elevator inserted dorsally.

If the reduction cannot be inspected under direct vision, use image intensification. Remember that the resolution of the image intensifier may not be sufficient to appreciate small joint incongruities. If in doubt, get intraoperative x-rays.

Use an image intensifier to verify the appropriate screw length.

Insert the proximal lag screw according to the standard technique. In contrast to lag screws inserted in the diaphysis, these lag screws will typically not penetrate the far cortex, as this would damage the opposite articular surface. 

Afterward, insert a second lag screw in the same fashion.

• Insertion of cortical lag screws

If the bone is porotic, insert a washer under the screw head to prevent it from sinking into the bone.

The non-adherent antibacterial dressing is applied as a first layer. Sterile undercast padding is placed from toes to knee. Extra side and posterior cushion padding are added.

The foot should be immobilized for the first two weeks, which can be achieved using a three-sided plaster splint. The anterior area is left free of plaster to allow for swelling. Ensure that the splint’s medial and lateral vertical portions do not overlap anteriorly and that the splint does not compress the popliteal space or the calf.

The patient should be counseled to keep the leg on a cushion and elevated. Remember not to elevate the leg too much as it may impede the inflow. The foot’s ideal position is halfway between the waist and the heart when the patient is sitting. While seated, the foot should be on a cushion and elevated, but if badly swollen, the patient must be supine since elevating the foot while seated decreases swelling less effectively.

Avoid direct pressure against the heel during recumbency to prevent decubiti.

The OR dressing is usually left in place and not changed until the first postoperative visit at two weeks when x-rays are obtained once the dressing is removed. If any complication is suspected (eg, infection or compartment syndrome), the dressing must be split and, if necessary, removed to allow full inspection.

The strict non-weight bearing should be maintained until there is evidence of healing and any transfixion K-wires (6–12 weeks) or bridging devices (min 12 weeks) are removed.

Daily toe movement is encouraged.

Formal physical therapy should not begin in the early postoperative period.

A gastrocnemius release may need to be performed in cases with postoperative gastrocnemius contracture. This occurs more typically in the mid and hind-foot.