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Authors of section


Khairul Faizi Mohammad, Brad Yoo

Executive Editors

Richard Buckley, Markku T Nousiainen

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Lag-screw fixation

1. General considerations

Goal of surgery

The goal of surgery is to reconstruct the joint, and to ensure joint stability and medial column length.

Timing of surgery

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


timing of surgery

2. Screw selection

For the procedure, a range of screws can be utilized:

  • Cannulated screws
  • Non-cannulated screws
  • Headless compression screws

We will here demonstrate the use of cannulated and non-cannulated screws.

Cannulated, non-cannulated, and headless compression screw

3. Patient preparation and surgical approach

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

Supine position knee flexed 90°

A limited dorsomedial approach is made directly over the fracture without peripheral dissection and undermining, maintaining the blood supply.

The fracture is entered directly and dealt with as necessary.

Limited incision for a dorsomedial approach to the navicular and cuneiform

4. Reduction

Use a K-wire or small clamp to reduce the avulsed fragment to the main fragment. Verify the reduction fluoroscopically.

Take care not to place the clamp (or K-wire) where the lag screw will be inserted.

Reduction of a navicular avulsion fracture with forceps

5. Fixation using cannulated screws

K-wire insertion

When cannulated screws are used, insert the guidewire perpendicular to the fracture line under image intensification to temporarily secure the fixation.

Care must be taken to avoid tarsonavicular joint penetration.

K-wire insertion for cannulated lag screw fixation of a navicular avulsion fracture

Screw insertion

Insert a cannulated lag screw according to the standard technique. A washer is typically used.

A headless screw can also be inserted following the standard technique of headless screw insertion.

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.

Cannulated screw insertion for fixation of a navicular avulsion fracture

6. Fixation using non-cannulated screws

Temporary fixation

A K-wire may be inserted to fix the fragment temporarily.

Pearl: It is advantageous to maintain compression with the reduction clamp to secure the reduction during drilling.

Drilling for lag screw fixation of a navicular avulsion fracture

Screw insertion

Insert a lag screw with a washer according to the standard technique.

Remove the K-wire.

Lag screw fixation of a navicular avulsion fracture

7. Aftercare


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.

Immobilization of the foot with a three-sided plaster splint


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.

Patient seated with the foot immobilized in a plaster splint and the leg elevated on a cushion

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.