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Authors of section

Authors

Fabio A Suarez, Aida Garcia

Executive Editor

Simon Lambert

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Intramedullary screw fixation

1. General considerations

Introduction

Transverse extraarticular neck fractures may be fixed with an intramedullary headless screw (3.0 or 4.0 mm), either ante- or retrogradely. The retrograde insertion needs thorough planning to avoid MCP joint problems.

The antegrade insertion needs at least 10 mm of bone stock in the distal fragment to get optimal fracture compression.

This screw acts like an intramedullary nail.

Intramedullary screw fixation of an extraarticular transverse fracture of a metacarpal head

Prerequisites for intramedullary screw fixation

The diameter at the isthmus of the intramedullary canal should be at least 3 mm wide in AP and lateral views.

To allow for fracture compression, the length of the screw should be long enough so that the threads at the tip only engage in the far fragment.

To achieve optimal stabilization, the screw should be long enough and with a diameter filling the intramedullary canal.

Longitudinal crosssection of a metacarpal showing the intramedullary space

2. Patient preparation

Place the patient supine with the arm on a radiolucent hand table.

Patient positioned supine with the arm on a radiolucent hand table

3. Reduction

Reduce the fracture preliminarily by flexing the MCP and proximal interphalangeal (PIP) joints to 90° and using the proximal phalanx to push up the metacarpal head (Jahss maneuver).

Final reduction is performed with the guide wire and screw.

Reduction of an extraarticular transverse fracture of a metacarpal head with the Jahss maneuver

4. Retrograde screw insertion

Guide wire insertion

Hold the MCP joint in 90° flexion.

Incise the skin and extensor tendon and identify the dorsal part of the metacarpal head.

Insert the guide wire dorsally into the head in line with the intramedullary canal under image intensification until the tip reaches the base.

Confirm correct rotational alignment.

Intramedullary screw fixation of an extraarticular transverse fracture of a metacarpal head - Guide wire insertion in a retrograde fashion

Screw insertion

Predrill the entry point and if needed the medullary canal. This creates a track for screw insertion and reduces the risk of deviation during screw insertion.

Select a screw with the appropriate diameter and length using the depth gauge provided. The thread of the tip should engage the isthmus distal to the fracture line.

Insert the screw over the guide wire until the head is fully entered into the metacarpal and the fracture is compressed.

Confirm reduction and correct screw placement with an image intensifier.

Confirm correct rotational alignment of the finger.

Intramedullary screw fixation of an extraarticular transverse fracture of a metacarpal head – Screw insertion in a retrograde fashion

5. Antegrade screw insertion

Identifying the entry points

Identify the base of the metacarpal.

Incise the skin at the base of the metacarpal to expose its dorsal aspect.

Protect the extensor carpi radialis longus/brevis during the wire and screw insertion to the 2nd/3rd metacarpal.

Protect the extensor carpi ulnaris during the wire and screw insertion to the 5th metacarpal.

Entry points for antegrade intramedullary screw fixation of transverse metacarpal fractures

Guide wire insertion

Create an entry point with a drill to pass the guide wire into the bone.

Pearl: Use a 14-catheter sheath as a guide for the guide wire insertion.

Insert the guide wire dorsally into the base in line with the intramedullary canal under image intensification until the tip reaches the head.

Confirm correct rotational alignment.

Antegrade intramedullary screw fixation of an extraarticular transverse fracture of a metacarpal head - Guide wire insertion
Pearl: With the wrist in full flexion, insert the guide wire in a retrograde fashion exiting the metacarpal base under image intensification. Incise the skin at the exit point and advance the wire further.
Antegrade intramedullary screw fixation of an extraarticular transverse fracture of a metacarpal head - Guide wire insertion

Screw insertion

Predrill the entry point and if needed the medullary canal. This creates a track for screw insertion and reduces the risk of deviation during screw insertion.

Insert the selected screw over the guide wire until the head is fully entered into the metacarpal and the fracture is compressed.

Pearl: Hold the distal metacarpal segment once the threads engage the isthmus to prevent malrotation.

Confirm reduction and correct screw placement with an image intensifier.

Antegrade intramedullary screw fixation of an extraarticular transverse fracture of a metacarpal head - Screw insertion

6. Final assessment

Confirm correct rotational alignment by clinical examination.

Image intensification may be used to confirm anatomical reduction and correct placement of implants in two views.

7. Aftercare

Postoperative phases

The aftercare can be divided into four phases of healing:

  • Inflammatory phase (week 1–3)
  • Early repair phase (week 4–6)
  • Late repair and early tissue remodeling phase (week 7–12)
  • Remodeling and reintegration phase (week 13 onwards)

Full details on each phase can be found here.

Postoperative treatment

If there is swelling, the hand is supported with a dorsal splint for a week. This would allow for finger movement and help with pain and edema control. The arm should be actively elevated to help reduce the swelling.

The hand should be splinted in an intrinsic plus (Edinburgh) position:

  • Neutral wrist position or up to 15° extension
  • Metacarpophalangeal (MCP) joint in 90° flexion
  • Proximal interphalangeal (PIP) joint in extension
Dorsal splint to treat a dislocation of the proximal interphalangeal joint

The reason for splinting the MCP joint in flexion is to maintain its collateral ligament at maximal length, avoiding scar contraction.

PIP joint extension in this position also maintains the length of the volar plate.

The metacarpophalangeal joint in flexion maintains the collateral ligament at maximal length and the proximal interphalangeal in extension maintains the length of the volar plate.

After subsided swelling, protect the digit with buddy strapping to a neighboring finger to neutralize lateral forces on the finger.

Buddy strapping avoiding direct skin contact with adjacent fingers as conservative treatment

Functional exercises

To prevent joint stiffness, the patient should be instructed to begin active motion (flexion and extension) immediately after surgery.

Functional exercises for the hand

Follow-up

See the patient after 5 and 10 days of surgery.

Implant removal

Intramedullary screws should not be removed as this may result in cartilage damage.

8. Case

Intraoperative view of a reduced neck fracture of the 5th metacarpal with the guide wire and the cannulated intramedullary screw inserted through the metacarpal head

Intraoperative image showing the guide wire and screw for intramedullary screw fixation of the 5th metacarpal fracture