Lag-screw fixation with a neutralization plate

In short oblique fractures, only one lag screw can be inserted. This is insufficient to produce enough stability, and the lag screw must be protected by a plate.

In oblique shaft fractures, straight plates may be used for neutralization.

Obliquity of the fracture is possible either in the plane visible in the AP view or the lateral view. Always confirm the fracture configuration with views in both planes.

In this procedure, an oblique fracture visible in the lateral view is shown with lag-screw fixation protected with a lateral plate.

For neutralization or neutralization plating, several plate types may be used:

• Conventional straight locking compression plate (LCP); dorsal or lateral
• T-plate (adaption plate); dorsal
• Strut plate; dorsal
• Condylar plate; lateral or dorsal

The plates may come with or without variable-angle (VA) locking head screws. If an anatomical plate is not available, a conventional minicondylar plate may be used.

The plate selection depends on the fracture pattern and should allow at least two screws in the proximal and distal main fragments.

In this procedure, the application of a lateral LCP straight plate is shown.

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

For this procedure, the following approach is normally used for application of a lateral plate:

• Midaxial (lateral) approach to the proximal phalanx

Application of a dorsal plate may require a dorsal approach:

• Dorsal approach to the proximal phalanx (after Pratt)

Reduction can be achieved manually by traction and flexion.

Confirm reduction clinically and with an image intensifier. If there is shortening of the finger, then there is often malrotation of the fracture.

If the fracture appears stable after reduction, nonoperative treatment can be considered. Confirming reduction with an image intensifier is then essential.

Hold the reduction with reduction forceps designed for a percutaneous technique. Impingement of soft tissues should be avoided.

Direct reduction is necessary when the fracture cannot be reduced by traction and flexion or is unstable because of surrounding soft-tissue lesions.

When indirect reduction is not possible, this is usually due to interposing parts of the extensor apparatus.

Use pointed reduction forceps for direct reduction.

Insert a K-wire for provisional fixation.

At this stage, it is advisable to check the alignment and rotational correction by moving the finger through a range of motion.

Rotational alignment can only be judged with flexed metacarpophalangeal (MCP) joints. The fingertips should all point to the scaphoid.

Malrotation may manifest by an overlap of the flexed finger over its neighbor. Subtle rotational malalignments can often be judged by a tilt of the leading edge of the fingernail when the fingers are viewed end-on.

If the patient is conscious and the regional anesthesia still allows active movement, the patient can be asked to extend and flex the finger.

Any malrotation is corrected by direct manipulation and later fixed.

Under general anesthesia, the tenodesis effect is used, with the surgeon fully flexing the wrist to produce extension of the fingers and fully extending the wrist to cause flexion of the fingers.

Alternatively, the surgeon can exert pressure against the muscle bellies of the proximal forearm to cause passive flexion of the fingers.

Confirm fracture fixation and stability with an image intensifier.

The lag screw should be inserted centered on and as perpendicularly to the fracture plane as possible and from the dorsal surface. The direction of the obliquity of the fracture plane dictates the exact position of the lag screw.

• Cortical lag-screw insertion

The exact size of the diameter of the screws used will be determined by the fragment size and the fracture configuration.

The various gliding and thread hole drill sizes for different screws are illustrated here.

Apply the neutralization plate depending on the fracture plane and the lag-screw position, either dorsally or laterally.

Insert at least two screws proximally and distally to the fracture in neutral mode.

• Locking head screw insertion
• Screw insertion in neutral mode

Cover the plate with periosteum to avoid adhesion between the tendon and the implant leading to limited finger movement.

Confirm fracture reduction and stability and implant position with an image intensifier.

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.

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
• MCP joint in 90° flexion
• PIP joint in extension

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.

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

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

See the patient after 5 and 10 days of surgery.

The implants may need to be removed in cases of soft-tissue irritation.

In case of joint stiffness or tendon adhesion restricting finger movement, arthrolysis or tenolysis may become necessary. In these circumstances, the implants can be removed at the same time.