T-plate fixation

When vertical compression forces, created by axial load, are applied to the finger, comminuted, intraarticular, compression fractures may result. These fractures are very unstable.
Typically, they occur in two configurations:

• as centrally impacted, comminuted fractures, or
• with a T- or Y-type fracture geometry.

It is desirable to obtain stable fixation to allow early motion and to minimize the risk of degenerative joint disease.

For this procedure the following approaches may be used:

• Dorsal approach to the phalangeal metaphysis (after Pratt)
• Dorsal approach to the MCP joint

Compression fractures are not reducible by ligamentotaxis, as the centrally impacted fragments are devoid of soft-tissue attachments.
Direct reduction is therefore necessary.
The key to fixing compression fractures is restoring the joint surface to as close as normal as possible, and supporting the reduction with bone graft and internal fixation.

Using a K-wire, or dental pick, the fragments are disimpacted and pushed towards the head of the metacarpal, which is used as a template to ensure congruity of the articular surface of the phalanx.
If a cartilage step-off greater than 1 mm remains, degenerative joint disease may follow.

Since the metaphyseal cancellous bone is impacted, a void may be created by its disimpaction.
This jeopardizes the fracture in two ways:

• this is a very unstable situation in which the fragments may easily redisplace (collapse)
• the healing process is delayed.

T- and Y-shaped fractures
If the plate is not sufficiently contoured to follow the geometry of the concavity of the base of the phalanx, tightening the screws will result in fracture distraction, creating a gap in the opposite cortex.

By overbending the plate, compression can be exerted on the opposite cortex. This may only be applied in fractures with large fragments, never in small-fragment comminution fractures, as the reduction may be compromised (collapse).

Comminuted fractures
In comminuted fractures it is important to contour the plate to perfectly fit the bone. Neither compression nor distraction forces should occur through screw tightening, as the reduction would be compromised (collapse).

Pitfall
If compression is exerted on the comminuted zone in the sagittal plane by overbending the plate, angulation of the finger will result.

The plate is placed dorsally on the phalanx, as proximally as possible, without interfering with the joint.
Ensure that the plate is centered on the long axis of the diaphysis.

Using a drill guide, carefully drill a first hole for a screw through the transverse part of the plate with a 1.0 mm drill bit.
Repeat for the second hole in the transverse part.

Pitfall
Be sure not to injure the flexor tendons and digital artery and nerve.

Use a depth gauge to determine screw length.

Insert the first screw. Ensure that it engages the far cortex but does not protrude into the fibro-osseous flexor digital channel, where the flexor tendons run. The digital nerve and artery are also at risk of injury.
Insert a second screw into the opposite end of the transverse plate section, in the same fashion, alternately tightening both screws.

Check for perfect adaptation of the plate to the diaphysis and metaphysis. If it is not perfectly adapted, take out the screws and recontour the plate to avoid fracture displacement, or malrotation.

Conflict of tips of the screws in the transverse part of the plate and joint penetration must be avoided.

Use a drill guide and 1.0 mm drill bit to prepare an eccentric hole for the distal plate screw.

Use a depth gauge to determine screw length.

Insert the distal, self-tapping screw and tighten it.
Prepare and insert another, more proximal diaphyseal screw, in the same fashion.

Immobilize the hand in a safe position for at least 3 weeks. This may not be necessary in the case of large fragments when the lag screw fixation is judged at operation to be absolutely stable. In that case, buddy strapping is applied immediately postoperatively.

See patient 5 days after surgery to check the wound, clean and change the dressing. After 10 days, remove the sutures. Check x-rays.

Remove the splint at 3 weeks, and apply buddy strapping.

Then begin with active motion exercises.