Minicondylar compression plate fixation

Fractures of the metaphysis can be transverse, oblique, or comminuted.
Obliquity of the fracture is possible either in the plane visible in the AP view, or in the plane visible in the lateral view. Always confirm the fracture configuration with views in both planes.

Indirect reduction is achieved by traction and digital manipulation. When the fracture is stable, it can be treated nonoperatively.
If the fracture is irreducible, ORIF is indicated.
Other indications for ORIF are open fractures, or soft-tissue lacerations.

For this procedure the following approaches may be used:

• Midaxial approach to the proximal phalanx
• Dorsal approach to the phalangeal metaphysis (after Pratt)

Reduction can be obtained by traction and flexion exerted by the surgeon.
Confirm reduction under image intensification.
Sometimes, these fractures are stable after reduction if the obliquity is minimal. In this case, nonoperative treatment is indicated.

Direct reduction is necessary when the fracture can not be reduced by traction and flexion, or is unstable.
When indirect reduction is not possible, this is usually due to interposition of parts of the extensor apparatus.
Use a pointed reduction forceps for direct reduction.

Retain the pointed reduction forceps for preliminary fixation, or insert a 1.0 mm K-wire.

At this stage, after provisional fixation, 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 the fingers in a degree of flexion, and never in full extension. Malrotation may manifest itself by overlap of the flexed finger over its neighbor. Subtle rotational malalignments can often be judged by tilting 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, 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.

In case of an oblique fracture as illustrated, there are two options:

1) Minicondylar plate
This plate allows axial compression and, because of its lateral placement, the additional insertion of a lag screw across the fracture plane through the plate, improving the quality of fixation.
This is the preferred option.

2) T-Plate (adaption plate)
In this case, the lag screw must be inserted independently of the plate. The plate is added as a second step and acts as a protection plate. This choice calls for additional soft-tissue dissection for the insertion of the lag screw.

If the fracture line is oblique as in this illustration, the same options, but with different implications, apply:

1) Minicondylar plate
Because of the lateral plate placement, an additional lag screw has to be inserted independently of the plate. The plate itself has only a protection function.

2) T-plate (adaption plate)
The dorsal placement of this plate permits insertion of a lag screw through the plate, in this fracture configuration. This is the preferred choice because of the better stability and lesser soft-tissue dissection.

In order to prevent the fracture from displacing when compression is applied, the plate should be attached to the side of the phalanx on which the proximal fracture line forms an acute angle (axilla) with the plate.

If the plate is placed so that the distal fracture line forms an obtuse angle with the plate, the application of axial compression may well cause the fracture to displace.
Move the plate to the opposite side.

In order to determine the position of the first drill hole, it can be very helpful to turn the plate over and use it as a template.

Drill a 1.5 mm transverse hole through the base of the proximal phalanx adjacent to the subchondral bone.

The drill hole needs to be sufficiently dorsal to leave enough space for the plate’s most proximal hole, adjacent to the blade.

Measure the length of the drill hole.
Cut the blade of the plate to the determined length, so that it just fills the drill hole.

Pitfall
Avoid protrusion through the opposite cortex, as friction during movement and eventual ligament injury may result.

Adapt the plate length to fit the length of the proximal phalanx. Avoid sharp edges which may be injurious to the tendons. There should be at least 3 plate holes distal to the fracture available for fixation in the diaphysis. At least two screws need to be inserted into the diaphysis.

Pearl: Cut the blade transversely
If you cut the blade on the flat, it will compress and widen very slightly as it is cut. This makes its maximal width very slightly larger than 1.5 mm. It may not fit in the 1.5 mm hole that you have drilled.
Therefore, cut the blade on edge (to deform it through its narrower dimension) to the correct length. The resultant tip is somewhat arrow-shaped.

Use pliers to contour the plate so that it fits exactly the anatomy of the base of the proximal phalanx.
The plate was designed for condylar fractures and is precontoured to fit around a condyle. It has to be adapted for the less curved shape of the proximal phalanx.

Introduce the blade into the drill hole. Gently push with the thumb until the plate is fully seated.

Before inserting the first (proximal) screw, ensure that the plate is in line with the phalangeal diaphysis in the sagittal plane by rotating it around the axis of the blade.

Insert proximal screw
The proximal screw is inserted next in a neutral position.
The screw should just engage the far cortex.

Note
Be careful to avoid screw protrusion, as ligament injury may result from friction during movement.

Use a 1.1 mm drill bit to prepare the first screw hole at the distal end of the plate.
This hole must be drilled eccentrically to produce axial compression.

Measure for screw length and insert a self-tapping 1.5 mm screw in an eccentric position.
Tightening the screw will axially compress the fracture.

Insert a lag screw through the plate:
Using a 1.5 mm drill guide, drill a gliding hole in the near (cis) cortex through the plate as perpendicularly to the fracture plane as possible. Then drill a 1.1 mm thread hole just through the far (trans) cortex.
Insert the lag screw and tighten it, giving additional stability to the fracture by producing interfragmentary compression.

Insert a further screw into one of the diaphyseal holes in a neutral position, in order to complete the fixation.

Protect the digit with buddy strapping to the adjacent finger, to neutralize lateral forces on the finger.

The patient can begin active motion (flexion and extension) immediately after surgery.

See patient after 5 days 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’s restricting finger movement, tenolysis, or arthrolysis become necessary. In these circumstances, take the opportunity to remove the implants.