1 Principles top
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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.
2 Reduction top
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Indirect reduction by traction
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.
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Direct reduction
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.
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Preliminary fixation
Retain the pointed reduction forceps for preliminary fixation, or insert a 1.0 mm K-wire.
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Identifying malrotation
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.
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Using the tenodesis effect when under anesthesia
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.
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Passive flexion
Alternatively, the surgeon can exert pressure against the muscle bellies of the proximal forearm to cause passive flexion of the fingers.
3 Plate selection top
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Fracture oblique in AP view
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.
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Fracture oblique in the lateral view
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.
4 Drilling top
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Planning plate position
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.
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Pitfall: Fracture displacement
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.
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Determine location of drill hole
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.
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Drilling
Drill a 1.5 mm transverse hole through the base of the proximal phalanx adjacent to the subchondral bone.
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The drill hole needs to be sufficiently dorsal to leave enough space for the plate’s most proximal hole, adjacent to the blade.
5 Plate preparation top
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Prepare 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.
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Trim the plate
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.
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Contouring of the plate
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.
6 Fixation top
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Plate application
Introduce the blade into the drill hole. Gently push with the thumb until the plate is fully seated.
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Align the plate with the diaphysis
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.
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Drill eccentric distal hole
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.
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Fracture 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.
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Lag screw
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.
Finalize fixation
Insert a further screw into one of the diaphyseal holes in a neutral position, in order to complete the fixation.
