1 Principles topenlarge
Fractures of the diaphysis 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 topenlarge
Indirect reduction by traction
Reduction can be obtained by traction and flexion exerted by the
Confirm reduction under image intensification.
These fractures may be stable after reduction, if the obliquity is minimal, especially when the extensor apparatus is intact, as it functions similarly to a tension band. 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.
It is wise to use magnifying loupes in order to be able to recognize undeveloped fracture lines.
Gently use pointed reduction forceps for direct reduction. For better direct vision, irrigate the fracture zone.
Confirm reduction under image intensification.
Use a pointed reduction forceps to hold the preliminary reduction, or insert a 1.0 mm K-wire.
3 Check alignment topenlarge
At this stage, after provisional fixation, it is advisable to check the
alignment and rotational correction by moving the finger through a range of
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.
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.
Alternatively, the surgeon can exert pressure against the muscle bellies of the proximal forearm to cause passive flexion of the fingers.
4 Preparation topenlarge
Fracture plane & plate position
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.
If the obliquity is visible in the AP view, a lateral plate should be applied so that a lag screw can be inserted through the plate perpendicular to the fracture line.
The plate should be applied either dorsally or laterally on the phalanx, depending on the plane of the obliquity. If the obliquity is visible in the lateral view, the plate should be applied dorsally for the same reason.
We shall now show an oblique fracture with a dorsally applied plate.
Bending and contouring the plate
The dorsal surface of the proximal phalanx is gently convex. If a straight
plate is not adequately contoured to follow this convexity, tightening of the
distal screw will open the fracture on its palmar aspect.
To overcome this, the plate is slightly overcontoured so that when the distal load screw is tightened, compression is generated evenly over the whole fracture surface.
Select a plate with at least 5 holes, and center it over the fracture.
Ensure that the plate is centered on the diaphysis in the transverse section.
If the plate is not properly centered in the transverse section, the screws may fail to cross the medullary canal and will not have sufficient purchase. Secondary fractures may result.
Position the plate so that the hole for the screw in the fragment that will
form an acute angle (axilla) between the fracture surface and the plate, is as
close to the fracture line as possible.
If a stable axilla is not created, and the load is applied in the opposite direction, shearing forces will displace the fracture when the eccentric screw is tightened.
Keep in mind the planned position of the lag screw.
5 Fixation topenlarge
Using a drill guide, carefully drill a first neutral hole with a 1.1 mm drill bit. Ensure that the drill bit does not protrude into the fibro-osseous flexor digital tunnel, where the flexor tendons are. The digital nerve and artery are also at risk of injury.
Use a depth gauge to determine screw length. Failure to take accurate measurement of the required screw length risks failure properly to engage the far cortex, weakens the fixation and carries the risk of implant failure.
Pitfall: avoiding excessive screw length
Remember that the palmar cortex of the phalanx is slightly concave, where it forms the bony roof of the flexor tunnel. For this reason, lateral x-ray images can deceive the surgeon in terms of appropriate screw length, as illustrated here. The screw of the correct length will appear, on a lateral x-ray, to be about one thread pitch short of the palmar cortical image.
Insert the first screw in a neutral position. Ensure that it engages the far cortex but does not protrude into the fibro-osseous tunnel, where the flexor tendons run. The digital nerve and artery are also at risk of injury.
Insert second screw
Insert a second screw in a neutral position on the same side of the fracture, in a similar fashion to above.
Insert third screw eccentrically
Drill eccentrically for the third screw on the other side of the fracture,
leaving empty the plate hole for the planned lag screw. Measure for screw
length, and eccentrically insert a screw.
Tightening this eccentric screw will compress the fracture axially.
Lag screw insertion
Using a 1.5 mm drill guide, drill a gliding hole through the plate, as
perpendicularly to the fracture line as possible. Then drill a 1.1 mm threaded
hole down to the far cortex.
Insert the lag screw and tighten it, giving additional stability to the fracture by applying interfragmentary compression.
Insert an additional neutral diaphyseal screw to complete the fixation.
Order of screw insertion
The screws are inserted in an order depending on the direction of the
oblique fracture line:
If the fracture runs from dorsal/proximal to palmar/distal, the proximal screws are inserted first, and the distal load screw second, followed by the lag screw, and then a final neutral screw.
If the fracture line runs from dorsal/distal to palmar/proximal, the distal screws are inserted first, and the proximal load screw second, followed by the lag screw, and then a final neutral screw.