1 Principles top
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Indications
Bicondylar fractures of the head of the proximal phalanx may be T-shaped,
with a long or a short T.
Another pattern of fracture is a combination of a long oblique fracture
separating one condyle, together with a short oblique, or transverse, fracture
separating the other condyle (sometimes called “lambda” fractures, because of
their resemblance to the Greek letter “λ“).
Lag screw fixation is indicated both for the short T-shaped and the lambda
fractures.
Typically these fractures are the results of sports injuries, due to axial load
combined with lateral angulation of the finger.
Condylar fractures tend to be very unstable and should be treated operatively.
If nonoperative treatment is attempted, secondary displacement is likely,
leading to angulation of the finger.
Caveat
These fractures are rare, but difficult to treat. There is an
increased risk of joint stiffness resulting from these fractures.
It is wise to use magnifying loupes in these procedures. Gentle and precise handling throughout the procedure is mandatory.
2 Reduction top
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Anatomical reduction mandatory
Articular fractures must be reduced anatomically. Otherwise, the articular
cartilage may be damaged, leading to painful degenerative joint disease and
digital deformity.
This illustration shows how even slight unicondylar depression may lead to
angulation of the finger.
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Visualization of the fracture
In order to gain a better view of the fracture, use a syringe to irrigate
out blood clot with a jet of Ringer lactate.
Gently explore the fracture site to assess its geometry, using a dental pick.
The pick can also be used carefully to reduce small fragments. Take great care
to avoid comminution of any fragment.
It is important to maintain the vascularity of tiny fragments attached to the
collateral ligament, in order to avoid osteonecrosis.
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Indirect reduction
Reduction starts with traction in order to restore length.
Lateral pressure, exerted by the surgeon’s thumb and index finger, will then
reduce the fracture.
Confirm reduction using image intensification.
3 Preparation top
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Most of the fracture line on the lateral aspect of the head is covered by the collateral ligament.
Flexing the PIP joint will draw back the collateral ligament, which can be further retracted with a hook to expose the intraarticular lateral aspects of the condyles.
4 Drilling top
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Location of the drill holes
On the lateral intraarticular aspects of the condyles, there is a small ridge on each side. These are uniquely suited for screw placement, as the screws can be buried deep to the edge of the cartilage without violating the joint surface and avoiding causing irritation.
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Drilling
Hold the condyle in the reduced position with a dental pick. Some surgeons
use pressure from the drill guide to hold the reduction during drilling.
Drill a gliding hole as perpendicularly to the fracture plane as possible at
the site of this ridge, using a 1.0 mm drill bit for a 1.0 mm screw.
Use a 0.8 mm drill bit to drill a thread hole in the opposite fragment, just
through the far (trans) cortex.
With very small fragments, it may be advisable to drill with manual rotation of
the bit, rather than a powered driver.
Pearl: use drill bit for temporary fixation
Leave the drill bit in the drill hole to preliminarily hold the fragment in
place.
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Planning the second screw track
Be careful to drill the screw track in the other condyle at a different level from the track in the opposite condyle. This way the screws will not conflict with each other.
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Drill the second condyle
In the second condyle, drill a gliding hole as perpendicularly to the
fracture plane as possible, using a 1.0 mm drill bit for a 1.0 mm screw.
Use a 0.8 mm drill bit to drill a threaded hole in the opposite fragment, up to
the far (trans) cortex.
