Website under Maintenance Work

image traffic cones
Due to maintenance work,
our Website www.aofoundation.org with all connected services, like AO Surgery Reference, Event Management, Infonet Databases, Fellowship etc,
will be offline (NOT accessible)
during November 26-27

Executive Editor: Chris Colton

Authors: Renato Fricker, Matej Kastelec, Fiesky Nuñez, Terry Axelrod

Thumb - Proximal phalanx: Articular (head) - bicondylar

back to Hand overview

Glossary

1 Principles top

T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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

T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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.


T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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.


T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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

T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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

T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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.


T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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.


T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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.


T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

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.

5 Fixation top

T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

Insert first lag screw

Remove the drill bit and insert the first lag screw. Carefully tighten the screw to achieve interfragmentary compression.


T-shapred fracture of the proximal phalanx PIP joint – Lag screw fixation enlarge

Insert second lag screw

Insert the second lag screw and tighten it.

v1.0 2008-11-08