Executive Editor: Chris Colton

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

Middle phalanx - PIP joint - central impaction fracture

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Glossary

1 Principles top

Typically, hyperextension of the proximal interphalangeal (PIP) joint causes an avulsion fracture of the volar ... enlarge

Mechanism of the injury

Digital hyperextension injuries are commonly caused by sporting accidents.
Typically, hyperextension of the proximal interphalangeal (PIP) joint causes an avulsion fracture of the volar plate. If there is significant axial load on the middle phalanx, the compression forces across the PIP joint lead to an impaction fracture in association with a palmar avulsion fracture.


In the presence of palmar instability of the PIP joint, muscle forces (flexor digitorum superficialis and the central ... enlarge

Deforming forces

In the presence of palmar instability of the PIP joint, muscle forces (flexor digitorum superficialis and the central extensor slip) lead to palmar tilting and dorsal subluxation, depending on the degree of the impaction.


AP and true lateral x-rays are necessary for diagnosis. Be careful to avoid overlap of other fingers in the x-rays. enlarge

Recognizing subluxation

Diagnosis is based on

  1. the clinical history and mechanism of injury
  2. the clinical examination of the patient
  3. the x-rays

AP and true lateral x-rays are necessary for diagnosis. Be careful to avoid overlap of other fingers in the x-rays.
An AP view will help to detect impaction fractures.
Often, a subluxation is not easily recognized in the lateral view. Look for the characteristic “V” sign of diverging joint surfaces, which indicates this injury.


Impaction is possible both in the sagittal and the coronal planes. Check both true AP and lateral views. enlarge

Check for impaction injuries

Impaction is possible both in the sagittal and the coronal planes. Check both true AP and lateral views.


Malalignment in the coronal plane may be a sign of impaction. enlarge

Malalignment in the coronal plane may be a sign of impaction.

2 Reduction top

Use a K-wire, a dental pick, or a small curette to push the depressed fragments towards the head of the proximal ... enlarge

Reduce the depressed articular fragments

Use a K-wire, a dental pick, or a small curette to push the depressed fragments towards the head of the proximal phalanx, which should be used as a template to ensure congruity of the articular surface of the middle phalanx to reduce the risk of later degenerative joint disease.


Since the subchondral cancellous bone is impacted, a void may remain following reduction of these articular fragments. enlarge

Since the subchondral cancellous bone is impacted, a void may remain following reduction of these articular fragments.

This jeopardizes fracture healing:

  • This is a very unstable situation in which the fragments may collapse
  • The healing process is very slow

Therefore bone grafting is recommended.

3 Bone graft top

Harvest the graft material from the distal radius. A good and safe place is proximal and slightly radial to Lister’s tubercle. enlarge

Harvest site

Harvest the graft material from the distal radius. A good and safe place is proximal and slightly radial to Lister’s tubercle.


Make a 2 cm longitudinal incision proximal to Lister’s tubercle. Retract the tendons of the second compartment radially, ... enlarge

Harvesting

Make a 2 cm longitudinal incision proximal to Lister’s tubercle. Retract the tendons of the second compartment radially, and the extensor pollicis longus (EPL) in an ulnar direction.


Use a chisel to cut three sides of a small square. Lift the dorsal radial cortex as a flap. After harvesting cancellous ... enlarge

Use a chisel to cut three sides of a small square. Lift the dorsal radial cortex as a flap. After harvesting cancellous bone, replace the “lid”, and suture the periosteum and the skin incision.


Use a pusher instrument to impact the bone graft and fill the whole fracture cavity. enlarge

Use a pusher instrument to impact the bone graft and fill the whole fracture cavity.
Confirm reduction using image intensification.

4 Fixation top

Maintaining the reduction with slight pressure from a drill guide, drill a threaded hole using the corresponding drill. enlarge

Drilling

Maintaining the reduction with slight pressure from a drill guide, drill a threaded hole using the corresponding drill.


If too long a screw is chosen, the protruding end may damage the extensor tendon. enlarge

Pitfall: Too long a screw irritates extensor tendon

If too long a screw is chosen, the protruding end may damage the extensor tendon.


Insert the screw and carefully tighten it just enough to hold the reduction. The screw should just penetrate the opposite ... enlarge

Screw insertion

Insert the screw and carefully tighten it just enough to hold the reduction. The screw should just penetrate the opposite cortex.

Check joint congruity using image intensification. Reduction must be anatomical.


Be careful not to overtighten the screw as this may result in comminution of the palmar marginal fragment. enlarge

Pitfalls:

Using a lag screw
Using a lag screw would lead to collapse of the bone graft and redisplacement the articular fragments.

Overtightening the screw
Be careful not to overtighten the screw as this may result in comminution of the palmar marginal fragment.

v1.0 2008-11-08