Executive Editor: Chris Colton

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

Thumb - Proximal phalanx: Base and shaft - pilon fractures

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Glossary

1 Principles top

Articular congruity should be restored anatomically. In cases of comminuted impacted fractures (“pilon”), bone graft from ... enlarge

Introduction

Intraarticular fractures of the proximal phalanx of the thumb must be treated radically to avoid

  1. loss of motion
  2. post-traumatic arthrosis.

Articular congruity should be restored anatomically. In cases of comminuted impacted fractures (“pilon”), bone graft from the distal radius is needed to fill the metaphyseal defect.


It is difficult to assess the extent of articular comminution from plain radiographs. A CT scan is advisable. enlarge

It is difficult to assess the extent of articular comminution from plain radiographs. A CT scan is advisable.


Be careful not to detach the insertion of the extensor pollicis brevis (EPB) into one of the basal fragments. enlarge

Choice of approach

In the case of extension of the fracture into the diaphysis, the dorsal approach to the MP joint is modified so that the distal incision extends as far as the interphalangeal (IP) joint. The IP joint itself will not be opened.
Be careful not to detach the insertion of the extensor pollicis brevis (EPB) into one of the basal fragments.

2 Reduction top

With a periosteal elevator, reduce the articular fragments, ... enlarge

Restoration of the articular surface

With a periosteal elevator, reduce the articular fragments, ...


... using the head of the first metacarpal as a template. enlarge

... using the head of the first metacarpal as a template.


Use a pointed reduction forceps to reduce and hold the diaphyseal fragments. enlarge

Reduction of diaphyseal fragments

Use a pointed reduction forceps to reduce and hold the diaphyseal fragments.


During the diaphyseal reduction, check under direct vision that no displacement of articular fragments occurs. enlarge

During the diaphyseal reduction, check under direct vision that no displacement of articular fragments occurs.


In case the fragments are too small for screw fixation, carefully insert a K-wire to fix the articular fragments. enlarge

Fixation of articular fragments

In case the fragments are too small for screw fixation, carefully insert a K-wire to fix the articular fragments.

3 Lag screw fixation top

A first lag screw will be inserted into the middle of the shaft. enlarge

First lag screw in the middle of the shaft

A first lag screw will be inserted into the middle of the shaft.
Drill the gliding hole in the near cortex. Ensure and hold a perfect fracture reduction and then insert a drill guide. Drill the thread hole in the far (trans) cortex through the drill guide.
This method ensures that the threaded hole is perfectly in line with the gliding hole.
Countersink the near cortex as necessary.
Measure for correct screw length.
Insert the lag screw and tighten it.


Repeat the above procedure for a second lag screw to be inserted into the distal part of the diaphysis. enlarge

Second lag screw

Repeat the above procedure for a second lag screw to be inserted into the distal part of the diaphysis.

4 Bone graft top

After diaphyseal fixation, the metaphyseal void must be filled with bone graft to support the reduced articular fragments, and to prevent secondary displacement.


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

Harvest site

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


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

Harvesting

Make a 2 cm long incision proximal to Lister’s tubercle. Retract the tendons of the second compartment radially, and the EPL in an ulnar direction.


Use a chisel to cut three sides of a square. Hinge up the dorsal cortical flap. After harvesting cancellous bone, ... enlarge

Use a chisel to cut three sides of a square. Hinge up the dorsal cortical flap. After harvesting cancellous bone, replace the “lid” and suture the periosteum and the skin incision.


The bone graft is now inserted through a window of the metaphyseal cortex above the articular surface. enlarge

The bone graft is now inserted through a window of the metaphyseal cortex above the articular surface.

5 Plate fixation top

Angularly stable plates are the preferred implants to use for protection. enlarge

Angularly stable plates are the preferred implants to use for protection. This kind of plate protects the reduced articular fragments and improves the stability of the fixation. Thereby they enable immediate postoperative mobilization.

Apply the plate to the bone and insert the screws according to the fracture pattern.

Test the stability of the fixation intraoperatively.


Completed ostesynthesis enlarge

Completed ostesynthesis

6 Closure top

Suture the articular capsule proximally with nonabsorbable sutures. Distally cover the plate with periosteum, also with ... enlarge

Suture the articular capsule proximally with nonabsorbable sutures. Distally cover the plate with periosteum, also with nonabsorbable sutures. This will protect the tendons from irritation as they glide over the plate.

v1.0 2008-11-08