Clinical Examples: Phalangeal head exostosis variations

Case 1. 14 year old boy with radial prominence and ulnar deviation of the middle finger proximal interphalangeal joint. Painless, no history of trauma.

Radiographs showing well circumscribed calcification at the  proximal phalanx collateral ligament origin, 10 degrees of lateral angulation.

This was treated with simple excision. Pathology was consistent with mature bone.

Case 2. Mass developing after a lateral dislocation of the proximal  interphalangeal joint of a 34 year old woman.

Radiographs were consistent with either a united collateral ligament avulsion fracture or ossiification of a parosteal hematoma.

This was treated with simple excision and collateral ligament repair to local tissues.

Late result.

Case 3. 21 year old woman with pain developing in a congenitally angulated thumb.

Radiographs show a juxtaarticular ossification with  subchondral cyst formation of the bone interface with the lateral phalangeal head and lateral angulation of the proximal phalanx articular surface.

This was treated with excision of the mass and corrective closing wedge osteotomy of the proximal phalanx.

There was no articular cartilage on the pseudojoint, with  arthritic type reactive changes.

Corrected alignment

Intraoperative fluoroscopy. The mass:

Osteotomy planning: proximal pin parallel to the proximal joint line, distal pin parallel to the distal joint line:

Pins were used as saw blade alignment guides:

Osteotomy closed:

Intraosseous wire passed through pin tracts, interfragmentary pin:

Late result: