Extension Block Pinning 26756

synonyms:  bony mallet fracture, bony mallet finger, distal plangeal fracture, DIP fracture dislocation, intra-articular distal phalanx fracture, CRPP distal phalangeal fracture, CRPP bony mallet fracture

Extension Block Pinning CPT 

 boney mallet finger  Boney Mallet Finger Anatomy
  1. Terminal Extensor tendon: DIP extension is provided by the the conjoined lateral bands which insert into the base of the distal phalanx and are made of the lateral slips of the extrinsic extensor tendon and the lateral bands from the intrinsic interosseous and lumbrical muscles.
  2. Middle Phalangeal Head
  3. FDP tendon
  4. Dorsal base
  5. Volar base
  6. Shaft
  7. Tuft (head)
distal plalanx mallet fracture

Dorsal Base Distal phalanx fracture

  • i.e.bony mallet fracture
  • The forces created by the extensor tendon and FDP tendon may displace the fracture resulting in joint subluxation.

Extension Block Pinning Indications

  • Displaced dorsal base distal phalanx fracture

Extension Block Pinning Technique

  • CPT: 26432(closed treatment of distal extensor tendon insertion, with or without percutaneous pinning)
  • Mini C-arm.
  • Pre-operative antibiotics.
  • Supine postion with hand table.
  • Sterile prep and drape.


CRPP bony mallet
  • DIP joint is hyperflexed reducing the small dorsal fragment into its anatomic position. Consider using the blunt end of a k-wire to hold pressure on the dorsal cortex of the fragment to prevent the terminal extensor tendon from rotating it into extension. (Henry MH in Fractures in Adults 6th ed.)
  • 0.045-in K-wire is placed just proximal to the dorsal fragment preventing its displacement.
Extension Block pinning technique 
  • Large Volar fragment is then reduced to the dorsal fragment anatomically. Consider using the flat surface of a freer elevator placed transversely across the volar base just distal to the distal flexion crease to prevent cantilever bending of the volar fragment. (Henry MH in Fractures in Adults 6th ed.)
  • Ensure articular surface is restored.
  • 0.045-in K-wire is placed longitudinally in the distal phalanx centrally in both the A/P and lateral planes maintaing reduction of the volar fragment.
  • K-wires are bent and cut short.