Extensor Tendon Injuries

Mallet finger

  • An avulsion of the extensor tendon from the distal phalynx resulting in inability to actively extend the DIPJ (flexion deformity)

Aetiology

  • Caused by an object hitting the tip of the finger or thumb; the force of the blow tears the extensor tendon

Clinical presention

  • Tenderness/bruising
  • No resisted finger extension on examination
notion image

Management

  • Mallet splint for 6 weeks (24/7) if joint is congruent
  • If joint is not congruent (large displaced avulsion fracture) reduce the joint and fixate with K wires or screws
    • Non-congruent joints will be predisposed to secondary OA
  • Dermatotenodesis in chronic cases (3 months +)

Extensor pollicus longus rupture

Aetiology

  • Can occur with RA: autoimmune attack on synovium → tendon degeneration → rupture
  • Can also occur secondary to Colles fracture

Clinical presentation

  • Substantial loss of function - can't extend thumb at MCP/IPJ

Management

  • If caught during preceeding synovitis from RA, a synovectomy can help prevent rupture
  • Once rupture has occured, a tendon transfer is required (EIP)