Each Wednesday, we feature our Splint in the Spotlight. With these articles, we offer you inspiration and
ideas for your future splinting projects and for the wide variety of pathologies you encounter with your clients.
Today, we focus on the “Stack” or “Mallet Finger” Orthosis.
A mallet finger develops when there has been disruption of the terminal slip extensor tendon to the digital phalanx (zone I), causing an inability to actively extend the distal interphalangeal joint (DIP).
The mechanism of injury can be sudden forceful flexion of the extended fingertip or blunt trauma to the dorsum of the finger. The injury can even result in a variable-sized bone avulsion from the distal phalanx or fracture through an open epiphysis.
How are mallet finger injuries classified (Doyle’s Classification of Mallet Finger Injuries)?
- Type 1: closed rupture of tendon insertion
- Type 2: Open injury with tendon laceration
- Type 3: Open injury with deep abrasion with loss of skin, subcutaneous tissue and tendon substance
- Type 4A: trans-epiphyseal plate fracture in children
- Type 4B: avulsion fracture of the distal phalanx involving 20-30% of articular surface
- Type 4C: fracture >50% with palmar subluxation of the distal phalanx