Mallet Finger

Overview

what it is and why it matters

Palmar dissection of the hand and wrist showing the eight carpal bones, flexor tendons, and median and ulnar nerves. — **Hand and wrist anatomy.** Eight small carpal bones form the wrist and connect the forearm to the five metacarpals of the palm. Finger tendons and the median and ulnar nerves pass through narrow tunnels in the wrist on their way into the hand.

Mallet finger is a rupture or avulsion of the terminal extensor tendon at its insertion into the dorsal base of the distal phalanx. The DIP joint drops into flexion and cannot be actively extended. It typically occurs when a ball or object strikes the tip of an extended finger, suddenly forcing the DIP into flexion — common in basketball, baseball, and football players.

A bony mallet involves an avulsion fracture of the dorsal DIP joint; a soft-tissue mallet is a pure tendon rupture.

Diagnosis

exam first, imaging second

Diagnosis is clinical: a drooping DIP joint with inability to actively extend the tip. X-rays are essential to determine whether there is a bony fragment and, if so, whether it involves more than one-third of the articular surface (which may influence treatment).

Treatment Path

how care progresses at OSI

DIP extension splinting

The cornerstone of treatment: continuous DIP extension splinting for 6–8 weeks allows the tendon or avulsion fracture to heal. The DIP must not be allowed to flex during the splinting period — even momentarily. Stack splints or alumifoam splints work well.

Surgical Options at OSI

if non-operative care isn't enough

Surgery is rarely required. Indications include a large bony fragment causing DIP subluxation (>30% articular involvement with volar subluxation) or failure of conservative treatment.

Overview

Diagnosis

Treatment Path

DIP extension splinting

Surgical Options at OSI

Providers Who Treat Mallet Finger

Michael S. Vrana, M.D.

David B. Templin, M.D.

Trent Twitero, M.D.

Further Reading

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