A mallet finger is where the end of a finger is bent (flexed) towards the palm and cannot straighten = loss of extensor mechanism at the distal interphalangeal (DIP) joint, also commonly known as “baseball finger” or “drop finger” (Alla, Deal and Dempsey, 2014).
Mallet finger is an injury of the extensor tendon, so the finger loses the ability to straighten completely, which is why it is hold in a bent/flexed position.
The usual cause is an injury to the end of the finger. It is a common injury when trying to catch a ball and the catch is missed slightly then the ball hits the straight finger. This may force the end of the finger to bend (flex) further than normal and tear the tendon. Without the use of this tendon, the finger stays bent (flexed).
There are several different options how to treat a Mallet finger, mainly talking about splints and surgical techniques, however, no gold standard has been described so far. Most surgeons represent the opinion, that conservative treatment with splints produces satisfactory results for tendon avulsions without fractures or minimally displaced fractures (Alla, Deal and Dempsey, 2014). Full time splinting for 6 weeks, followed by 2-6 weeks of splinting at night is recommended.
Alla S.R., Deal N.D. and Dempsey I.J., 2014, Current concepts: mallet finger, Hand: official journal of the American Association for Hand Surgery, 9(2), pp: 138-144