.

Fig : -

Extensor carpi radialis longus (ECRL), Extensor carpi radialis brevis (ECRB), Extensor carpi ulnaris (ECU), Extensor digitorum communis (EDC), Extensor digiti minimi (EDM), Extensor indicis proprius (EIP), Abductor polliis longus (APL), Extensor pollicis brevis (EPB) andExtensor pollicis longus (EPL). Fig :

Fig :- showing the central slip and lateral bands Fig :

Mallet Finger (baseball finger, drop finger, cricket finger ). Mallet finger of tendon origin Mallet finger of bony origin Mallet finger : flexion deformity of terminal phalanx due to avulsion or rupture of extensor tendon Mallet : hammer like

Mallet Finger 1 Presentation –DIP Flexion +/- edema. Imaging –AP, lateral, oblique

Mallet Finger 1

Mallet finger: Clinical presentation

. Fig : -

Mallet finger deformity due to a closed rupture of the extensor tendon with an associated avulsion fracture of the terminal phalanx

Tendon origin Due to loss of extensor tendon continuity at the distal finger joint Mechanism of injury : The end of the finger is forcibly flexed, when extensor tendon is taut, e.g catching a ball, striking an object with extended finger

Extensor tendon rupture Fig : -

Fig : mallet deformity of the right middle finger along with the normal left finger shown for comparison.

Cont.. Baseball finger (dropped finger, mallet finger). Lateral view

Four types of mallet finger injuries Type I: Closed with or without avulsion fracture Type II: Laceration at or proximal to the DIP joint with loss of tendon continuity Type III: Deep abrasion with loss of skin, subcutaneous cover and tendon substance Type IV: (A) Trans-epiphyseal plate fracture (B) Hyperextension injury with fracture of the articular surface and (C) Hyperextension injury with fracture of the articular surface and with early or late palmar subluxation of the distal phalanx.

Fig :- mallet finger injury at the DIP joint

Treatment For type I injuries : - continuous splinting of the DIP joint in extension for six weeks, followed by two weeks of night splinting. - K – wire fixation of the DIP joint in extension, for six weeks followed by two weeks of night splinting.

Fig :showing the use of a splint in treating closed mallet injury

Type II injuries may be repaired with a simple figure-of-eight suture through the tendon alone. DIP joint is splinted in extension for 6 weeks, followed by 2 weeks of night splinting.

Cont.. Type III injuries with loss of tendon substance require : immediate soft tissue coverage and primary grafting or late reconstruction using a free tendon graft.

Cont.. Type IV-A : - closed reduction followed by splinting for 3-4 weeks. Type IV-B with no palmar subluxation:- good results with 6 weeks splinting and 2 weeks night splinting. Type IV-C with palmar subluxation of the distal phalanx : - open reduction and internal fixation using K - wire. splint for 6 weeks, after which the wire is removed and motion started.

Fig : - external fixator in position..

Posture When relaxed, the hand lies in a characteristic posture with the thumb-tip held slightly flexed and fingers held in a cascade. Any change in the resting posture can suggest tendon or even nerve damage Fig : -

Fig : - Examination of the extensor tendons showing normal function of the extensor communis (left) and extensor proprius (right) tendons

Flexion of the fingers demonstrates loss of active movement at the tip of the ring finger (due to a closed flexor tendon (FDP) rupture )

Mallet Finger Thumb Splint