Mallet Finger

Pathophysiology

Normally, the tendons of the finger flexors glide back and forth under a restraining pulley.[3, 4, 5] Thickening of the flexor tendon sheath restricts the normal gliding mechanism. A nodule may develop on the tendon, causing the tendon to get stuck at the proximal edge of the A1 pulley when the patient is attempting to extend the digit, thereby causing difficulty. When more forceful attempts are made to extend the digit, by using increased force from the finger extensors or by applying an external force (for example, by exerting force on the finger with the other hand), the digit classically snaps open with significant pain at the distal palm and into the proximal aspect of the affected digit. Less commonly, the nodule is restricted distal to the A1 pulley, resulting in difficulty flexing the digit (see image below).

An inflamed nodule can restrict the tendon from passing smoothly beneath the A-1 pulley. If the nodule is distal to the A-1 pulley (as shown in this sketch), then the digit may get stuck in an extended position. Conversely, if the nodule is proximal to the A-1 pulley, then the patient's digit is more likely to become stuck in the flexed position.

Epidemiology

Frequency

United States

Trigger finger is a relatively common condition.

Mortality/Morbidity

* Morbidity: Trigger digits can be a significant source of pain. In addition, the difficulty in achieving a normal range of motion at the digit can make functional tasks (eg, grasping objects, typing) problematic.

* Mortality: No mortality is known to be associated with this condition.

Race

No racial predisposition is known to be associated with trigger finger.

Sex

This condition has a higher incidence in women (75%) than in men.

Age

Trigger digits are most commonly seen in adults, with the average age range for its occurrence being 52-62 years.

Physical

At the level of the distal palmar crease, a tender nodule can be palpated, usually overlying the...