Lacerations to the hand are common injuries that present to emergency departments, both in academic Level 1 trauma centers as well as community and rural settings. Lacerations across the dorsal surface of the hand and fingers often injure the extensor tendons of the fingers, leading to difficulty or inability to extend the joints of the finger.

The repair of these tendons is essential to preserving function of the hand and can be performed by a hand surgeon, but it is a relatively simple procedure, and in a resource-limited setting, can be performed by an emergency physician.

Anatomy of Extensor Tendons

For a brief review of the anatomy and physiology of the extensor tendons, the tendons from muscles of the forearm meet the tendons of the hand in a sheet at the base of each finger (near the knuckle). The extensor digitorus communis (EDC) muscle of the forearm supplies tendons that work to extend the index, middle, ring, and small fingers. The index finger has two tendons (EDC and extensor indices proprius). The extensor digiti minimi muscle (EDM), in addition to the EDC, works in conjunction to extend the fifth digit. The extensor pollicis brevis and longus muscles supply the tendons for the thumb. The sheet of tendinous material gives off a central band that extends the middle joint of the finger, and two separate lateral bands that converge together past the joint and function to extend the distal interphalangeal (DIP) joint. Unlike flexor tendons, extensors usually do not retract significantly because of connections called juncturae tendinae.

Diagnosis and Repair

To diagnose an extensor tendon injury, the patient will have pain with, or an inability to extend, one of the joints of the finger or finger drooping. Traumatic etiology of extensor tendon injury involves penetrating or blunt trauma to or with extension to the dorsal surface of the wrist, hand, or finger.

Once diagnosed, repair can be attempted. To prepare for the procedure, use a blood pressure cuff around the forearm and inflate it to 50 mmHg above systolic pressure to control bleeding. You can achieve anesthesia with digital ring block, local anesthetic, or systemic analgesia or moderate sedation, as needed. Liberally irrigate site of injury with 500 mL to 1 L of normal saline and apply sterile drapes around site of procedure.

– FIGURE 1A (LEFT): Modified Kessler stitch

– FIGURE 1B (RIGHT): Modified Bunnell stitch