Extensor tendon injuries

Understanding extensor tendons

Extensor tendons are the structures that allow you to straighten your fingers and thumb. These fibrous cords link the muscles in your forearm and hand to the skeletal framework of your digits.

The anatomy becomes more intricate at the finger base, where the main forearm tendon merges with smaller tendons from the hand's intrinsic muscles. Together, they create a complex tendon network across the back of each finger - a central portion controls straightening at your middle knuckle, while side components reconnect further along to extend your fingertip joint.

Sitting directly beneath the skin's surface, these tendons are vulnerable to lacerations across the back of your hand, wrist, or fingers. Injuries over the knuckles pose particular risk. Beyond cuts, closed trauma like jamming injuries can rupture these tendons, typically affecting either the fingertip (creating a "mallet" deformity) or the middle knuckle (boutonnière injury pattern).

    • Laceration across the back surface of your wrist, hand, or digit

    • Unable to fully extend the affected finger or thumb

    • The digit droops or hangs downward

    • Pain when attempting to straighten the finger or thumb

    I'll examine the tendons individually to assess the injury severity and determine appropriate treatment. X-rays may be necessary if glass was involved or if there's concern about joint damage. Ultrasound or MRI scanning occasionally provides additional diagnostic clarity.

  • Surgical repair

    Most complete lacerations require surgical intervention, though partial injuries sometimes heal successfully with splinting or controlled movement programs.

    The procedure can be performed using local anaesthesia, general anaesthesia, or a nerve block. I'll extend the wound to locate both tendon ends and suture them together. Following repair, your hand receives protective splinting to shield the repair site during initial healing.

    Hand therapy rehabilitation

    Your hand therapist typically replaces the surgical splint with a custom lightweight brace within several days and begins a carefully designed exercise protocol. This rehabilitation phase carries equal importance to the surgery itself - strict compliance with your therapist's directions is essential.

    The program maintains gentle tendon mobility to prevent restrictive adhesions while protecting against repair rupture.

    Splinting duration ranges from three to eight weeks depending on injury characteristics. Gradual activity resumption follows, though complete tendon strength restoration takes approximately three months. Functional improvements may continue developing for up to half a year.

    Closed tendon ruptures (without skin wounds) may respond to splinting protocols rather than requiring surgery.

  • Clean extensor tendon lacerations generally heal well with functional restoration, though achieving absolutely full motion isn't guaranteed. More severe injuries involving tissue crushing, skin loss, or bone and joint trauma may yield less optimal results.

    Repair rupture

    This complication most often occurs early during the vulnerable healing phase. You might experience a popping sensation or simply notice altered finger movement. Immediate contact with me or your therapist is critical if you suspect repair failure - prompt intervention is time-sensitive.

    Adhesion formation

    The tendon may develop restrictive scar attachments to adjacent tissues. Additional therapy sessions can help address this. Selected cases benefit from surgical adhesion release (tenolysis), though complete motion recovery remains uncertain even after this procedure.