Flexor tendon injuries involve damage to the tendons that allow finger flexion, impacting hand function.
The flexor tendons run from muscles in the forearm, through the wrist and palm, to the fingers, and are responsible for bending the fingers to grip. Because they lie just beneath the skin on the palm side of the hand and fingers, they are vulnerable to injury from cuts in this area.
A flexor tendon injury is usually a laceration that partially or completely divides the tendon, resulting in reduced or absent ability to bend the finger at one or both joints. Because a divided tendon does not reliably heal or reconnect on its own, timely surgical repair is important for the best outcome.
The most common cause is a laceration, a cut from glass, a knife, machinery or a sharp edge, since the flexor tendons run close to the skin surface on the palm side of the fingers and hand. Kitchen accidents, workshop injuries and falls onto glass are frequent scenarios.
Less commonly, a flexor tendon can rupture without any visible cut, from a sudden forceful bending of an actively straightening finger, an injury sometimes seen in contact sports when a finger catches on clothing or equipment.
The key signs of a flexor tendon injury are:
Any laceration on the palm side of a finger or hand accompanied by loss of finger bending should be assessed urgently, as the outcome of repair is generally better the sooner it is performed.
Assessment focuses on which specific finger movements are affected, together with examination of the wound and surrounding structures, including nerves and blood vessels that run alongside the tendons.
A complete flexor tendon laceration requires surgical repair, usually performed within days of the injury, where the divided tendon ends are stitched back together.
Following surgery, a structured hand therapy programme is essential, using a splint that protects the repair while allowing carefully controlled movement of the finger. This balance between protection and controlled motion is critical to the outcome: too much movement risks the repair failing, while too little leads to stiffness and adhesions. Partial tears involving a smaller proportion of the tendon may sometimes be managed without surgery, depending on the extent of the injury.
Outcomes depend on the location of the injury along the finger, since some zones have a more challenging healing environment than others, as well as how quickly the repair is performed and, importantly, how closely the structured hand therapy programme is followed afterward. Stiffness and, less commonly, re-rupture of the repair are recognised risks. Delayed treatment generally leads to a more difficult repair and a less predictable outcome, which is why early assessment matters.
Flexor tendon injuries are usually the result of a cut close to the tendon's path just beneath the skin, and they need prompt surgical repair to restore the ability to bend the finger. Structured hand therapy afterward is just as important as the surgery itself in determining how well the finger moves in the end. Any wound with loss of finger bending should be assessed urgently.
