Tendons are strong, cord-like bands of connective tissue that link muscle to bone, translating muscle contractions into finger movement. In the fingers, two main groups operate: the flexor tendons, which run along the palm side and allow the finger to bend, and the extensor tendons, which run along the back of the hand and allow the finger to straighten. A laceration that severs one or both structures immediately disrupts this mechanical chain, making it impossible for the muscle to pull the bone and compromising the finger’s function. Because tendons are under constant tension, a clean cut causes the severed ends to retract away from the injury site, preventing them from healing naturally.
Recognizing a Severed Tendon
The most immediate symptom of a severed tendon is the inability to move the affected finger joint voluntarily. If a flexor tendon is cut, the finger remains straight, and the person cannot curl it into a fist. Conversely, an extensor tendon injury prevents the finger from fully straightening. This loss of active motion often results in the finger lying in a visibly straighter position compared to adjacent, uninjured digits.
Severe pain is concentrated at the site of the laceration, typically located on the palm, wrist, or along the finger. Since nerves and blood vessels run in close proximity to the tendons, a deep cut frequently damages these structures as well, leading to numbness in the fingertip. The wound may appear ragged or deep, and swelling and bruising commonly develop quickly around the injury site.
Immediate First Aid Steps
The first step is to control bleeding by applying direct, firm pressure using a clean cloth or sterile dressing. The injured hand should be elevated above the heart to slow blood flow and minimize swelling. Do not remove any large, embedded debris; instead, clean the area gently around it with water or a sterile saline solution.
Once the wound is dressed, the hand must be kept still. If a splint is available, use it to immobilize the hand and finger to prevent further damage or movement of the severed tendon ends. Immediate emergency medical attention is necessary for any deep cut that may involve tendons, nerves, or blood vessels, as early treatment improves the long-term outcome and reduces the risk of infection.
Surgical Repair Procedures
Upon arrival at the hospital, the injury is assessed through a physical examination to test the function of the flexor and extensor tendons. X-rays are often taken to check for associated bone fractures or to locate foreign bodies, such as glass fragments. Surgical repair is the definitive treatment for a severed tendon, as the separated ends cannot heal on their own due to tissue tension.
The procedure is performed by a specialized hand surgeon, typically under regional or general anesthesia. The surgeon cleans the wound and enlarges the incision to locate the retracted tendon ends. Using sutures finer than a strand of hair, the two ends are carefully stitched back together in a process known as primary repair. The procedure is generally performed as soon as possible, ideally within days, to prevent the tendon ends from developing excessive scar tissue.
Post-Surgical Recovery and Rehabilitation
Following tendon repair surgery, the hand and forearm are immediately placed in a protective splint or cast, which holds the repaired tendon in a position of minimal tension. This period of immobilization is necessary to protect the fragile repair, as the stitches alone are initially the only connection holding the tendon ends together. The splint is usually worn constantly for the first four to six weeks, during which the tendon begins the slow process of healing.
After the initial immobilization period, specialized hand therapy begins, often guided by an occupational or physical therapist. The purpose of this therapy is to perform controlled, gentle movements to prevent the repaired tendon from adhering to the surrounding tissues, a complication known as tendon adhesion. Adhesion can severely limit the finger’s range of motion, so the therapist will prescribe specific, frequent exercises to encourage the tendon to glide freely within its sheath.
Returning to normal function requires patience, as it can take up to three months for the repaired tendon to regain significant strength. Full use of the hand, including heavy lifting or gripping, is typically restricted for up to 12 weeks. The process of fully regaining range of motion can continue for six months or longer.