Flexor Tendon Injuries


Flexor tendons in the hand and forearm:

The muscles that bend or flex the fingers are called flexor muscles.These flexor muscles move the fingers through cord-like extensions called tendons, which connect the muscles to bone.The flexor muscles start from the elbow and forearm, turn into tendons just past the middle of the forearm, and attach onto the bones of the fingers (See Figures 1 and 2). In the finger, the tendons pass through fibrous rings called pulleys, which guide the tendons and keep them close to the bones, enabling the tendons to move the joints much more effectively.

Deep cuts on the palm side of the wrist, hand, or fingers can injure the flexor tendons and nearby nerves.The injury may appear simple on the outside, but is actually much more complex on the inside.When a flexor tendon is cut completely, it acts like a rubber band, and its cut ends pull away from each other.A tendon that has been partially cut may still allow the fingers to bend, but can cause pain or catching, and may eventually tear all the way through. When tendons are cut completely through, the finger joints cannot bend on their own.

Treatment

Tendons are living tissue. If the cut ends of a tendon are brought back together, healing can occur. Because of the separation that occurs after a complete flexor tendon laceration, the tendon cannot heal without surgery.

It is important to preserve the pulleys in the finger, and there is very little space between the tendon and pulley in which to perform a repair. Nearby nerves may need to be repaired as well. After surgery, the injured area can either be protected from movement or started on a very specific limited-movement program. Your doctor will prescribe hand therapy for you after surgery.

IF YOU TRY TO MOVE YOUR FINGER TOO SOON AND DO NOT FOLLOW THE THERAPIST’S INSTRUCTIONS, THE REPAIR WILL PULL APART!

This is a major problem and results in more surgery and permanent loss of finger function. After six weeks, the fingers are allowed to move slowly and without resistance. Healing takes place during the first three months after the repair.

In most cases, full or nearly full motion of the injured finger will be regained after surgery and appropriate therapy. If good motion is not obtained after appropriate surgery and therapy, it means that the repaired tendon has either pulled apart or is caught in scar tissue. It may be necessary to perform an ultrasound or MRI to evaluate the tendon to see which of these has occurred. In some cases, a scarred tendon can be freed with additional therapy. If good motion is not obtained with therapy, then surgical exploration may be necessary. If the tendon has pulled apart, it is often necessary to perform a two-stage surgery where an artificial tendon is implanted, followed later by tendon grafting. If the tendon is caught in scar tissue, this can be often freed by a surgery known as a tenolysis. Even with appropriate surgery and therapy, approximately 15% of flexor tendons will become caught in scar tissue and require a tenolysis.

Therapy After Surgery

In most cases, a program of limited motion will start seven to ten days after surgery.This will involve the use of a specialized splint to allow the fingers to be passively bent with rubber bands; a small amount of active extension of the fingers will be allowed within the splint. This program helps to minimize the chance that the tendon will become caught in scar tissue.The tendon repair can pull apart if the hand is used too soon or therapy guidelines are not followed. In addition to regaining motion of the finger after tendon injury, therapy is also important to soften scars and build grip strength.

In summary, flexor tendon repairs require surgical treatment and significant follow-up therapy. To obtain the best possible result, the patient must cooperate with the therapist and understand the goals of therapy. With good compliance, an excellent result can be obtained after flexor tendon repair.