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| Tendon & Ligament Injuries > Flexor Tendon Injuries What are Flexor Tendon Injuries? Tendons in the hand connect with muscles of the forearm, enabling you to bend and extend your fingers and lift your hand at the wrist. The flexor tendons are smooth, thick flexible strings, running through six lubricated tunnels or compartments (flexor tendon sheaths). They work like bicycle brake cables to bend your fingers, sliding smoothly within the fingers as they straighten and bend. Because this is a very precise mechanism, dependant upon the muscles of the forearm and many coordinated parts, injuries to a tendon or its sheath can cause major problems in the hand. If untreated, a flexor tendon is unlikely to heal on its own. A complete cut through the tendon results in the inability to bend one or both of the finger knuckles. Incomplete lacerations may heal initially, only to tear apart later in an injury that presents further complications. Sometimes the tendon gets "stuck" and stops working. If you wait before undergoing surgical intervention, treatment becomes much more of an ordeal, often involving two operations rather than one. Healing time will be greatly extended. Causes of Flexor Tendon Injuries? Flexor tendons are damaged most often by incision. Because the tendons are located just beneath the skin of the finger and hand, they are easily affected even by small cuts. The fingers have creases allowing the skin to fold when they bend; at these points on the underside of the fingers the tendon is just beneath the surface of the skin. If a flexor tendon should be severed, it is likely to retreat back into the palm where it connects to the muscle of the forearm. When this happens, there is no way for the tendon to heal on its own. Flexor tendons occasionally rupture or are torn off the bone by a sudden pull against a strong grip. The tendon may be injured without any break to the skin. Risk increases with contact sports such as football, rugby, or wrestling. A classic example of tendon rupture is known as "jersey finger." It occurs when a football player grabs another player's uniform, catching the ring finger and rupturing the flexor digitorum profundus (FDP) tendon at the DIP (distal interphalangeal) joint at the tip of the finger. These injuries are often diagnosed late, as the patient first considers the finger to be merely "jammed." Sometimes the laceration of a tendon goes unnoticed, only to present later as a spontaneous rupture. Rheumatoid arthritis, a degenerative autoimmune disease which attacks the lining of the body's joints, may also result in injuries to the flexor tendons. These tendon injuries are often "silent"; the patient is aware of the fact that the finger no longer bends properly, but is unable to recall an exact moment of injury. Symptoms of Flexor Tendon Injuries? It is useful to consider the anatomy of the finger when differentiating among flexor tendon injuries. Each finger has two flexor tendons, while the thumb has only one. The longest tendon in the finger is the FDP, which flexes all of the joints: the DIP joint at the tip of the finger, the PIP (proximal interphalangeal) joint in the middle, and the MP (metacarpal phalangeal) joint where the finger joins the hand. The other tendon, called the FDS (flexor digitorum sublimus), flexes only the DIP and the MP joints. It the FDP tendon is severed, it is still possible to flex the PIP and MP joints, but not the DIP joint. If the FDS is cut, flexion is retained in all three joints. The FDP tendon passes through the FDS at the approximate midpoint of the finger. Severing both tendons affects all the joints of the finger. Because the nerves in the fingers are so close to the tendon sheaths, injuries to the nerves are often associated with flexor tendon injuries. If a nerve is injured, you may experience numbness. The most common problem people have after a tendon injury is stiffness and an inability to fully bend or straighten the finger. If the finger has been cut, there is an open laceration. Treatment of Flexor Tendon Injuries? If you have experienced any injury of the hand or wrist, it is essential to seek medical treatment immediately. Many tissues quickly lose their elasticity, and prompt treatment is necessary to limit damage. Injuries to the hand, wrist, and forearm involve many related components and potential complications. The results of surgery are maximized if it is performed as soon as possible, within two weeks after injury at most. Use ice and compression to help slow the flow of blood to the damaged site. In the case of an open wound, a tetanus shot, antibiotics, or other treatment may be required. Your doctor will examine the hand, ask about the nature of the injury, and inquire about any previous conditions of the hand, wrist, or arm. The principal goal of initial treatment is to correctly identify the condition and evaluate the wound for surgical repair. The injury is cleaned and, if necessary, sutured. The hand, wrist, and forearm are immobilized with a splint holding the hand in a downward position. Flexor tendon injuries require surgical repair. Sewing a cut flexor tendon together is not unlike sewing two small pieces of rope together, end to end. The special stitches used on both the inside and outside of the repair can be pulled apart if the hand is not protected after surgery by a splint. Time is needed to strengthen the repair, and the splint may be required for as long as two months. If a tendon has been cut or pulled off the bone, stitches through the bone or a special anchoring implant may be necessary. The specific location of the injury has a big influence on postoperative recovery, as do the details of impact on surrounding tissue, such as damage to associated nerves and bones. Injuries that involved crushing present particular challenges. Surgery alone is not enough to assure recovery after flexor tendon injuries, although the hand will undoubtedly work better as a result of surgical repair. Rehabilitation is also essential, and involves learning how to rebuild strength and dexterity in the hand. Special custom splints are often devised, and a therapist helps you retrain the hand and fingers, perform particular exercises, and relieve the discomfort associated with this condition. He or she will recommend specific heat treatment to be applied through the splint. Once the splint is removed, therapy and rehabilitation should continue. Ice massage is helpful before and after exercising the hand. Many factors, including luck, affect the outcome of treatment for flexor tendon injuries. The problem must be discerned quickly, treatment must be prompt, and patient commitment to rehabilitation must be complete. If all goes well, the hand will be restored as much as possible to its former condition. The information provided herein is not intended to be a substitute for professional medical advice. You should not use this information to diagnose or treat a health problem or disease without consulting a licensed physician. ©2000 DynoMed.com, LLC, Indianapolis, IN |