What is it?
  • Tendons are what let you bend and straighten your fingers. In a sense, you operate your fingers by remote control - the muscles which move your fingers are located up in your forearm, not in your fingers.
The flexor tendons are smooth, flexible, thick strings which bend your fingers - they look a bit like clothesline rope. They work like a bicycle brake cable to bend your fingers, sliding in and out of the finger as it straightens and bends. If a flexor tendon is cut in half, the end connected to the muscle is often pulled back into the palm - no way to heal on its own. This is a very precision mechanism, and it doesn't take much to gum up the works. Even a cut only part way into the tendon can be a big problem.
  • The most common and difficult problem that people have after a tendon injury is stiffness - losing the ability to either fully bend or straighten the finger - which can be permanent. This is a possible problem for anyone who has had a flexor tendon injury. Surgery and other special treatment is usually needed to make this as little a problem as possible.
What caused it?
  • Most often, flexor tendons are damaged from a cut. Fingers have special creases which let the skin fold when you make a fist - at these points, the tendons are just beneath the skin, and are easily injured by even a small cut in the skin.
  • Less often, flexor tendons may tear or be torn off the bone by a sudden pull against a strong grip, without tearing the skin.
What can you do to help?
  • Ice, elevation, and have it checked out by a doctor. If the injury involved a cut, medical evaluation is particularly important - to check whether or not a tetanus shot, antibiotics or other treatment is required, even if stitches aren't needed.
  • After injury, if surgery is needed, there is a limited amount of time to operate and get the the best possible result. Surgery delayed for more than two weeks has less of a chance of having a satisfactory outcome.
What can a therapist do to help?
  • Surgery is only half the battle for this problem. Therapy is a necessary and essential treatment for most people recovering from a flexor tendon injury.
  • Special hand therapy usually involves making one or more custom splints, performing and supervising special exercises, and making the hand feel better in general.
What can a doctor do to help?
  • Confirm that this is the problem, and check for nerve injury or other problems which can occur at the same time.
  • Treatment really depends on the type of  injury. Your doctor may recommend:
    • Moving the fingers and doing exercises right away.
    • Hand therapy.
    • A splint or a cast, along with special exercises.
    • Performing surgery to repair the damage.

Sewing a cut flexor tendon together is something like sewing two small ropes together, end to end. Special stitches are used on both the inside and the outside - but even with the best stitches, the repair can still be pulled apart if it is not protected by a special splint. It can take as long as two months before healing has made the repair strong.
Sometimes the end of the tendon is cut or pulled off the bone. This may require stitches through the bone or a special implant to anchor the tendon back to the bone.

How successful is treatment?
  •  It depends on many things - getting full motion back is less likely if
    • there is a nerve injury or a broken bone next to the tendon injury
    • there is a long healing period before surgery
    • the person is prone to thick scars
    • the damage was caused by a crush injury
    • there are problems participating in hand therapy after surgery
The location of the injury also has a big influence on how well people recover after surgery - cuts in the fingers don't do as well as those in the forearm. These locations are referred to as "zones", as shown in this diagram. The areas shown in red are referred to as "no man's land" - because stiffness is such a common problem after injuries in this area.
    • In addition, there are many other factors which can also affect the odds of having a good result versus a stiff hand. 
  • After a flexor tendon injury, most people lose some movement in the finger, despite all efforts. It really takes everything going in your favor, including luck, to have a full recovery. However, if all goes well, the hand will work better after surgery than if surgery were not done, and that's the reason for doing it.
  • "I'm upset. It's been months since my surgery and my finger is still stiff and bent. When is it going to be normal?". 
    • Reality check: Many finger flexor tendon injuries do not sound all that bad, but in fact present a terrible problem - technically difficult to repair, requiring an extraordinary amount of therapy, and often not resulting in a full normal perfect recovery. You had a serious injury. Your finger may never be the same as it was before the injury. However, it will be better than it is now, and you will adapt. Recovery of function is more related to your brain's ability to adapt than your finger's ability to bend. That's how people return to productive, satisfying lives after having half of their hand blown off. After a serious hand injury, motivation to get better is critical: the more you work on your own recovery, the more likely your recovery will be satisfactory. Focus on what you can do, not what you may have lost. Get on with your life. If you're not working because of the injury, get back to work in any capacity possible. Don't keep your life on hold waiting for a full recovery or for more surgery to solve your problems. 
    • There is hope: Most hand tendon injuries take longer to recover than most other operations elsewhere in the body. The entire process can be very stressful. Two months after tendon surgery is the usual time that many people run out of steam, lose faith and get depressed about their recovery - this is normal. If you feel that this event has triggered a clinical depression, get professional help for this - it will help your recovery, not to mention your emotional well being, and you still may have a way to go - final plateau of recovery may take about a year. Don't let your finger take over your life - you will eventually find that you will be able to do much more with your hand than you currently think possible, despite the changes brought on by the injury. 
What happens if you have no treatment?
  • It depends on what has happened, but unlike other injuries in the body, cut tendons don't heal well on their own.
  • If the tendon has been cut through and through, you won't be able bend one or both of your finger knuckles again.
  • If the tendon is cut part way through, it may heal up on its own, or it may tear apart completely a week or two later - or it may get stuck and stop working.
  • If you decide to have surgery later, it is much more of an ordeal - two operations instead of one, and twice as long to recover.
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