Flexor tendon injuries
QT Pathologies (EN)
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 regions, turn into tendons just past the middle of the forearm, and attach into the bones of the fingers. 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.
- Anatomy of the finger flexor tendons Anatomy images courtesy and copyright of Primal Pictures Ltd – www.primalpictures.com
- Anatomy images courtesy and copyright of Primal Pictures Ltd – www.primalpictures.com
Deep cuts on the palm side of the wrist, hand, or fingers can injure the flexor tendons and nearby nerves and blood vessels.
The injury may appear simple on the outside, but is actually much more complex on the inside. When a tendon is cut, it acts like a rubber band, and its cut ends pull away from each other. A tendon that has not been cut completely through 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.
The tendons can be damaged by any cut across the palmar surface of the wrist or hand, especially at the finger creases where the tendons lie just under the skin.
Occasionally, the tendon is detached from the bone by a violent pulling injury to the finger.
A wound across the palm or fingers
Inability to bend the finger either partly or totally
Finger lying out straighter than the adjacent digits.
Pain when trying to bend the fingers
Numbness of the finger due to injury to the nerves, which lie close to the tendons.
A hand surgeon will test the tendons individually to ascertain their integrity and decide if a repair is needed.
X-rays may be taken if the injury was caused by glass.
Occasionally, ultrasound or MRI are needed to give more information about the tendon.
Cut tendons do not heal by themselves. The tension in the tendon causes its cut ends to separate, sometimes by several centimetres. Without surgical repair, there is no prospect of regaining the movement that has been lost.
Your surgeon will advise you on how soon surgery is needed after a flexor tendon is cut. There are many ways to repair a cut tendon, and certain types of cuts need a specific type of repair.
At the end of the surgery the hand and forearm are immobilised in a plaster splint that is placed over the bandages with the wrist and fingers in a slightly bent position, in order to protect the repair.
The hand therapist will usually replace the plaster splint with a light plastic splint and start a protected exercise programme within a few days of the operation. The therapy programme after tendon repair is crucial and at least as important as the operation itself, so it is vital to follow the instructions of the therapist closely. The objective is to keep the tendon moving gently in the tunnel, to prevent it sticking to the walls of the tunnel, but to avoid breaking the repair.
In addition to regaining motion of the finger after a tendon injury, therapy will be helpful in softening scars and building grip strength.
The splint is usually worn for five or six weeks, after which a gradual return to hand use is allowed. However, the tendon does not regain its full strength until three months (healing takes place during the first three months) after the repair and the movement may improve slowly for up to six months.
In most cases, full and normal movement of the injured area does not return after surgery.
Problems that can occur include :
The repair breaks:
It usually happens early on as the tendon is at its softest at this stage of healing. The patient may feel a "ping" as the repair snaps or simply notices that the finger isn't bending in the way it has been.
The tendon sticks to its surroundings and does not slide in its tunnel:
Scarring of the tendon repair is a normal part of the healing process. But in some cases, the scarring can make bending and straightening of the finger very difficult. More hand therapy may help. If therapy fails to improve motion, an operation to release the tendon from the scar tissue (tenolysis) may improve the movement, but full movement may not be regained.
During your consultation, Dr. D'Agostino will discuss the current treatment options and can help you choose the best treatment based on your particular case.
- Functional extension deficit of the fourth finger secondary to scar adhesions of the flexor tendons
- Release of adhesions by Teno-arthrolysis of the fourth finger