The extensor tendons are attached to muscles in your forearm and run across the back of your hands into your fingers. These tendons enable you to straighten your fingers and thumbs. Inside the fingers, the tendons are thin and flat and are joined by smaller ones that attach to the hand muscles and permit coordinated fine finger movements.
Since the extensor tendons sit above the bone, just beneath the skin, they are in a vulnerable position and can be easily injured, even by something as minor as a small cut. These tendons can also be detached from the bone. Detachment of extensor tendons can happen when a finger, for example, gets jammed. When this happens, patients find it difficult to straighten their knuckles. Individuals who have injured their extensor tendons find treatment to be, not only necessary, but extremely helpful.
If a tendon is cut, it may require stitches. However, splints are used to treat most tears that result from jamming one's fingers. Using a splint will keep the end of the tendon that is healing from pulling out of place. Splints have to be worn all of the time until complete healing of the tendon is achieved. Typically, your hand surgeon will place the splint in the proper location. When necessary, surgeons place a pin through the bone across the joint so as to serve as an internal splint.
If the extensor tendon has been cut, has come off the bone, or has pulled part of the bone off, the fingertip on the finger affected will droop. This condition is called "mallet finger", and is usually treated with a splint that keeps the fingertip straight until the tendon heals. If the tendon was cut, stitches may be required to repair the injury. The length of time the splint needs to be worn and how big it is depends on how and where the tendon was injured, but the splint should be kept on for the four to eight weeks or more it takes for complete healing. If the splint is taken off any earlier than the amount of time recommended by your hand surgeon, the fingertip may droop again and need more splinting.
Other times when the extensor tendon is cut or torn, the middle joint of the finger may bend down in a flexed position, called a boutonnière deformity. This condition may also require the use of stitches, but a splint to hold the middle joint straight is necessary to complete the process. If the splint isn't worn continually, for approximately four to eight weeks, the finger can bend down even more and become fixed in that position.
If the extensor tendon was injured because of a cut on the back of the hand, it may be difficult or impossible to straighten out the finger at the large knuckle where the finger meets the hand. An injury like this, in addition to a splint, usually requires stitches to hold the ends of the tendon together. The splint may hold both the finger and wrist in place or it may be a dynamic splint, which allows the fingers to move a little while still protecting the tendon until it heals.
As it heals, the extensor tendon may attach itself to a bone or scar tissue in the area of the injury. Because other factors, such as infections or fractures, play a role, each injury is unique. Even when a patient receives the best possible treatment, the formation of scar tissue may restrict the ability to bend or straighten the fingers. Therapy can greatly improve finger motion; surgery can remove or free the scar tissue that is keeping the fingers in place. When one of our hand surgeons discusses your particular case with you, he will explain the risks, results, and side effects that you should expect from your course of treatment.