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Trigger Thumb in Children

Trigger Thumb in Children

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A trigger finger is a condition where a finger is stuck in a bent position as if pulling a trigger. The tendon in the finger, the tough fibrous tissue that controls the finger's motion, becomes irritated and may swell up in the opening of the passage through the finger. As it becomes inflamed, the tendon can thicken and then get caught in the opening. When the situation isn't severe, it is possible to straighten the finger and you may even feel a popping sensation as the tendon is released from the opening. but in severe cases, the finger remains bent.

Although the cause of trigger finger isn't really known, doctors do know that people who use repetitive motions with their hands and fingers are more prone to developing the problem.

The author of this article wrote about a 13-month old boy who was originally seen because he had a "crooked thumb." When the parents were questioned, they mentioned that for the past three months, they noticed that the child was having difficulty extending his thumb and that when he did, they could sometimes hear a clicking or popping sound. No treatment has been done and the child is being considered for surgery to correct the problem, diagnosed as trigger finger.

Since doctors don't know what causes trigger finger, this case is interesting because it puts into question how trigger finger starts. Is it something that someone is born with, perhaps (a congenital condition)? Is a child's trigger finger different from an adult's? And how and when can surgeons tell if surgery is the right step? Some studies have shown that there is no congenital trigger thumb and that even a child's trigger thumb is caused by something. Estimates are that about three out of every 1,000 children born will develop the condition. There isn't any agreement on the reason why they develop it though. Some researchers feel that the tendon and the sheath around it are mismatched, causing irritation, while others feel that there is a degeneration of tissue because of the way a baby holds his or her thumb in the early years.

Right now, there are many opinions about how to treat trigger finger in a child. Some surgeons prefer not to do surgery and would rather try other options, such as watchful waiting (not doing anything unless the condition gets worse), stretching the finger, or splinting it. Using this approach, it's felt that the condition will fix itself. Other surgeons, however, feel that the best treatment is surgery, releasing the tendon so that the finger has full range of motion again.

One study, by Dinham and Meggitt, reviewed 131 thumbs with trigger finger on 105 children. Twenty-six thumbs were left as is and observed, rather than treated. Of these 26, 19 cleared up on their own. One hundred five thumbs were treated with surgery and 100 had full recovery. Other studies show different numbers of the thumbs healing on their own, or spontaneous resolution. The numbers range from zero to 66 percent.

When treating a trigger finger with exercises and splinting, the results vary considerably. In one study of 58 thumbs in 46 children by Watanbe, the results were originally reported as "satisfactory" in 96 percent of the thumbs, but when looking at the data further, it was found that 34 of the thumbs, 59 percent, were not with normal function. Yet another study by Nemoto and colleagues, described nighttime splinting of 40 thumbs for about 10 months. They, too, reported a good success rate (73 percent), but several patients were not accounted for in the final results. Finally, a third study by Lee and colleagues, looked at full-time splinting, not just at night, in 31 locked thumbs. The results of this study of six to 12 weeks found that 71 percent of the thumbs had improved, but full motion was not found in all thumbs.

Surgery, usually recommended if the trigger finger is still present after a year, can vary according to the surgeon. Usually, surgery is quite effective. A study by McAdams and colleagues followed for 15 years children who had the trigger finger released. The surgeons had released 30 thumbs in 21 children. Their findings, after 15 years, was that no-one had a return of the trigger finger and all had good use of the affected thumb or thumbs, although 23 percent did have a bit of trouble straightening out the thumb and 18 percent could hyperextend the finger. Other similar studies had similar findings. However, one study done by van Loveren and van der Biezen has found that the simple surgery done by most surgeons, a release that allows the tendon to move freely, may not be enough. They found that of their review of 16 patients, 69 percent needed a release of the area around the first part that was released. Lastly, some surgeons say that the surgery may not be necessary at all, but that using a needle, they can fix the problem.

The author writes that it's obvious that there are several limitations to the available studies so it's not possible to come up with a definitive optimal treatment for trigger finger of a child's thumb. Further study is needed comparing the types of treatments, the results, and the long-term outcomes.

Reference: Donald S. Bae, MD. Pediatric Trigger Thumb. In Journal of Hand Surgery. September 2008. Vol. 33A. No. 7. Pp. 1189-1191.