The EPL (extensor pollicis longus) tendon extends your thumb. Following a wrist fracture, or sometimes due to arthritis and bone spur formation, the EPL tendon can rupture. In cases of arthritis, the EPL tendon rubs can rub across a bone spur until it abrades and fails. In cases of fracture, the swelling cuts off the EPL tendon’s blood supply so that it ruptures after a few weeks or months.
When the EPL tendon ruptures the thumb can’t extend and the thumb can’t be brought out of the palm. The thumb gets in the way of using the hand, which makes many activities very difficult to perform. Fortunately, this is a very treatable problem using a ‘tendon transfer’.
When a tendon ruptures because of abrasion or lack of blood supply, a large area of the tendon is damaged, not just a small piece, as would happen if the tendon were, for example, cut by a knife. And when a large area of the tendon is damaged , it can’t simply be repaired, because the tendon would now be too short. So we use a nearby tendon to substitute for the damaged tendon. This is known as a ‘tendon transfer’, where we essentially ‘rob from Peter to pay Paul’. In this example, the index finger has two tendons that extend it, so one of these can be used as a ‘spare part’ and transferred to the stump of the EPL tendon on the thumb.
This is a relatively quick outpatient procedure that is not very painful at all. It does, however, require a fair amount of hand therapy afterwards. A special dynamic splint (with a rubber band to take the stress off of the repaired tendon during thumb extension) needs to be worn for 4 weeks. After 4 weeks the hand can be used for light activities, with full activities usually allowed after 3 months. A night splint is worn for 3 months. Athletics can be resumed after 4 months.
While the thumb doesn’t move totally normally following this tendon transfer (perfection is an elusive goal), the situation is almost always greatly improved and patients are usually very happy because they can now extend their thumb and get it out of their palm. This allows them to use their hand again.
So, if your EPL ruptures and you can’t use your hand effectively because your thumb gets in the way, know that this is a not uncommon problem with an effective solution.