The EPL (extensor pollicis longus) tendon is the structure that extends the thumb and keeps it from falling into the palm. 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 can rub across a bone spur until it abrades and fails. In cases of fracture, the swelling from the fracture cuts off the EPL tendon’s blood supply so that it ruptures after a few weeks or months.
EIP to EPL Tendon Transfer
When the EPL tendon ruptures the thumb can’t extend or 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 tendon tissue has been lost and a repair would make the tendon too short. A tendon transfer uses a nearby tendon to substitute for the damaged tendon, essentially ‘robbing 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. No significant loss of index finger function occurs.
This tendon transfer is a relatively quick outpatient procedure that is not very painful at all. It does, however, require some 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 and heavy work may be resumed after 4 months.
After surgery, the wound should be kept clean and dry for 3 days. Bathing is safer than showering, because the hand can be kept out of the bath tub. Wrap a towel around the hand and then place it inside a plastic bag secured with rubber bands. If a bathtub is not available, the best cast protector is made by Walgreens. After 3 days the wound can get wet in the shower, blotted dry, and band-aids or a light dressing that will not limit motion can be applied. Please do not get the wound dirty, or submerge it under water, until the stitches come out, 2 weeks after surgery.
While the thumb doesn’t move totally normally following this tendon transfer (perfection is an elusive goal), the thumb’s 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 the EPL ruptures, leading to hand dysfunction because the thumb gets in the way, know that this problem has a very effective solution.