The Flexor Carpi Ulnaris (FCU) tendon is on the palmar side of the wrist, on the small finger side. The FCU is one of the major tendons that flex the wrist. Occasionally, overuse can cause damage to the FCU tendon. As opposed to the Flexor Carpi Radialis (FCR) tendon, which runs in a sheath and can get “pinched” inside of it (see the website section on FCR Tendinitis), the FCU tendon has no sheath. FCU overuse leads to painful degeneration of the FCU tendon itself, similar to the tendon degeneration found in tennis elbow and painful rotator cuffs. This is called “tendinosis”.
The initial treatment of FCU Tendinosis is non-operative, and includes a steroid injection and physical therapy to strengthen the forearm muscles. These strengthening exercises are easy and can be learned in 1-2 therapy visits, and then performed every day at home. They should take no longer than 5 minutes each day. There’s no need to spend a lot of time or money on therapy. If the FCU pain doesn’t resolve after a few months, a surgical option may be considered.
Fortunately, there is a quick, effective, and minimally-invasive outpatient surgery available that is very effective. In fact, I published a study on this procedure in 2005.1 All patients who had this procedure performed had excellent pain relief. The degenerative part of the tendon is removed through a small incision and the remaining good part of the tendon repaired. A splint is worn for 3 days after surgery, and then normal activities can be restarted, as tolerated.
Following surgery, the wound should be kept clean and dry for 3 days. After 3 days the dressings can be removed and the incision can get wet in the shower. After showering, blot it dry. There’s a piece of special tape over the wound. The longer it stays on, the nicer the wound will do. It’ll fall off when it’s ready. Don’t submerge the incision under water (i.e. no swimming or putting the hand under water to do dishes) for 10 days after surgery. The stitches are absorbable: There are no stitches to remove. Heavy activities should be avoided for 1-2 weeks.
While less common than other tendon problems about the wrist, FCU tendon pain can problematic. Fortunately, it can be effectively treated either non-operatively or with a small, outpatient surgical procedure. Either way, this overuse tendon problem can usually be cured.
Reference 1: Flexor Carpi Ulnaris Tendinopathy, Budoff JE, Kraushaar BS, Ayala G, The Journal of Hand Surgery, Vol 30A(1):125-129, 2005.