Flexor Carpi Ulnaris (FCU) Tendinosis

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, such as consulting with a medical professional
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.

Please keep the wound clean and dry for 24 hours. Bathing is safer than showering. Wrap a towel around the dressing in case any water gets in, then place a plastic bag over the hand and secure it tightly with rubber bands. After 24 hours, the dressings can be removed and the incision can get wet in the shower. Blot it dry. There are no stitches to remove (they’re buried and absorbable). There’s a piece of tape over the wound. The tape will fall off when it’s ready. The longer it stays on, the nicer the final wound may look. Please don’t submerge the incision under water (like swimming or putting your hand under water) for 10 days after surgery. Heavy activities should be avoided for 1-2 weeks. If you have any concerns or questions during the healing process, it is advisable to consult with a medical professional.

While less common than other tendon problems about the wrist, FCU tendon pain can be 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. If non-operative measures are pursued, options such as rest, immobilization, physical therapy, and anti-inflammatory medications may be recommended. However, in cases where surgical intervention is necessary, consulting with a specialized hand surgeon to discuss the procedure would be advisable.

Reference 1: Flexor Carpi Ulnaris Tendinopathy, Budoff JE, Kraushaar BS, Ayala G, The Journal of Hand Surgery, Vol 30A(1):125-129, 2005.