Flexor Carpi Ulnaris (FCU) Tendinosis

The flexor carpi ulnaris (FCU) tendon is on the palmar side of your wrist, above the small finger. It is one of the major tendons that flexes your 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’ by it (see previous blog on the FCR tendon), 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.

Initial treatment is usually a steroid injection and physical therapy. The strengthening exercises are easy and can be learned in 1-2 visits, and then performed every day at home. They should take no longer than 5 minutes each day. If the FCU pain doesn’t resolve after a few months, then a surgical option may be considered.

Fortunately, there is a quick, effective, minimally-invasive outpatient surgical option available that is not very painful. 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 a few days after surgery, and then normal activities can be restarted, as tolerated.

So if the FCU tendon is causing pain, it can be effectively treated either nonoperatively, or with a small outpatient surgical procedure. Either way, this pain from overuse 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.