Bilateral STT Arthrodesis in a Young Patient with Occult Proximal Row Coalition.

Carpal coalitions have an incidence of 0.1 to 1% in Caucasians and up to 8 to 9% in African populations. They rarely cause clinical problems requiring investigation or treatment, but are commonly identified on imaging obtained for other indications.  We report a case of a 35-year-old male with progressive degenerative change of incomplete coalitions of the scaphotrapeziotrapezoid joint (STT) in the presence of bilateral complete osseous lunate-triquetral coalitions (Minnaar type 4). He was successfully treated with staged bilateral arthrodesis with excellent symptom resolution and preservation of function.  In patients with isolated STT coalition six reports of surgery exist, two of which were for arthrodesis. This is the first described case of STT arthrodesis in a patient with coexistent lunate-triquetral coalition.  The STT arthrodesis remains a safe and effective treatment for STT pain even in cases of occult carpal coalition. Functional range of movement was well preserved.  This is a Level V study.