Extensor Carpi Ulnaris Instability Following Ulnar Shortening Osteotomy.

Background  Ulnar shortening osteotomy (USO) is a well-established procedure for the treatment of ulnar impaction syndrome. Although uncommon, the procedure can be associated with complications including nonunion, malunion, and hardware irritation. Case Description  We present a 56-year-old woman who developed extensor carpi ulnaris (ECU) tendon instability following an USO. Literature Review  The etiology of such a complication can be multifactorial. Clinical Relevance  The recurrence of ulnar pain following an USO should raise the suspicion of possible ECU instability within the differential diagnosis.