The ulnar corner is complex with many anatomical structures and many potential pathologies. This may render diagnosis and treatment a challenge. Meticulous history taking and examination are required, supplemented, if necessary, by tests such as X-ray, MRI, and arthroscopy. Condition include ECU and FCU tendinopathy; hook of hamate fracture; carpal instability; osteoarthritis of the DRUJ, pisotriquetral joint and lunatehamate joint; degenerative and traumatic lesions of the TFCC; ulnar neuropathy, and hypothenar hammer syndrome. Successful treatment depends on accurate diagnosis; non-operative measures usually suffice but surgical options include excision arthroplasty (e.g. pisiform arthritis), joint replacement (e.g. ulnar head), neurolysis (e.g. ulnar nerve neuropathy), surgical debridement (e.g. TFCC central perforations and lunate–hamate arthritis), and ulnar shortening (ulnocarpal impaction).
Non-union in a hook of hamate fracture of a skeletally immature baseball player
