Triquetrohamate Coalition with Lunotriquetral and Lunohamate Osteoarthritis

Abstract

In this article a case of triquetrohamate synostosis with accompanying lunotriquetral and lunohamate osteoarthritis is presented. Triquetrohamate synostosis is a very unusual type of carpal coalition. Generally speaking, carpal coalition is a condition in which two or more carpal bones fail to segment during development, resulting in congenital fusion. The incidence in general population is around 0.13%, however this can be almost ten times higher among black people [1]. The most common coalition is lunotriquetral, representing nearly 90% of all carpal synostosis, followed by capito-hamate coalition with 5.6% of all cases [1]. In the English medical literature triquetrohamate coalition has been described associated to calcaneus-cuboid coalition [2] or to hereditary symphalangism [3, 4]. None of those authors reported concomitant lunotriquetral and lunohamate osteoarthritis. What makes this case also different is the absence of associated conditions particularly since coalition between the proximal and distal carpal rows is usually syndromic [5] Moreover, lunotriquetral osteoarthritis is relatively uncommon and mainly secondary to congenitally incomplete separation of both bones [6]