The Guepar group heritage: 20 years of clinical evidence Indicated in the surgical treatment of the trapezio-metacarpal joint rizarthrosis for the aged and active patient, but not force-worker, the ISIS prosthesis was developped based on the results of the Guepar group's developments (www.guepar.org). Compared to the original Guepar prosthesis, ISIS enables the trapezial cup to be implanted without bone cement. Characteristics of the ISIS semi-constrained joint including a large diameter head which provides a large articular mobility of 68° anatomically shaped metacarpal stem coated with porous titanium for cementless use metacarpal collar to prevent any stem subsidence modular necks available in 2 lengths and 2 offsets trapezial cup available in cemented and cementless versions, any of which designed with low profile cementless cup designed for important primary stabilty with threaded fixation