The Ascension® PyroHemiSphere™ is an uncemented, onecomponent prosthesis for the basal thumb joint. It has a proximal head that articulates against the trapezium, a planar collar that provides for a simple planar bone resection, and an anatomic shaped stem that is press fit into the canal of the first metacarpal following resection of the base. It is fabricated from a thick pyrocarbon layer encasing a graphite core that is impregnated with one-atomic percent tungsten so it is radiopaque. The Ascension® PyroHemiSphere™ is intended to replace the proximal end of the first metacarpal in cases of rheumatoid arthritis, traumatic arthritis, osteoarthritis or post fracture deformation or bone loss which present as either a painful, unstable thumb, or a thumb with limited range of motion.
A sterile implantable device designed to replace the proximal end (base) of the first metacarpal of the thumb carpometacarpal (CMC) joint (articulation with the trapezium) typically to treat thumb instability/motion disabilities caused by arthritis or fracture. It is typically a one-piece device, made of one or several materials (e.g., carbon, graphite, metal); implantation may be performed with our without bone cement.
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