Impingement-related osteolysis in Motec total wrist arthroplasty: an explant analysis and review of the literature.

We present five cases of osteolysis in the Motec total wrist prosthesis, three around the radial implant, one around the metacarpal implant and one around both. Three of these were progressive and required revision, and biomechanical explant analyses of these revised prostheses were performed. Ex vivo testing of the contact points of the Motec implants was also performed at maximum extension. Here, impingement occurs between the metacarpal screw and the dorsal rim of the cup (non-articulating surfaces) with the short-necked prosthesis, leading to metacarpal screw damage, titanium debris formation and osteolysis. An analysis of three previously published cases suggests that this may have been the likely mode of failure in those cases. This complication is preventable by avoiding use of the short-neck prosthesis.Level of evidence: IV.