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Total wrist arthroplasty (TWA) aims to restore pain-free motion to diseased joints. One such TWA, the Motec, has demonstrated good results with acceptable complication rates. It has recently been suggested that the metal-on-carbon fibre reinforced poly ether ether ketone (Mo-CFR-PEEK) version of the Motec TWA be implanted instead of the metal-on-metal version. An explant analysis was undertaken on seven Motec Mo-CFR-PEEK TWAs, revised for a variety of reasons, after a mean time of 2 years in vivo. Compared to a new Motec implant, five of the explanted metal heads and three of the CFR-PEEK cups became smoother in vivo, suggesting self-polishing and negative skewness, indicating some material loss in vivo. Two explanted cups showed indentation marks on their rims and one of these was from component impingement with embedded metallic debris. In the short-term, the articulating surfaces of Motec Mo-CFR-PEEK TWAs did not show major damage. Level of evidence: IV., Competing Interests: Declaration of conflicting interestsThe authors disclosed the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: DJB has a paid consultancy role with Swemac. He receives no royalties for the use of any wrist replacements.

The ReMotion wrist replacement has good short- to medium-term survival with an acceptable complication profile as we previously reported in a cohort of patients with rheumatoid arthritis. We now report the long-term results of the same cohort and details of explant analysis of revisions undertaken for aseptic loosening. A total of 16 wrists were reviewed. Seven prostheses remain in situ with no obvious signs of wear or radiological loosening at a mean follow-up of 15.5 years. Three wrists had been revised: one for infection and two for aseptic loosening. Five patients (six wrists) died 2-9 years after operation from unrelated causes. Explant analysis demonstrated relatively minor wear compared with the published results of the Universal-2 prosthesis. We hypothesize that this may be explained by differences in polyethylene sterilization and prosthetic design. The ReMotion wrist replacement has favourable long-term results in patients with rheumatoid arthritis with a 16-year survival rate of 78%-86%. Level of evidence: IV., Competing Interests: Declaration of conflicting interestsThe authors disclosed the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The senior clinical author (DJB) has a paid consultancy role with Swemac, a manufacturer of an alternative wrist replacement. He receives no royalties for the use of any wrist replacements.

Single-piece silicone implants dominate metacarpophalangeal joint arthroplasty. The NeuFlex® implant was introduced to improve on the clinical performance of other silicone implants by having a pre-flexed hinge. By visually examining a cohort of 30 explanted NeuFlex® metacarpophalangeal joint prostheses we sought to identify the failure modes of these implants. Seven were not fractured, 11 had fractured across the hinge, nine had fractured at the junction of the distal stem and the hinge, and three showed fractures at both the hinge and at the junction of the distal stem and the hinge. These data may prove helpful in identifying how the performance of single-piece silicone implant designs can be improved.