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Animal experiment: Surface wear analysis1415The linear and volumetric UHMWPE wear of one fossa could not be analyzed because the software was not able to retrieve a ‘best fit’ between the design and the scan of the explanted fossa. The error margin in the overlap between the two STL models was too large to provide reliable results due to the intraoperative trimming of UHMWPE in non-load-bearing regions, as well as the posterior UHMWPE ridge being erroneously trimmed down during the post-euthanasia implant retrieval as well as the titanium part for fixation onto the zygoma. (Fig. 3) While this does not affect the articulating surface, the difference between the ‘design-STL’ and ‘explanted-STL’ was too significant for the best-fit algorithm, thus resulting in non-cooperative surfaces. One additional fossa could not be analyzed for volumetric wear because the software was unable to provide a ‘best fit’ between both explanted fossa and their ‘design-STL’, within the margin of error. As a result, a reliable volumetric wear volume could not be determined.Both the non-coated and coated Ti6Al4V condylar surfaces were evaluated using a 3D scanner (ATOS CORE 135, GOM GmbH, Braunschweig, Germany) to determine the linear wear of the condylar articulating surface, in similar fashion to the UHMWPE fossa part.Fig. 3: Macroscopic images of explanted fossa components of sheep #4473, with additional damage, having occurred during the explantation. This severe additional damage, occurred during retrieval, no longer allowed for reliable overlapping with the ‘design’-STL. No linear, or volumetric wear could be analyzed of this fossa. (A) Posterior view. Blue arro damage to posterior UHMWPE ridge. Black arro damage to titanium part. Red arro damage to titanium extension for fixation onto the zygomatic arch. (B) Lateral view. Blue arro damage to posterior UHMWPE ridge. Red arro damage to titanium extension for fixation onto the zygomatic arch. (C) Inferior view. Blue arro damage to posterior UHMWPE ridge. Black arro scalpel-reduced nonarticulating UHMWPE. Green arro worn out UHMWPE due to articulating with the condylar surface. Orange arro anteriorly worn out UHMWPE volume due to contact with the coronoid processNikolas de Meurechy NW.indd 141 05-06-2024 10:14