Page 353 - Demo

General discussion 35113was successful, as a proper integration of the ramal component was seen in both the radiological analysis, as well as the histological analysis of the two ramal samples, showing bone formation within the lattice structure.(109)However, for proper osseous integration of the LPM enthesis, several other requirements must be met as well. Firstly, the enthesis needs to be in direct contact with the condylar scaffold. As stated earlier, several intraoperative difficulties were encountered, hindering proper fixation onto the scaffold. Furthermore, once fixated, proper stability is needed for osseous integration to occur. Micromotions between an implant and the adjacent bone should not only be limited to 28µm in order to promote osteogenesis, but in case of the occurrence of repetitive micromotions of 150µm or more, formation of fibrous tissue between the implant and adjacent bone can be seen.(110–113) In absence of this stability, successful osseointegration between the implant and its boney contact surface will be severely limited, leading to the formation of a soft tissue connection. Because the fixation of the LPM is limited to the use of a polydioxanone (PDS) suture, in addition to the sheep being highly dependent on the LPM during chewing and rumination, it is very likely that an insufficient amount of stability between the LPM and scaffold was obtained in our experiment. Sufficient MSC, osteoblasts and osteocytes need to be present at the implant site. However, when performing the condylectomy, the periosteum is removed. This can have an additional negative effect, as the periosteal inner layer, containing osteogenic progenitor cells, has significant osteoblastic potential.(114,115) In case of absence of the periosteum, these progenitor cells can be derived directly from the Haversian canals, as is the case for the ramal and fossa component. However, this contact repair can only occur in case of direct contact between the implant and when micromotions between the implant and adjacent bone are limited to 28µm.(110–113,116) While a local increase in osteoblasts and osteocytes was attempted by grinding down the resected condyles and applying this bone into the scaffold, mixed with a fibrin sealant, no MSC were applied, thus limiting the possibility of osteogenesis as well.Nikolas de Meurechy NW.indd 351 13-06-2024 11:30