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Chapter 8226protrusive function in patients with a restored LPM. However, their study was not supported by any radiographical, histological or kinematic results. Furthermore, no information was provided as to which component of the LPM was reinserted onto the mandibular stump is unclear.(29) This is of importance, as a distinction between two different types of enthesis, the fibrous and the fibrocartilaginous enthesis, can be made. The first consist of dense fibrous connective tissue with mineralized collagen fibers connecting to the periosteum or directly inserting into the bone, whereas the latter contains four zones, with increasing amounts of calcified tissues to transition into bone, allowing for a strong insertion and the force that is generated to be transitioned to the bone.(15,30,31) The entheses found in masticatory muscles are unique as they boast both types of entheses.(15,30,32) This is also the case for the lateral pterygoid muscles’ insertion. The LPM enthesis transitions from a fibrocartilaginous one immediately below the attachment of the mandibular joint capsule to a fibrous one more caudally, which first inserts directly into the bone and below that with the periosteum. (15,30,32) Whilst the fibrous enthesis is less prone to injury, both the MTJ and BTJ in the fibrocartilaginous enthesis are highly specialized tissues, with only limited healing capacities. Notably, after injury of either the BTJ or MTJ, scar tissue formation often occurs, leading to both a decreased function and an increased risk of recurrent injury.(14,15) While research into enthesis healing and reconstruction is currently very active, pursuing several different approaches (mesenchymal stem cells, growth factors,…) results for broad clinical application remain scarce at this point.(14,15) Therefor, the surgery protocol was devised in such a fashion that the risk of the tendon failing at either of these levels was overcome by not only preserving the enthesis as a whole, but also dissection part of the adjacent bone. In addition to preserving the enthesis’ integrity, we hypothesized this could allow for osseointegration onto and into the TMJR, providing further long-term stability to the LPM reinsertion. However, to allow for proper osseointegration, several important factors come into play.Nikolas de Meurechy NW.indd 226 05-06-2024 10:14