The role of the lateral pterygoid muscle in the sagittal fracture of mandibular condyle (SFMC) healing process

The aim of this study was to examine the role of the lateral peterygoid muscle in the reconstruction of the shape of the condyle during healing of a sagittal fracture of the mandibular condyle. Twenty adult sheep were divided into 2 groups: all had a unilateral operation on the right side when the anterior and posterior attachments of the discs were cut, and an oblique vertical osteotomy was made from the lateral pole of the condyle to the medial side of the condylar neck. Ten sheep had the lateral pterygoid muscle cut, and the other 10 sheep did not. Sheep were killed at 4 weeks (n = 2 from each group), 12 weeks (n = 4), and 24 weeks (n = 4) postoperatively. Computed tomograms (CT) were taken before and after operations. We dissected the joints, and recorded with the naked eye the shape, degree of erosion, and amount of calcification of the temporomandibular joint (TMJ). In the group in which the lateral peterygoid muscle had not been cut the joints showed overgrowth of new bone and more advanced ankylosis. Our results show that the lateral pterygoid muscle plays an important part in reconstructing the shape of the condyle during the healing of a sagittal fracture of the mandibular condyle, and combined with the dislocated and damaged disc is an important factor in the aetiology of traumatic ankylosis of the TMJ.