Abstract

--- - This study aimed to characterize samples from patients diagnosed with TMJ ankylosis, using both clinical and histological data. - Both clinical and histological analyses of retrieved tissue samples from patients with primary TMJ ankyloses were performed retrospectively (1980-2012). All patients had been subjected to primary arthroplasty. Our study analyzed connective tissue differentiation, ossification patterns, and bone resorption, using histology and immunohistochemistry. - Fifteen case records, with a sex ratio of 4:1 (men:woman) and a median age of 8 years, were collected. Six patient samples reported a previous inflammatory event. Histologically, 15 samples exhibited fibrous tissue. Among these, 13 displayed bone at different stages of maturity (fibrous/bony ankylosis). Eleven samples showed aberrant cartilage, characterized by hypertrophic chondrocyte-like cells at the bone/ cartilage interface. Four samples revealed inflammatory infiltrate; in one case, this was organized as a lymphoid follicle. Eleven samples showed bone resorption by attached osteoclasts. Interestingly, nonattached osteoclasts were detected, suggesting locally impaired bone remodeling. An association between the presence of mature/lamellar bone and the presence of osteoclasts was observed (p = 0.03). No association was found between previous history of either trauma or infection and the histological type of ankylosis (p = 0.74). There was no association between the histological presence of inflammation or infection and the type of ankylosis (p = 0.63 and p = 0.87, respectively). - Retrieved TMJ ankylosis tissues displayed both aberrant ossification and reduced focal bone resorption, suggesting a dysregulated healing response. (C) 2021 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.