20-year experience of biomet stock alloplastic temporomandibular joint replacement in Chinese patients after technical modifications: a single-center retrospective study.

OBJECTIVES: To evaluate the clinical and radiographic outcomes of the Biomet stock alloplastic temporomandibular joint replacement (ATJR) after seven progressive surgical modifications in Chinese patients at a single center. MATERIALS AND METHODS: Patients who underwent ATJR from 2005 to 2025 were retrospectively reviewed. Seven surgical modifications were progressively introduced to optimize outcomes. Maximum interincisal opening (MIO), visual analogue scale (VAS) for pain, dietary function and mandibular mobility, and quality of life (QoL) were compared between baseline and final follow-up of at least 12 months. Postoperative computed tomography (CT) was used to evaluate prosthesis stability, screw position and heterotopic ossification (HO). Complications, revision rates, and Kaplan-Meier prosthesis survival rate were analyzed. RESULTS: 300 patients with 392 prostheses were included in the study. After a mean follow-up of 67.4±43.5 (12-208) months, MIO improved significantly from 23.7±13.5 mm to 34.2±6.9 mm (p < 0.001). QoL improved by 36.6% and VAS scores improved by 63.8-76.3%. 222 patients with 289 prostheses had CT follow-up exams 12-183 months after surgery (mean 40.9±33.7). HO of varying degrees was observed in 116 prostheses (40.1%) and screw loosening occurred in 7 prostheses (2.4%). 12 prostheses were revised (3.1%) including infection, persistent discomfort, screw loosening or severe HO. Cumulative prosthesis survival rates were 99.1%, 98.1%, 96.9%, and 94.7% at 1, 3, 5 and 10 years, respectively. CONCLUSIONS: Biomet stock ATJR has satisfactory results in Chinese patients with surgical modifications. CLINICAL RELEVANCE: Long-term follow-up of Biomet stock ATJR in Chinese patients showed satisfactory clinical, radiological and survival rates with surgical modifications, supporting its broader application in populations with anatomical features distinct from those of Western patients.