Biomet stock temporomandibular joint prosthesis: Long-term outcomes of the use of titanium condyles secured with four or five condylar fixation screws.

PURPOSE: The aim of this study was to determine the long-term outcomes following TMJ replacement using the stock Zimmer-Biomet TMJ device. In particular, investigated whether the titanium condylar implant and number of screws used to fixate it to the mandibular ramus had any impact on outcomes.

METHODS: Subjects who underwent surgical implantation of a stock Zimmer-Biomet TMJ prosthesis were identified for this retrospective study. All patients received a titanium condylar component secured with four or five screws and ultra-high molecular weight polyethylene (UHMWPE) fossa with no metal reinforcement. Pre- and postoperative pain scores (VAS) and maximum interincisal opening (MIO) data were collected. Additional data included patient demographics, as well as operative, postoperative and follow-up details. Data were analysed with IBM SPSS 2.0 through the use of paired t-tests, and ANOVA and ANCOVA analysis.

RESULTS: 190 subjects were identified. Following exclusions, the remaining study population (n = 60) consisted of 58 females and two males with a mean age of 53.5 years at time of surgery. Preoperative VAS and MIO values were 6.08 (SD = 2.24) and 31.88 mm (SD = 7.38 mm), respectively. 90% of the cohort required four screws to fix the prosthetic condylar component in place. After a median follow up of 5.2 years (95% CI: 4.73-5.62 years), with a range of 2-9 years, the VAS was 0.91 (SD = 1.89; p < 0.001) and the MIO was 34.8 mm (SD = X; p = 0.015). Only one device failed over the 9-year study period.

CONCLUSION: The results of this study demonstrate good VAS and MIO outcomes following the implantation of a stock Zimmer-Biomet TMJ device. Additionally, good long-term outcomes were obtained with a titanium condylar component, fixed to the mandibular ramus with only four or five screws, and a UHMWPE fossa with no metal reinforcement.