How Do Custom Temporomandibular Joint Replacements Function After 30 Years of Service?

BACKGROUND: Temporomandibular joint (TMJ) custom total joint replacement (TMJR) is a common procedure. This study evaluates the function of these devices after 30 years of service. PURPOSE: This study measured therapeutic effect using TMJ pain, jaw function, diet, quality of life (QOL), maximum incisal opening (MIO), and revision rate, 30 years post-TMJR. STUDY DESIGN: This retrospective cohort study evaluated patients receiving TMJR at Baylor University Medical Center between 1989 and 1993. Inclusion criteria were TMJR implantation, minimum 30-year follow up, and patients contacted and responded. Exclusion criteria were patients deceased, lost to follow up, and refusal to participate. PREDICTOR VARIABLES: These included age, sex, prior Proplast/Teflon or silastic implants, and number of previous TMJ surgeries. PRIMARY OUTCOME VARIABLES: These included therapeutic effect using TMJ pain, jaw function, and diet (Likert scale); QOL (subjective); MIO (mm); and revision rate at 30-year post-TMJR. ANALYSIS: Age distribution used Shapiro-Wilk test, mean, and standard deviation. Ordinal variables used median (50th percentile) and interquartile range (IQR) (25th to 75th percentile). Postsurgery changes used nonparametric Wilcoxon signed-rank for paired measures and Mann-Whitney U and Kruskal-Wallis tests for between group measures. MIO used parametric paired t-test. P value 0.05 was considered significant. RESULTS: Of 88 potential patients, 31 subjects (35%) completed the study with 30 females (97%). The mean age was 38.0 years (SD 9.93). The median follow up was 32.5 years (IQR 32 to 34). Median pain improved 8 (IQR 6.6 to 8.5) to 2 (IQR 0 to 4) (P < .001), jaw function 7 (IQR 4.5 to 8.5) to 5 (IQR 3.5 to 6.5) (P = .02), diet 7 (IQR 5.5 to 8) to 3 (IQR 1-5) (P < .001), and MIO 24 mm (IQR 19.5 to 35.5) to 35 mm (IQR 30 to 36) (P = .002). QOL improved for 29 subjects (94%). Exposure to Proplast/Teflon or silastic implants or not, showed no statistical significance (P > .05). Greater number prior TMJ surgeries had poorer outcomes (P < .05) except for MIO. TMJR revision was required for 7 subjects (23%) and replacement for 3 (9%). CONCLUSION: The study findings suggest custom TMJRs continue to function with improvement for pain, jaw function, diet, MIO, and QOL at a median 32.5-year postimplantation, supporting the long-term survival and function for clinical application consideration in patients requiring TMJR.