The indirect effect of temporomandibular kinesiophobia on the association between limited mouth opening symptoms and maximum mouth opening in postoperative oral cancer patients: a mediation analysis.

BACKGROUND: Limited mouth opening is a prevalent complication among oral cancer patients, greatly impairing their physical and mental health as well as overall quality of life. Although the physiological mechanisms of mouth-opening dysfunction have been partially clarified, the potential role of psychological factors such as kinesiophobia remains understudied. Based on the fear-avoidance model, this study aimed to explore the correlations among limited mouth opening symptoms, maximal interincisal opening (MIO), and temporomandibular kinesiophobia in postoperative oral cancer patients, and to further investigate the indirect effect of temporomandibular kinesiophobia between limited mouth opening symptoms and MIO. METHODS: This cross-sectional study recruited 305 patients with oral cancer in Hunan, China, from April to June 2025. All participants completed assessments at one month after surgery. Maximal Incisal Opening (MIO), the Gothenburg Trismus Questionnaire (GTQ), and the Tampa Scale for Kinesiophobia for Temporomandibular Disorders (TSK-TMD) were used for data collection. Correlations among the three variables were analyzed, and the indirect effect of mandibular kinesiophobia was further explored. RESULTS: Correlations were observed among the Gothenburg Trismus Questionnaire (GTQ), the Tampa Scale of Kinesiophobia for Temporomandibular Disorders (TSK-TMD), and the MIO scores. MIO was negatively correlated with GTQ (r = - 0.696, p < 0.01) and TSK-TMD (r = - 0.517, p < 0.01), while GTQ and TSK-TMD were positively correlated (r = 0.471, p < 0.01). Mediation analysis revealed that temporomandibular kinesiophobia showed an indirect effect in the association between GTQ-derived limited mouth opening symptoms and MIO (β = - 0.077, 95% CI = - 0.112 to - 0.047). This indirect effect accounted for 16.52% of the total effect. CONCLUSION: This cross-sectional study examined the interrelationships among maximal interincisal opening, limited mouth opening symptoms, and temporomandibular kinesiophobia in postoperative oral cancer patients. Correlations existed among the three variables, and temporomandibular kinesiophobia showed an indirect effect on the association between limited mouth opening symptoms and maximal interincisal opening. These findings suggest that assessment of mandibular kinesiophobia may be a useful component of rehabilitation for patients with limited mouth opening.