Comparison of disc position stability and condylar bone remodeling between two open disc repositioning surgeries: a retrospective single-center cohort study

Open suturing (OSu) and Mini-screw Anchor (MsA) are two commonly used open disc repositioning surgeries for anterior disc displacement (ADD) of the temporomandibular joint (TMJ). This study assesses the differences in disc position stability (DPS) and condylar bone remodeling (CBR) between these two surgical procedures in a single center.A retrospective cohort study using magnetic resonance imaging (MRI) scans (preoperation, 1 week and 12 mo postoperation) of all patients who had open TMJ disc repositioning surgery from January 2016 to June 2021 at one center through two surgical techniques (OSu and MsA) was performed. The predictor variable was technique (OSu and MsA). Outcome variables were DPS and CBR. During follow-up, DPS was rated as good, acceptable and poor, and CBR was graded as improved, unchanged, and degenerated. Multivariate analysis was used to compare the DPS and CBR at 12 months after adjusting 5 factors including age, sex, Wilkes stage, preoperative bone status (normal, mild/moderate abnormal) and the degree of disc repositioning (normal, overcorrected, and posteriorly repositioned). Relative risk (RR) for DPS and CBR was calculated by multivariate logistic regression.385 patients with 583 joints were included in the study. MRIs at 12 months showed that 514 joints (93.5%) had good DPS, and 344 joints (62.5%) had improved CBR. Multivariate analysis revealed that OSu had higher DPS (RR=2.95; 95% confidence interval [CI], 1.27 to 6.85) and better CBR (RR=1.58; 95%CI, 1.02 to 2.46) than MsA. Among the factors affecting DPS, females had better results than males (RR=2.63; 95%CI, 1.11 to 6.26) and overcorrected or posteriorly repositioned discs were more stable than normally-repositioned discs (RR=5.84; 95%CI, 2.58 to 13.20). The improvement in CBR decreased with age increasing (RR=0.91; 95%CI, 0.89 to 0.93). Preoperative mild/moderate abnormal bone status had a higher probability of improved CBR compared to normal preoperative bone status (RR=2.60; 95%CI, 1.76 to 3.83).OSu had better DPS and CBR than MsA. Sex and the degree of disc repositioning impacted DPS, while age and preoperative bone status affected CBR.