Three-dimensional assessment of temporomandibular joint changes following maxillomandibular advancement surgery: a five-year follow-up study

This study aimed to evaluate changes of the temporomandibular joint (TMJ) following maxillomandibular advancement surgery (MMA), long-term postoperative skeletal relapse, and progressive condylar resorption (PCR) development. Preoperative and postoperative cone beam computed tomography (2 weeks, 5 years) of 50 patients (33 female, 17 male; mean age 25.6 years) were assessed three-dimensionally. Compared to the preoperative state, the largest long-term changes of the TMJ were observed in the condyles: mean volume decrease of 9.94% for the right condyle and 8.35% for the left. Condylar volume changes contributed most to the changes in condylar height (effect size right/left, η2 = 0.71/0.72) and horizontal postoperative skeletal relapse (η2 = 0.22/0.20). In contrast, glenoid fossa and joint space changes were modest and unassociated with skeletal relapse. Five female patients (10%) showed signs of PCR, with a mean reduction in condylar volume of 32%, a significant loss of condylar height and skeletal relapse. In conclusion, at 5 years following MMA, mainly condylar volume changes were observed, which had the largest effect on long-term postoperative skeletal relapse when compared to glenoid fossa and joint space changes. PCR occurred in 10% of the patients and was related to a significant loss of condylar height and skeletal relapse.