Does simultaneous alloplastic temporomandibular joint reconstruction affect the accuracy of Le Fort I osteotomy?

Simultaneous alloplastic temporomandibular joint reconstruction (ATMJR) with Le Fort I osteotomy (LFI) may be indicated when significant temporomandibular joint (TMJ) pathology accompanies dentofacial deformities. Currently, the impact of concomitant ATMJR on LFI accuracy is not known. The purpose of this study was to assess the influence of patient-fitted ATMJR on the accuracy of simultaneous LFI. In this retrospective cohort study, patients undergoing LFI with and without ATMJR were enrolled. Preoperative and postoperative cone-beam computed tomography was analyzed using regional voxel-based registration. The primary predictor variable was use of ATMJR, and others included impaction at the maxillary central incisor (U1), age, and sex. The primary outcome variable was the mediolateral/superoinferior/anteroposterior absolute linear surgical error at U1 (U1AE). The secondary outcome variable was the three-dimensional surgical error at U1. In 20 subjects (eight ATMJR, 12 non-ATMJR), median U1AE ranged from 0.50 to 1.30 mm and median three-dimensional surgical error from 1.37 to 2.17 mm. ATMJR was associated with higher anteroposterior U1AE (median difference 0.8 mm, P = 0.012) and under-impaction (mean 0.86 mm, P = 0.036). Simultaneous ATMJR is associated with greater anteroposterior surgical error and a tendency towards under-impaction. Appropriate case selection and planning modifications should be considered as appropriate.