Evaluation of Temporomandibular Disorders in Contralateral Joint after Unilateral Interpositional Gap Arthroplasty for Temporomandibular Joint Ankylosis

Abstract

Interpositional gap arthroplasty is the standard treatment for temporomandibular joint (TMJ) ankylosis. There are fewer studies evaluating the contralateral normal TMJ in case of a unilateral TMJ ankylosis after the release. We hypothesised that temporomandibular disorders (TMD) of some degree will appear in the contralateral normal joint due to uneven functional load. Twenty-two patients of unilateral TMJ ankylosis underwent interpositional gap arthroplasty by a single surgeon using a standard technique. The interpositional material used was autogenous pedicled buccal fat pad. They were evaluated clinically and radiologically for the development of TMDs in the contralateral normal TMJ. The clinical assessment was done using the Axis I tool of Diagnostic Criteria – Temporomandibular Disorders (DC-TMD) wherein the following parameters were assessed: (a) myalgia, (b) arthralgia, (c) degenerative joint disease, (d) disc displacements, (e) headaches attributed to TMD, and (f) subluxation. Radiographic assessment in terms of morphological changes in contralateral condyle was made between the pre- and post-operative CBCT. The Mimics 18.0 software package (Materialise, Leuven, Belgium) was used to create 3D reconstructions and to calculate change in volume of condyles. Discrete categorical data were represented in the form of either a number or a percentage. The normality of quantitative data was checked by measures of Kolmogorov-Smirov Tests of Normality. For comparison of normally time related variables, paired t test was applied. Median was calculated for extremes of data. The statistical analysis was carried out using SPSS statistics software (Version 22.0). Age range was 5-60 years; M:F was 11:11. Follow-up period ranged from 2 years to 12 years. At the longest follow-up, none of the patients developed TMD in the contralateral joint and only 1 patient developed subluxation of the normal condyle. There was significant improvement in lateral and contralateral excursions. No significant morphological changes were found in the contralateral condyle though there was an increase in contralateral condylar volume. We concluded that unilateral interpositional arthroplasty did not lead to contralateral TMD. There was significant improvement in lateral excursions following ankylosis release. There was increase in volume of the contralateral condyle after release of ankylosis. This may be attributed to functional adaptation of the joint.