Functional outcomes and masticatory muscle thickness changes following temporomandibular joint surgery: A prospective cohort study.

OBJECTIVE

To evaluate functional outcomes and changes in masticatory muscle thickness (MT) following surgical management of temporomandibular joint disorders (TMDs).

METHODS

This prospective cohort study included patients undergoing surgical treatment for unilateral TMDs at a German tertiary referral centre over a 10-year period. The primary predictor variable was surgical intervention (preoperative vs. postoperative status). Primary outcomes included mandibular function, pain intensity, and MT changes assessed using magnetic resonance imaging. Statistical significance was set at P ≤ 0.05.

RESULTS

The cohort comprised 61 patients (78.7% female; mean age, 40.9 ± 16.2 years [range, 15-74]). Osteoarthritis was the most common indication (59%), followed by posttraumatic joint disease (39.3%) and ankylosis (1.6%). Arthroplasty was performed in 63.9% of patients, total joint replacement in 32.8%, and arthroscopy with arthrocentesis in 3.3%. Postoperatively, 91.8% of patients reported improved mandibular function. Mean maximum mouth opening significantly increased to 36.4 ± 8.4 mm, with significant gains in lateral excursion (8.9 ± 4.3 mm ipsilaterally; 8.7 ± 4.1 mm contralaterally). Protrusion showed a non-significant increase (0.65 mm). MT decreased in 90.2% of patients. Pain scores declined from 6.2 ± 0.7 to 1.4 ± 0.5, with 85% reporting improvement. Overall patient satisfaction was 90%. No major complications were observed, except for one infection requiring prosthesis revision.

CONCLUSION

TMJ surgery is associated with significant improvements in function and pain. The observed reduction in MT may reflect postoperative adaptation following restoration of joint mechanics, although the underlying neuromuscular and biological mechanisms cannot be determined from the present data.