Kinematic assessment of the temporomandibular joint before and after partial metal fossa eminence replacement surgery: a prospective study

Abstract

Purpose: This study compared the functional kinematic outcome of the temporomandibular joint (TMJ) in patients with end-stage TMJ osteoarthritis before and after TMJ hemijoint replacement surgery.

Materials and methods: Fourteen patients (15 joints), with a mean age of 46.1 years, undergoing metal fossa eminence hemijoint replacement surgery, participated in this study. Each patient's jaw motion was recorded using an electromagnetic tracking device and patient-specific computed tomography images. A visual analog scale patient response questionnaire was used before and after the operation to assess the subjective outcome of the surgery.

Results: The mean linear distance (LD) traveled by the incisors increased significantly due to the surgical intervention, from 30.4 +/- 6.9 mm preoperatively to 35.5 +/- 5.3 mm postoperatively (P = .02). The LD of the operated condyle decreased from 14.1 +/- 5.7 mm to 11.4 +/- 6.2 mm, but this was not significant. The mean LD for the unoperated condyle remained similar (preoperative, 13.2 +/- 5.9 mm; postoperative, 13.3 +/- 6.5 mm). The total mandibular rotation increased significantly, from 19.3 +/- 4.9 degrees preoperatively to 24.8 +/- 3.9 postoperatively (P < .01).

Conclusions: Kinematic data support the functional efficiency of hemijoint replacement surgery, with benefits of increased maximal mouth opening, preservation of operated and unoperated condyle translation motion, and increased mandibular rotation.