A Method for Quantifying Condylar Motion in Patients With Osteoarthritis Using an Electromagnetic Tracking Device and Computed Tomography Imaging

Purpose: The purpose of this study was to develop a method to accurately study the kinematic changes of the temporomandibular joint (TMJ) in patients treated with hemijoint implant reconstruction for dysfunction of advanced degenerative osteoarthritis. Materials and Methods: Mandibular kinematic motion data and patient-specific computed tomography (CT) data were acquired. Patients were fitted with custom dental stents that were embedded with metal markers to link the mandibular kinematics data with the 3-dimensional TMJ CT images. An electromagnetic tracking device was used to collect kinematic motion data during maximal mouth opening and closing. The coordinate systems of the kinematic data and CT data were registered to calculate the motion of the mandibular condyle. Results: This technique was successfully used to study patients with motion aberration of the TMJ due to osteoarthritis. A typical case is illustrated in which the motion of both mandibular condyles was simulated preoperatively and postoperatively. Conclusions: The results of this study suggest that it is possible to use the proposed methodology to accurately quantify the motion of the mandibular condyle in 3 dimensions. The developed technique is user-friendly and noninvasive to the patient. The proposed methodology is a potential clinical tool that may be used in the management of patients with TMJ dysfunction.