Kinematic Study of the Temporomandibular Joint in Normal Subjects and Patients Following Unilateral Temporomandibular Joint Arthrotomy With Metal Fossa-Eminence Partial Joint Replacement

Purpose: The primary purpose of this study is to quantify the kinematics of the temporomandibular joint (TMJ) in patients following unilateral TMJ arthrotomy with metal fossa-eminence partial joint replacement and compare them with TMJ kinematics of healthy individuals. Materials and Methods: Fourteen healthy volunteers and 13 female surgical patients (minimum 4 years postoperative) participated in this study. An electromagnetic tracking device was used to record the kinematics of the mandible relative to temporal bone during opening-closing, protrusive, and lateral movements. The mean linear distance (LD) traveled by condyles was compared between operated and normal subjects. Results: Patients responded with statistically significant improvement in pain and jaw function questions. Mean satisfaction with the surgical result was 25.7 on a scale of 1 to 30. The LD measured for condyles during all 4 movements showed similar measurements. However, operated and unoperated condyles showed statistically significant motion values during opening and protrusive motion from each other and from normal subjects. In addition, contralateral condyles during lateral motion showed statistically significant values in operated, unoperated, and normal condyles. Conclusion: The results of this study suggest that the surgical reconstruction of the TMJ with partial joint replacement provided highly significant clinical improvement. Moreover, condyle and incisor kinematics were preserved to a significant amount as compared with the normal group. The difference in kinematic measurements between the operated and unoperated condyle was significant and secondary to previous joint disease and previous surgical intervention. These results should be evaluated by prospective studies in pre- and postsurgical patients.