3D motion reliability of occipital condylar glide testing: From concept to kinematics evidence.

Background: To date, segmental data analyzing kinematics of occipital condylar testing or mobilization is lacking.

Objectives: The objective of this study was to assess occipitoatlantal 3D motion components and to analyze inter- and intra-rater reliability during in vitro condylar glide test.

Methods: To conduct this study, four fresh cadavers were included. Dissection was carried out to ensure technical clusters placement to skull, C1 and C2. During condylar glide test, bone motion data was computed using an optoelectronic system. The reliability of motion kinematics was assessed for three skilled practitioners performing two sessions of 3 trials on two days interval.

Findings: During testing, average absolute motion ROM (±SD) were up to 4.1 ± 2.1°, 0.7 ± 1.3° and 10.3 ± 2.5° for occipitoatlantal lateral bending, axial rotation and flexion-extension, respectively. For position variation, magnitudes were 2.3 ± 1.8 mm, 1.1 ± 1.3 mm and 2.6 ± 0.8 mm for anteroposterior, cephalocaudal and mediolateral displacements. Concerning motion reliability, variation ranged from 0.6° to 3.4° and from 0.3 mm to 1.6 mm for angular displacement and condyle position variation, respectively. In general, good to excellent agreement was observed (ICC ranging from 0.728 to 0.978) for the same operator, while consistency was limited to lateral/side bending and lateral condyle displacement between operators, with respective ICCs of 0.800 and 0.955.

Conclusions: This study shows specific motion patterns involving extension and lateral bending of the occipitoatlantal level for anterior condylar glide test. In addition, condyle position variation demonstrated coupled components in forward and heterolateral directions. However, task seems not to be side specific. In general, reliability of 3D motion components showed good intra-operator agreement and limited inter-operator agreement.