Cervical kinematics estimated by finite helical axis behaviour differs in patients with neck related problems as compared to healthy controls.

Purpose The present study analyses the kinematics of patients with neck problems and healthy controls by estimation of Finite Helical Axis behaviour. A cross sectional study design was used to investigate whether FHA behaviour differs due to neck problems.
Methods: 584 subjects were recruited from private and ambulatory institutional physiotherapy practices. Among these 171 patients with neck related problems were selected based on referral diagnosis by primary care general practitioners. Cervical kinematics were compared based on minimal convex hull, path length and mean angle of the Finite Helical Axis distribution as well as on the helical angle. Three active planar motions were registered: flexion-extension, axial rotation and lateral bending.
Results: Patients demonstrated a significantly reduced and less variable behaviour of the Finite Helical Axis during active flexion-extension and axial rotation motions as compared to healthy individuals and lateral bending.
Conclusion: Patients with neck related problems demonstrate a more restricted motion behaviour with less variability in Finite Helical Axis distribution and orientation during active planar motions. At present it is not clear whether these kinematic differences are the result or the cause of dysfunction. These slides can be retrieved under Electronic Supplementary Material.