A novel method for in-vivo evaluation of finger kinematics including definition of healthy motion patterns

• New methodology was used in order to collect data on each and every finger segment.
• Four different movements were performed.
• Intra- and inter-finger joints synergies can be appreciated.
• Good intra-/inter-operator reproducibility and soft tissue artefact quantification
• Reference database of healthy sample was created for further clinical investigation.

BackgroundDespite recent progress in motion capture technology, such as stereophotogrammetry based on the tracking of markers set on the subject, it remains challenging to develop a complete protocol for in-vivo functional evaluation of the hand. The current practical problems regarding small anatomical segments, such as the fingers, are mainly due to the high concentration of markers in a relatively reduced volume.MethodsThis paper proposes a novel procedure for hand functional analysis by analysing finger behaviour along the main displacement plane simultaneously with combined motions. The objective was two-fold. For one thing, a novel data collection protocol was implemented, which includes specific setting of the motion capture system and the development of finger marker clusters. The second purpose of this study was to create a reference database of a healthy sample for further clinical investigation. Twenty healthy volunteers took part in the study. Analytical motions (flexion/extension and abduction/adduction) of all five fingers were recorded.FindingsResults showed good correspondence with the literature. Specific kinematic behaviour of each analysed joint is reported. Statistically significant differences were found between the right and left sides of the subjects for the flexion/extension movement only, between the finger joints and between the fingers for all movements. No significant difference was found between genders. A validation protocol was performed, which proved the validity of the presented methodology.InterpretationThe protocol appears suitable for further use in motion analysis and for musculoskeletal modelling of the hand. It will also be considered for clinical application.