Joint Loading of the Thumb While Operating a Mechnical Pipette – an Inverse Dynamic Analysis

INTRODUCTION Thumb-push manual pipettes are commonly used tools in many medical, biological, and chemical laboratories. Epidemiological studies [1] indicate that the use of pipettes is strongly associated with musculoskeletal disorders (MSDs) in the hand and shoulder. Almost 90% of pipette users, who continuously used the pipettes for more than an hour on a daily basis, reported hand and/or elbow disorders [2]. Despite the strong evidence that operation of the thumb-push manual pipette is related to MSDs in the thumb, the biomechanics of the thumb during pipetting have not been quantified. It is not known if the operation of the thumb-push pipette would induce excessive joint torque in the CMC joint, a factor that may potentially cause degeneration of the articulation [3]. The purpose of the current study was to analyze the kinematics and loading in the joints of the thumb during pipetting.