Functional thumb carpometacarpal joint motion during activities of daily living: A three-dimensional kinematic analysis.

Abstract

Background: Task-specific three-dimensional data describing thumb carpometacarpal (CMC)-related kinematics during activities of daily living remain limited.

Purpose: To describe thumb CMC-related kinematics during standardized functional tasks in healthy young adults using high-frequency magnetic tracking.

Study design: Cross-sectional descriptive study.

Methods: In 11 healthy young adults, thumb CMC-related motion was recorded during 11 standardized tasks corresponding to the hand-function domain of the Thumb Disability Exam. Radial-ulnar motion, palmar-dorsal motion, and opposition-related axial rotation were summarized within each participant for each task and axis, and task-specific descriptive values were calculated across participant-level summaries.

Results: The functional tasks demonstrated distinct kinematic profiles. Tasks involving manipulation, rotation, or bimanual object handling, including using a knife, opening a jar, buttoning a shirt/blouse, tying shoelaces, and wringing a dishcloth/washcloth, showed larger angular excursions than tasks involving more static holding or precision positioning. Descriptive heat maps showed commonly observed angular regions within the processed dataset, but these patterns were interpreted descriptively because the time-series samples were not independent participant-level observations.

Conclusions: This study provides preliminary descriptive data on three-dimensional thumb CMC-related kinematics during standardized activities of daily living in healthy young adults. The findings suggest that thumb motion requirements differ across functional tasks. Further validation in larger, older, and clinical populations is required before these data can be applied to orthotic design, surgical planning, or rehabilitation goal setting.

Clinical relevance: These preliminary findings describe task-specific thumb CMC-related motion during activities of daily living and may contribute to future research on thumb biomechanics, functional assessment, and clinical intervention planning after further validation.

Level of evidence: Diagnostic Level III.