Dynamic imaging and wrist biomechanics: a narrative review.

INTRODUCTION

The wrist is a complex joint with tightly coupled intercarpal kinematics that remain difficult to interpret clinically. Traditional models, derived from static imaging and cadaveric studies, treat the wrist as a three-dimensional structure. However, wrist biomechanics is inherently dynamic, emerging from interactions across motion phases, loading conditions and functional tasks. Current limitations contribute to under-recognition of clinically relevant instability.

METHODS

This narrative review summarizes representative studies from the past 10-15 years, with emphasis on in vivo dynamic imaging studies reporting quantitative kinematic outcomes. Four modalities (4D-CT, biplanar videoradiography, four-dimensional magnetic resonance imaging and motion capture) were evaluated in terms of kinematic findings and clinical utility, with findings organized by substructure.

RESULTS

Dynamic imaging demonstrates that wrist kinematics are phase-, load- and task-dependent. Abnormalities such as scapholunate instability may only become apparent during specific phases of motion or under physiological loading. 4D-CT currently provides the most accessible in vivo assessment of intercarpal coordination, while biplanar videoradiography offers high-precision kinematic analysis in controlled settings. Motion capture characterizes task-dependent wrist motion for functional activities but lacks intercarpal resolution, whereas four-dimensional magnetic resonance imaging offers potential for integrating soft-tissue behaviour, although current applications remain limited.

CONCLUSION

Dynamic imaging shows that wrist instability arises from abnormal motion patterns rather than a static structural abnormality. Rather than competing, these modalities provide complementary, structure-specific insights. This framework supports clinical interpretation of wrist instability and guides appropriate technique selection. However, clinical interpretation will require further standardized protocols and clinically validated thresholds.