Dynamic imaging and wrist biomechanics: a narrative review

Area of Science:

• Orthopedics
• Biomechanics
• Radiology

Background:

• The wrist's complex, coupled intercarpal kinematics are challenging to interpret clinically.
• Traditional wrist models are often static, failing to capture dynamic biomechanical interactions.
• Current limitations lead to under-recognition of clinically relevant wrist instability.

Purpose of the Study:

• To review dynamic imaging studies of wrist kinematics over the past 10-15 years.
• To evaluate four modalities (4D-CT, biplanar videoradiography, 4D MRI, motion capture) for kinematic assessment.
• To understand the clinical utility of dynamic imaging in diagnosing wrist instability.

Main Methods:

• Narrative review of in vivo dynamic imaging studies.
• Focus on quantitative kinematic outcomes.
• Evaluation of 4D-CT, biplanar videoradiography, 4D MRI, and motion capture.

Main Results:

• Wrist kinematics are dependent on motion phase, loading, and task.
• Instability signs like scapholunate instability may only appear under specific conditions.
• 4D-CT and biplanar videoradiography offer valuable in vivo kinematic assessment, each with unique strengths.

Conclusions:

• Dynamic imaging highlights abnormal motion patterns as the cause of wrist instability.
• Modalities provide complementary, structure-specific insights for clinical interpretation.
• Standardized protocols and validated thresholds are needed for widespread clinical adoption.