Biomechanics of the sternoclavicular joint: an experimental and computational study.

BACKGROUND

This study aims to thoroughly investigate the biomechanics of the sternoclavicular joint (SCJ), a key component of the shoulder complex.

METHODS

Inertial sensors were used on live human subjects to measure joint movements during abduction-adduction, flexion-extension, and shrugging. These motion data were then applied to a musculoskeletal model (OpenSim) to analyze the SCJ's range of motion and joint forces. The model was validated using previously published data involving transcortical pins for motion tracking and results from instrumented shoulder prostheses for kinetic comparison.

RESULTS

Findings highlighted the SCJ's range of motion: at least 25° of elevation and 35° of retraction, with peak forces reaching 75% of body weight. The model has been validated against experimental results, and on the whole, it was found to provide reliable biomechanical information concerning clavicle elevation and SCJ forces; the estimation of clavicle retraction has resulted to be more critical: here, the use of inertial measurement units may produce an underestimation of angular displacements due to skin motion relative to the underlying bones, necessitating more invasive approaches.

CONCLUSION

Overall, the study provides insights into SCJ biomechanics and suggests a validated methodology for further analyses.