Sternal Displacement During Activities

Purpose: The purpose of this study was to determine whether sternal displacement occurs, decreases over time, and varies with adherence to sternal precautions during functional activities after median sternotomy. Methods: Seventeen subjects had ultrasound images taken at two and then six to eight weeks after median sternotomy to measure the sternal gap and displacement during five activities commonly limited by sternal precautions. The subjects were divided into two groups based on self-reported compliance with sternal precautions. Results: At the upper sternal site, displacement occurred with all activities in both sessions and decreased over time. At the lower sternal site, displacement only occurred during dynamic activities and decreased over time. Subjects who fully complied with sternal precautions had less upper sternal displacement during stand-to-sit (P = .043; ES = −1.076) and trend toward reduced displacement during sit-to-stand and horizontal abduction with large effect sizes, −.893 and −.975, respectively. Conclusion: Sternal displacement may vary with the task performed and between sternal sites. Reduced sternal displacement identified over time indicates sternal healing. Pectoralis major tension seems to be a primary mechanism of sternal displacement during common functional activities. Our findings suggest that full compliance with sternal precautions may promote sternal healing.