Dynamic compressive response of the human pelvis axial loading of the sacroiliac joint

The purpose of this study was to quantify the biomechanical response of the intact human pelvis subjected to dynamic axial compressive loading. Axial compression tests were performed on a total of six fresh frozen human cadaver pelves, five male and one female. The intact pelves were fixed to a load cell with a custom aluminum pot placed around the sacrum. Special care was taken when potting the pelves in order to ensure that the orientation of the pelves was representative of that seen in normal upright seating. The pelves were then subjected to dynamic compressive loading at a rate of approximately 2 m/s using a servo-hydraulic Material Testing System (MTS). The average peak force, moment, and displacement at the point of failure were 5,896 +/- 1455 N, 33.4 +/- 28.6 N-m, and 6.4 +/- 0.7 mm, respectively. The failure of the all pelvis specimens corresponded to a bilateral dislocation of the sacroiliac joint. As a general trend, strain gage data showed that the right and left superior ramus were placed in tension and the right and left ischium were placed in compression. The peak strain values ranged from 746 mstr to 5717 mstr in tension and from -356 mstr to -2677 mstr in compression. The current study will help future researchers reduce the number of incidences and severity of pelvic fractures that can result from falls from heights, ejection seat loading, or motor vehicle crash environments by providing valuable test data that quantifies biomechanical response of the human pelvis in vertical loading.