THE RELATIONSHIP OF SUTURE ANCHOR FAILURE AND BONE-DENSITY TO PROXIMAL HUMERUS LOCATION - A CADAVERIC STUDY

The purpose of this study was to evaluate spatial variations in the pu llout strength of a suture anchor in the proximal humerus, and to corr elate any differences with the local bone mineral density (BMD). Screw -type suture anchors threaded with wire sutures were inserted at six d ifferent anchor insertion sites in 11 human cadaveric humeri (average age, 80 years), Load to failure tests with forces applied in line with the axis of insertion were performed, and bone mineral density measur ements were then made at these sites. The greater tuberosity showed an terior and posterior differences in anchor pullout force (P =.03), wit h the posterior portion showing higher strength (154 N) than the anter ior area (96 N). Neither the lesser tuberosity (185 N anterior area an d 177 N posterior area) nor the humeral neck (170 N anterior area and 174 N posterior area) showed significant differences? and they were st atistically equivalent to the greater tuberosity. There was no demonst rable difference in BMD at any of the six sites tested. There is no su pport for the hypothesis that significant differences in load to failu re exist among the lesser tuberosity, humeral neck, and greater tubero sity. Also, there is no support for the hypothesis that the load to fa ilure variations for the proximal humerus are dependent on BMD. Bone m ineral density appears to have no correlation with the pullout strengt h of a screw-type suture anchor.