Slight Reduction in the Insertion Depth for an All-Suture Anchor Decreases Cyclic Displacement in the Shoulder Glenoid

Purpose: To determine if the depth of anchor insertion affects the biomechanical performance of a 1.5-mm all-suture anchor in glenoid bone.

Methods: A 1.5-mm all-suture anchor was tested in 8 matched pairs of human cadaver fresh-frozen glenoids. Anchors were inserted at 6 different locations and tested at 3 different depths: 21 mm (preset drilling depth), 17 mm, and 13 mm. Cyclic loading and destructive testing was performed. Displacement after 100 and 200 cycles, along with ultimate failure strength, was determined.

Results: After 100 and 200 cycles, anchors placed at 13 and 17 mm had undergone significantly less displacement than those at 21 mm (P < .05). No difference was observed in ultimate load to failure between anchors placed at 21 and 17 mm. However, the ultimate load to failure was significantly lower in anchors placed at 13 mm (P < .05). There were 5 clinical failures in anchors placed at 21 mm, one at 17 mm, and none at 13 mm.

Conclusions: The 1.5-mm all-suture anchor tested in this study has an optimal insertion depth of 17 mm, 4 mm shallower than the preset drill depth. At the optimal insertion depth of 17 mm, it underwent significantly less displacement after cyclic loading without a reduction in the ultimate load to failure.

Clinical Relevance: Given the results of this study, the optimal insertion depth for this 1.5-mm all-suture anchor is 17 mm, 4 mm shallower than the preset drill depth.