Increasing pullout strength of suture anchors in osteoporotic bone using augmentation-A cadaver study

- Bone anchor interface seems to be a clinical problem in elderly patients.
- We suggest a cement augmentation of screw anchors for rotator cuff repair.
- We found a significant improvement of pullout forces of augmented anchors in comparison to conventional anchors.
- The results of this biomechanical study might improve clinical results of rotator cuff repair in elder patients.

BackgroundRotator cuff tears are of increasing clinical impact in the physically active elderly patients. Recent research revealed, that a high percentage of these patients present with significant loss of bone mineral density at the insertion site of the rotator cuff, thereby compromising suture anchorage for operative repair. We therefore hypothesized that augmentation of suture anchors improves biomechanical properties in low bone quality.Methods28 osteoporotic humeral heads were included in this biomechanical study. Bone quality at the anchor insertion sites (group 1: posterior-medial; group 2: anterior-lateral) within the greater tuberosity was analyzed using HR-pQCT (voxel size: 82 μm). Anchor positions of identical quality were then randomized to either conventional screw anchorage or polymethylmethacrylat augmented screw anchorage. All anchors were cyclically ramp-loaded until pullout.FindingsPullout strength accounted for 226 N in group I for conventional anchorage and for 332 N in augmented technique. In group 2 (anterior-lateral) the pullout strength was 209 N (conventional) and 304 N (augmented). Pull-out strength of augmented screw anchors was significantly higher in both groups (p < 0.05).InterpretationCompared to conventional insertion techniques, the cement augmentation technique increases the pullout strength of suture anchors in low bone quality significantly. Cement augmentation could therefore be a helpful tool for improved suture anchor stability, especially in locations of low bone quality.