Bone Cement Improves Suture Anchor Fixation

Abstract

Suture anchor fixation failure can occur if the anchor pulls out of bone. We hypothesized that suture anchor fixation can be augmented with polymethylmethacrylate cement, and that polymethylmethacrylate can be used to improve fixation in a stripped anchor hole. Six matched cadaveric proximal humeri were used. On one side, suture anchors were placed and loaded to failure using a ramped cyclic loading protocol. The stripped anchor holes then were injected with approximately 1 cc polymethylmethacrylate, and anchors were replaced and tested again. In the contralateral humerus, polymethylmethacrylate was injected into anchor holes before anchor placement and testing. In unstripped anchors, polymethylmethacrylate increased the number of cycles to failure by 34% and failure load by 71% compared with anchors not augmented with polymethylmethacrylate. Polymethylmethacrylate haugmentation of stripped anchors increased the cycles to failure by 31% and failure load by 111% compared with unstripped uncemented anchors. No difference was found in cycles to failure or failure load between cemented stripped anchors and cemented unstripped anchors. Polymethylmethacrylate can be used to augment fixation, reducing the risk of anchor pull-out failure, regardless whether the suture anchor hole is stripped or unstripped.