Magnetic resonance imaging analysis of screw in-type lateral anchor pull-out in large to massive rotator cuff repair in patients older than 60 years

Background: This study was performed to identify the incidence of screw in-type lateral anchor pull-out in patients older than 60 years who underwent rotator cuff repair for large to massive rotator cuff tears.Methods: This study reviewed 25 patients older than 60 years who were diagnosed with large to massive rotator cuff tear and underwent arthroscopic rotator cuff repair in our hospital from March 2017 to February 2021. Preoperative tear size (anterior to posterior, medial to lateral) was measured via preoperative magnetic resonance imaging (MRI), and the re-tear rate was evaluated at 3 months via MRI. All 25 patients underwent MRI scanning on postoperative day 1 and at 3 months after surgery. The change of lateral row anchor position was measured in axial views on MRI images. The change of anchor position was measured postoperative day 1 and 3 months after surgery by MRI and statistically compared according to bone mineral density (BMD), sex, and number of lateral anchors. Results: Two consecutive MRIs (postoperative day 1 and 3 months) in 25 patients were compared. Anchor pull-out occurred in six patients during 3 months (6.7%), and the mean pull-out length difference was 1.56 mm (range, 0.16–2.58). There was no significant difference in the number of pull-out anchors, degree of pull-out difference, or the re-tear rate by comparing BMD (A, BMD≤-2.5; B, BMD>-2.5), sex, or number of anchors used in each surgery (C, two anchors; D, three anchors) (p>0.05). Conclusions: Pull-out of screw in-type lateral anchors was observed in very few patients (6.7%), and the mean pull-out length difference was negligibly small (1.56 mm) in our study. The screw in-type lateral anchor seems to be a decent option without concern of anchor pull-out even in elderly patients (>60 yr).