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

Abstract

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 tear (RCT).

Methods: We reviewed 25 patients over 60 who were diagnosed with large to massive RCT 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). All 25 patients underwent MRI scanning on postoperative day 1 and at 3 months after surgery. The change of anchor position was measured in axial views on MRI images postoperative day 1 and 3 months after surgery. And it was statistically compared according to bone mineral density (BMD), sex, and number of lateral anchors.

Results: Two 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 mm). There was no significant difference in the number of pull-out anchors, degree of pull-out difference 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 anchors was rarely observed and the mean pull-out length difference was negligibly small 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.

Keywords: Magnetic resonance imaging; Pull-out; Rotator cuff; Lateral anchor.

Fig. 1.

Magnetic resonance imaging images on (A) postoperative day 1 and (B) 3 months after surgery with the same view (Outphase axial T2 IDEAL). The length of lateral row anchor pull-out was assessed by measuring the distance anchors pulled out perpendicular to the outer lateral cortex.

Fig. 2.

The greater tuberosity (GT) can be divided into three portions of anterior (Ant), middle (Mid), and posterior (Post). In our study, a total of six patients demonstrated anchor pull-out. The mean age of these patients was 67.17±5.04 years. Mild anchor pull-out was observed in the Ant area in three cases, Mid in two cases, and Post in one case. The average pull-out length according to location was 1.50 mm in the Ant, 1.79 mm in the Mid, and 1.29 mm in the Post area. LT: lesser tuberosity.