All-suture suture anchors (ASAs) are being increasingly used in modern arthroscopic rotator cuff repair (RCR). Peri-anchor cyst formation (PCF) is a well-known phenomenon that occurs following arthroscopic rotator cuff repair with ispoly-L-lactic acid (PLLA) anchors, however, little is known about the rate and severity of PCF formation following ASA use. To our knowledge, there are no studies investigating the incidence of PCF of both anchor types in the same patient. The objective of this study was to compare the rate and severity of PCF after ASAs in modern arthroscopic rotator cuff repair compared to PLLA anchors. The hypothesis was that ASAs would have a lower incidence of peri- anchor cyst formation compared to PLLA anchors.
23 patients (24 shoulders) underwent double-row arthroscopic RCR from 2012-2017. ASAs were implanted in the medial row and PLLA anchors were placed in the lateral row. Patients underwent shoulder magnetic resonance imaging (MRI) at a median follow- up of 27.8 months to evaluate for PCF formation. Cyst formation was graded from a 0 (no fluid) to a 4 (fluid diameter > twice anchor diameter) using a previously established grading system. MRIs were graded by a fellowship-trained musculoskeletal radiologist. Patients underwent a post-operative physical exam, University of California at Los Angeles (UCLA) shoulder survey, and American Shoulder and Elbow Surgeons (ASES) survey.
93% of PLLA anchors displayed a grade 0 cyst formation compared to 77% of ASAs (p=0.054). No PLLA anchors had a grade 3 or 4 cyst. 10% of ASAs were graded as a 3 or 4. Median UCLA score was 33, while median ASES score was 91.65. Median post- operative forward flexion was 140 degrees, while median external rotation was 40 degrees. 100% of patients had grade 4 or 5 supraspinatus and infraspinatus strength on exam.
ASAs demonstrated a higher rate of fluid surrounding anchors and had more cases of high-grade peri-anchor cyst formation than PLLA anchors.