All-Suture Anchors Exhibit Less Perianchor Fluid Formation Independent of Healing Quality Compared With PEEK Anchors in Arthroscopic Rotator Cuff Repair: A Propensity Score-Matched Comparative Study

Perianchor fluid collection may differ according to anchor material following arthroscopic rotator cuff repair (ARCR), but its relationship with tendon healing remains unclear. This study aimed to compare perianchor fluid collection between all-suture anchors (ASA) and polyetheretherketone (PEEK) anchors following ARCR and to evaluate its relationship with tendon healing at mid-term follow-up. A retrospective comparative study was performed on patients who underwent primary ARCR using either ASA or PEEK anchors. Propensity score matching (PSM) was applied to balance baseline variables, including age, sex, tear size, and bone mineral density. Clinical outcomes, including visual analog scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES) score, and range of motion (ROM), as well as structural integrity assessed by the Sugaya classification and perianchor fluid collection graded on magnetic resonance imaging (MRI), were evaluated at a minimum follow-up of 2 years. Perianchor fluid collection was also evaluated as absent (Grade 0) or present (Grade &#x2265;1). Correlation analysis between fluid collection and tendon integrity was performed. After PSM, 34 matched pairs (n=68) were analyzed. Both groups showed significant improvement in VAS and ASES scores (p<0.001), with no differences between groups in clinical outcomes, range of motion, or healing rates (76.5% in ASA vs. 82.4% in PEEK; p>0.05). Although the overall distribution of perianchor fluid collection grades was similar (p=0.106), the presence of fluid collection (Grade &#x2265;1) was significantly higher in the PEEK group (38.2% vs. 11.8%; p=0.023). A moderate positive correlation between fluid collection and Sugaya classification was observed in the PEEK group (r=0.606, p<0.001), whereas no significant correlation was found in the ASA group. ASA and PEEK anchors yielded comparable clinical outcomes and healing rates after arthroscopic rotator cuff repair at a minimum 2-year follow-up. Although perianchor fluid formation correlated with repair integrity in the PEEK anchor group, all-suture anchors demonstrated lower rates of perianchor fluid formation, with no significant association observed between fluid formation and healing quality in the ASA group. Level III, Retrospective Cohort Comparison, Treatment Study.