The Efficacy of Injectable Atelocollagen in Arthroscopic Rotator Cuff Repair: A Systematic Review and Meta-Analysis.

A rotator cuff (RC) tear can result in shoulder dysfunction and pain. Arthroscopic repair has been used for complete or advanced partial tears. However, the rates of retear and non-healing remain a challenge postoperatively. We aim to investigate the efficacy of injecting atelocollagen in combination with arthroscopic repair in patients with complete or partial RC tears. We performed an electronic search using PubMed, Scopus, Web of Science, and the Cochrane Library up to the 7th of October 2025. Randomized controlled trials (RCTs) and cohort studies that evaluate atelocollagen as an adjunct to arthroscopic repair of RC tears were included. Primary outcomes were retear rate (Sugaya IV-V) and pain (visual analog scale (VAS)), and functional outcomes (American Shoulder and Elbow Surgeons score (ASES) and Korean Shoulder Score (KSS)) at 12 months. Additionally, we evaluated the overall risk of bias (ROB) of each included study using the RoB2 tool for RCTs and the ROBINS-I tool for cohorts. Pooled analyses were performed using Review Manager 5.4 with random-effects modeling applied when heterogeneity was detected. Five studies, including a total of 743 patients, were included, with 376 using the intervention. We found a lower retear rate in the atelocollagen group that was statistically insignificant (RR=0.75, p=0.25). Additionally, the pooled analysis of VAS pain score showed a non-significant reduction in favor of atelocollagen (MD=-0.31, p=0.45). Functional outcomes at 12 months revealed no significant differences: ASES score (MD=-2.16, p=0.06) and KSS score (MD=0.26, p=0.91). For shoulder ROM, we detected non-significant differences in forward flexion (MD=-1.03°, p=0.73), external rotation (MD=-0.86°, p=0.74), or internal rotation (MD=0.06, p=0.81). Despite statistical insignificance, atelocollagen administration during RC arthroscopic repair showed a consistent trend toward improved healing, particularly in retear rate and VAS pain. Further large and well-designed trials are warranted to confirm its clinical benefits.