Objectives. The objective of this study was to compare the damage to the rotator cuff tendons caused by four different anchor systems. Methods. 20 cadaveric human shoulder joints were used for transtendon insertion of four anchor systems. The Healix Peek, Fastin RC, Bio-Corkscrew Suture, and Healix Transtend anchors were inserted through the tendons using standard transtendon procedures. The areas of tendon damage were measured. Results. The areas of tendon damage (mean±standard deviation, n = 7) were 29.1±4.3mm2 for the Healix Peek anchor, 20.4±2.3mm2 for the Fastin RC anchor, 23.4±1.2mm2 for the Bio-Corkscrew Suture anchor, 13.7±3.2mm2 for the Healix Transtend anchor inserted directly, and 9.1 ± 2.1mm2 for the Healix Transtend anchor inserted through the Percannula system (P < 0.001 or P < 0.001, compared to other anchors). Conclusions. In a cadaver transtendon rotator cuff repair model, smaller anchors caused less damage to the tendon tissues. The Healix Transtend implant system caused the least damage to the tendon tissues. Our findings suggest that smaller anchors should be considered when performing transtendon procedures to repair partial rotator cuff tears.