We compared the clinical outcome, complication rate and positioning of metal anchors used in the arthroscopic treatment of shoulder instability placed through the anteroinferior or subscapular portals. In an observational, case-control study carried out between 2014 and 2016, 33 patients underwent arthroscopic treatment for recurrent shoulder dislocation. The patients were allocated to the study group (n=17) in which the anchor was positioned through the subscapularis tendon portal and the control group in which the anchor was positioned through the anteroinferior portal. Shoulder function was assessed using various scores. The strength of the subscapularis muscle was measured using an electronic dynamometer and the positioning of the anchors was measured and compared using X-rays in the PA and Profile views. The use of the subscapularis portal proved to be safe in relation to neurovascular structures and improved the positioning of the anchor(s) in the anteroinferior aspect of the glenoid compared to the anteroinferior portal, allowing for a more orthogonal placement of the anchor(s). The portal through the subscapularis has no functional repercussions.