Fig. 2

Surgical portals and incision. a Front view: The anterosuperior portal (A with black color) which is left by the partly closed incision on the coracoid with 5 mm left. An anterosuperior lateral portal (C with black color) was also established through the guidance of arthroscopy. b Lateral view: A standardized posterior portal (B with black color) was established. c An incision measuring 2.5 cm was made, which began from 1 cm under the coracoid process in the direction of the axilla. An osteotomy of the coracoid process was performed, and two bone tunnels were drilled with a distance of 6 mm in the cut bone block along its axis. High-strength sutures were pulled into the central hole of a suture button and then pulled together to the proximal bone tunnel. d After freshening the bone graft, the incision was partly closed with 5 mm left as the anterosuperior portal