Background: Irreparable rotator cuff tears are common and difficult to treat. Techniques for "filling the loss of substance" require fixation to the rotator cuff stump (tendon augmentation) or to the glenoid (superior capsular reconstruction), which are complicated by the narrow working zone of the subacromial space. The main objective of this study was to determine whether a braided graft of gracilis (GR) and semitendinosus (ST) could fill a loss of tendon substance from an irreparable rupture of the supra-and infraspinatus, by fixing the graft to the greater tuberosity and the spine of the scapula. Methods: This was a cadaveric study with the use of ten specimens. The GRA and ST tendons were harvested, braided and reinforced with suture. An experimental tear of the supraspinatus (SS) and upper infraspinatus (IS) retracted at the glenoid was made. The GRAST transplant was positioned over the tear. The transplant was attached to the greater tuberosity by two anchors and then attached to the medial third of the scapular spine by transosseous stitching. The percentage of filling obtained was then measured and passive mobility of the shoulder was assessed. We proceeded to the same technique under arthroscopy for a 73 years old patient whom we treated for a painful shoulder with irreparable cuff tear. We inserted a GRAST graft using arthroscopy. Results: The Braided-GRAST allowed a 100% filling of the loss of tendon substance. Mobility was complete in all cases. Conclusion: This technique simplifies the medial fixation and restores the musculo-tendinous chain where current grafting techniques only fill a tendinous defect. The transplant could have a subacromial "spacer" effect and lower the humeral head. The donor site morbidity and the fate of the transplant in-vivo are two limits to be discussed. This anatomical study paves the way for clinical experimentation.