Dealing with massive and irreparable rotator cuff tears presents intricate challenges. Concerning elder patients, either conservative management or reverse shoulder arthroplasty could be the most appropriate treatment. On the other hand, in younger patients, there is a wide spectrum of solutions, most of them being under evaluation and not completely validated. The complexity increases when a greater tuberosity avulsion occurs at the same time. Regardless of whether surgical fixation is performed, there is a risk for bone resorption, which would result in the posterosuperior cuff's insertion spot loss. In this case, the surgeon is expected to simultaneously manage the bone loss and the tendon tear. The Calcaneum-Achilles Tendon Allograft (CalATA) therefore appears to play an interesting role due to its solid bone-tendon structure. This Technical Note aims to present the CalATA technique, which consists in both tendon and bone deficiency restoration in massive rotator cuff tears with greater tuberosity resorption.