Material and method3D print-outs of a glenoid and a coracoid process were obtained from CT scans of a patient showing anterior shoulder instability with significant bone defect. Four types of coracoid fixation were implemented: 1 or 2 4.5 mm malleolar screws, and 1 or 2 Endobuttons. Three specimens per assembly were placed on a specific test bench. Lateromedial bone-block compression was exerted at 0.1 mm/sec at 3 points: superior, central, inferior. The resultant force and bone-block displacement were recorded.ResultsMean fixation rigidity with 1 screw, 2 screws, 1 Endobutton and 2 Endobuttons was respectively 158 N/mm (range, 133–179), 249 N/mm (241–259), 10 N/mm (5–13) and 14 N/mm (13–15), with significant difference between the screw and Endobutton groups (p < 0.001). Displacement was greater with 1 than 2 Endobuttons under superior or inferior force, while the difference was non-significant under central force (7.45 vs 6.93 mm; p = 0.53)ConclusionsScrew fixation showed greater rigidity, while the Endobutton assembly showed less tension, leading to greater bone-block mobilization. The interest of using two Endobuttons is to reduce displacement under polar pressure. the present biomechanical study confirmed the mechanical vulnerability of bone-blocks fixed by endobutton until consolidation is achieved.Level of evidenceBiomechanical study.