Fig. 2

A box aligned in the scapular plane (165 × 50x30mm), was placed around the virtual scapular blade (with the planning software CASPA). Differences in glenoid version and inclination could thereby be reproduced with reference to the scapular or horizontal plane, respectively. This was done in order to prevent incorrect positioning when mounting the models on the biomechanical apparatus. The scapula was fixed in a vice at the box level, with the scapular plane (orange plane) oriented strictly vertically, the glenoid facing upward. This defined glenoid version. Glenoid inclination was incorporated into the printed models with respect to the horizontal plane according to the predetermined values for all models. The scapular models were fixed on a plate on top of a bearing plate which could be levered upward to exert a compression force of 100N. With the humerus fixed, the anteroposterior (AP) and superoinferior (SI) translatable plate with its fixed scapula was rotated to simulate different shoulder flexion angles (60°, 90°, 120°)