The device has a first determining unit for determining vector characteristics of a resultant of forces responsible for usury of a glenoid surface (G) from geometric usury characteristics provided by a second determination unit. A third determination unit determines a modified shoulder joint configuration from the vector characteristics of the resultant of forces supplied by the first determination unit by taking into account of action of the resultant of forces responsible for usury of the glenoid surface on articular cooperation between a scapula (S) and a humerus (H) of a patient. An independent claim is also included for a method for determining an implantation configuration for implanting a glenoid prosthetic component of a shoulder prosthesis in a scapula of a patient.
