Abstract: The present application concerns a shoulder prosthesis assembly. The shoulder prosthesis assembly comprises a humeral stem including a first articulating coupling means, a base portion of a substantially disc shaped geometry including a second articulating coupling means. Said first articulating coupling means and said second articulating coupling means connect the stem to the base portion. The ratio between the circumference of the disc shaped base portion and the peripheral thickness of the disc shaped base portion is at least 18:1.

Abstract: The present application relates to an artificial joint implant comprising a first element with a socket and a second element with a ball head. The socket is at least hemispherical and said ball head is inserted in said socket such as to form a ball-and-socket connection between said first element and said second element. Movement of said ball head in said socket is restricted in at least one degree of freedom by means of a at least one protrusion engaged in a at least one groove, wherein said at least one protrusion is provided on said socket and said at least one groove is provided on said ball head or vice versa.