Prosthesis for the replacement of a joint, in which the prosthesis (1) comprises two prosthetic members (2, 3), each of which is configured for fixation to at least one of the bones in the joint, in the that one of the prosthetic members (2) comprises a first screw-like fixation member (4) that is configured for placement in at least one of the bones in the joint and the other prosthetic member (3) a second member (5) screw type fixation that is configured for placement in at least one other bone in the joint and wherein said a prosthetic member (2) comprises a receptacle member (6) and said other member (3) of prostheses a head member (7), wherein said receptacle member (6) is configured with a fixing pin (16) that can be inserted into a hole (8) in the first type fixing member (4) screw for fixing the receptacle member in the same, and wherein said head member (7) is configured with a fixing pin (19) that can be inserted into a hole (9) in the second screw type fixing member (5) for fixing the member of head therein, in which the hole (8) in the first screw-type fixing member (4) is at least partially configured to define a snap fit with the member fixing pin (16) (6) of receptacle, characterized in that the hole (8) in the first screw-type fixing member (4) is at least partially threaded (14) to allow, alternatively, the tightening or fixing by screwing in said hole of a member (33a； 33b) of locking which is configured to cooperate with a lockable member (34a, 34b) which is made in one piece with a second fixing member (5a, 5b), wherein said lockable member is configured for adjustable fixing with in relation to the blocking member and for fixing it, in an adjustment position, to the blocking member, in which said lockable member (34a； 34b) replaces together with said second fixing member (5a； 5b) the second member (5) screw type fixing with the head member (7) or a blocking member (33c； 33d) that is configured to cooperate with a lockable member (34c； 34d), wher
