Contour lock guides

1. A patient-specific surgical guiding tool for positioning an alignment element, the patient-specific guiding tool comprising:

a central contact element configured to fit onto an area of a socket of a ball-and-socket joint, wherein the ball-and-socket is an acetabulum;

one or more lateral contact elements configured to fit onto at least one of the following: a rim of the socket, a bone surrounding the socket, and a ligament around the socket, wherein at least one of the one or more lateral contact elements is configured to fit onto a posterior notch of a transverse ligament of the ball-and-socket joint; and

a positioning element comprising a feature configured to receive the alignment element,

wherein at least one of the one or more lateral contact elements comprises a contact surface corresponding to at least part of an outer contour of the socket and the central contact element comprises a contact surface corresponding to at least part of an inner surface of the socket.

2. The patient-specific surgical guiding tool of claim 1 , wherein the rim of the socket defines at least one of a substantially circular shape or a roughly elliptical shape having a center defined by a circle best fitting the substantially circular shape or by an ellipse best fitting the roughly elliptical shape, wherein the one or more lateral contact elements comprises at least two lateral contact elements configured to contact the socket in at least three contact points, wherein, for each contact point of the at least three contact points, an angle between a first line connecting the contact point and the center and a second line connecting an adjacent contact point and the center is not greater than 180°, wherein the adjacent contact point is one of the at least three contact points.

3. The patient-specific surgical guiding tool of claim 1 , further comprising a connecting structure, the one or more lateral contact elements extending from the connecting structure.

4. The patient-specific surgical guiding tool of claim 3 , wherein the connecting structure corresponds with the positioning element.

5. The patient-specific surgical guiding tool of claim 1 , wherein at least one of the one or more lateral contact elements corresponds with an anatomical feature around the socket.

6. The patient-specific surgical guiding tool of claim 1 , wherein the alignment element comprises at least one of the following: a pin, a wire, a screw and a drill.

7. The patient-specific surgical guiding tool of claim 1 , wherein the positioning element corresponds to at least one of the central contact element and the one or more lateral contact elements.

8. The patient-specific surgical guiding tool of claim 1 , wherein the socket is an acetabulum cavity.

9. A method of positioning an alignment tool on bone, the method comprising:

positioning a surgical guiding tool onto a socket of a ball-and-socket joint, wherein the ball-and-socket joint is an acetabulum, and wherein the surgical guiding tool comprises:

a central contact element configured to fit onto an area of the socket;

one or more lateral contact elements configured to fit onto at least one of the following: a rim of the socket, a bone surrounding the socket, and a ligament around the socket, wherein at least one of the one or more lateral contact elements is configured to fit onto a posterior notch of a transverse ligament of the ball-and-socket joint; and

a positioning element comprising a feature configured to receive the alignment tool;

positioning the alignment tool on or into the bone of or around the socket by inserting it through an aperture defined by the positioning element; and

removing the surgical guiding tool from the socket.

10. The method of claim 9 , wherein the alignment tool comprises a pin and step alignment element, and wherein removing the surgical guiding tool further comprises removing the surgical guiding tool from the socket along a direction of a longitudinal axis of the alignment element without removing the alignment element from the bone.