A design method for design of an individually customized rig (600), said rig (600) having a hollow tubular shell (510) open at both ends, characterized in that the interior of said shell defines at least first and second intersecting circular cylinders and wherein the design method for said rig (600) comprises the steps A first damage identification step (101) comprising identifying a bone and or cartilage area (4) in a patient comprising a bone and or cartilage damage (5) and presentation of a 3D view (9) of said identified area using a software program A second virtual model making step (14) comprising making a 3D model of a virtual rig comprising a step of virtually placing in said 3D view (9) at least two circular shapes (303), wherein each circular shape (303) partly overlaps at least one other circular shape (303), and wherein the combined area (20) of the circular shapes covers or partly covers said identified bone and or cartilage damage (5) and wherein positioning data is used to create the position and interior of said hollow tubular rig shell (510) of the virtual rig which is open at both ends and wherein selection of at least first and second intersecting circular cylinder rig is based on the selected sizes of the circular shapes (303), or slightly larger, and wherein a positioning surface (560) of the virtual rig is created which is a bone and or cartilage-engaging end of said hollow tubular shell (510) and wherein said positioning surface (560) is adapted to face and align to the surface structure surrounding the hollow circular shapes of the rig when the rig is placed in a virtual model of the joint A third production step (34) comprising producing a rig (600) according to the virtually created rig which is adapted to mimic the volume and shape according to said created virtual model of the rig as well as the rig as such, a method for placement of the rig in a joint and a tool for placing the rig.La présente invention concerne un procédé de conception
