Kit for interpositional arthroplasty

System Interpositional implant for creation or modification of an orthopedic joint within the body of a mammal, system (154) comprising one or more devices for each of the stages for: a) preparing the joint to receive the Interpositional implant (156 , 158, 160, 254), wherein the device includes a smoothing device for preparing one or more surfaces within the area of ​​a joint: b) determining an appropriate implant size for a particular joint (162), wherein the device incorporates a feeler adapted to measure one or more dimensions of the joint; c) determining an appropriate thickness (170, 172) of the implant, wherein the device for determining an appropriate implant thickness includes a plurality of trial implants of one or more dimensions and / or configurations; d) inserting the implant into the joint (164), wherein the device comprises a plurality of opposing jaws together.