Patent ID: 8231630

Claim:
A bone cutting assembly comprising: a. a guide pin having a distal tip that may be securely inserted into a bone to define a cutting axis, the guide pin having a longitudinal axis; b. a housing having a cam surface and features for temporarily securing the housing to the bone, wherein the cam surface has a parabolic shape when viewed in a direction transverse to the longitudinal axis and the cam surface has a circular shape when viewed from above in the direction of the longitudinal axis; c. a burr mounting arm that rotatably and slidably fits onto the guide pin so that the burr mounting arm can swing around the cutting axis and also translate up and down the guide pin; in which the burr mounting arm acts against the cam surface as it is swung around the guide pin, so that the arm is caused to move up or down relative to the guide pin by the action of the cam surface.