Surgical tools are disclosed for minimally-invasive planing of bone surfaces that will support prosthetic implants, such as cartilage-repair implants. Such planing tools must create smooth surfaces that will closely fit the anchoring surface of an implant. Such tools can use a rotating cylindrical burr, partially covered by a cowl having adjustable components to control grinding depth and bone curvature. Burrs can be mounted on the ends of rotating shafts, or they can be angled, using drive-coupling interfaces. In other embodiments, shaver or burr tools can be supplemented by accessory-type devices (such as suction tubes, cautery tips, and pinchers) that can be extended beyond the normal working tip of a tool, to enable additional functions that will be useful during surgery.
