A surgical cutting tool, instrument, kit and system are disclosed, which are adapted for use during in total hip (or shoulder) replacement surgery. The invention optimally and efficiently removes excess bone (osteophytes) and soft tissue from the rim of a hemispherical component such as an implanted acetabular shell, prior to insertion of a liner. The surgical instrument includes an elongated obturator adapted to be removably attached to the acetabular component. An elongated reamer tool has a cannulated central boss for receiving the obturator. The tool has an upper end adapted to be coupled to a powered tool driver, and a lower end provided with a pair of spaced apart blades adapted to engage the rim of the acetabular component and be driven to remove the excess bone fragments from the rim of the implanted shell component.