An orthopaedic surgical instrument system comprising: a surgical reamer including an elongated shaft and a plurality of cutting flutes defined at a distal end of the elongated shaft , an attachment base comprising: a housing (2 34) including a main body , an elongated bore that is sized to receive the elongated shaft of the reamer and extends along a longitudinal axis of the main body, and a rail extending from the main body orthogonal to the longitudinal axis, and a locking knob secured to the housing and having a longitudinal bore aligned with the elongated bore of the housing that is sized to receive the elongated shaft of the reamer, the locking knob being rotatable between a first position in which the attachment base is permitted to slide along the elongated shaft of the surgical reamer and a second position in which the attachment base is locked into position on the elongated shaft of the surgical reamer, a mounting frame positioned on the rail, the mounting frame being configured to slide relative to the housing along the rail, and a cutting block removably coupled to the mounting frame, wherein the locking knob is operable to advance a section of the housing into engagement with the reamer when rotated to the second position characterized in that the housing of the attachment base includes a retaining flange configured to engage an inner rib of the locking knob to secure the locking knob to the housing. a surgical reamer including an elongated shaft and a plurality of cutting flutes defined at a distal end of the elongated shaft , an attachment base comprising: a housing (2 34) including a main body , an elongated bore that is sized to receive the elongated shaft of the reamer and extends along a longitudinal axis of the main body, and a rail extending from the main body orthogonal to the longitudinal axis, and a locking knob secured to the housing and having a longitudinal bore aligned with the elongated bore of the housing that is sized to receive the elongated shaft of the reamer, the locking knob being rotatable between a first position in which the attachment base is permitted to slide along the elongated shaft of the surgical reamer and a second position in which the attachment base is locked into position on the elongated shaft of the surgical reamer, a housing (2 34) including a main body , an elongated bore that is sized to receive the elongated shaft of the reamer and extends along a longitudinal axis of the main body, and a rail extending from the main body orthogonal to the longitudinal axis, and a locking knob secured to the housing and having a longitudinal bore aligned with the elongated bore of the housing that is sized to receive the elongated shaft of the reamer, the locking knob being rotatable between a first position in which the attachment base is permitted to slide along the elongated shaft of the surgical reamer and a second position in which the attachment base is locked into position on the elongated shaft of the surgical reamer, a mounting frame positioned on the rail, the mounting frame being configured to slide relative to the housing along the rail, and a cutting block removably coupled to the mounting frame, wherein the locking knob is operable to advance a section of the housing into engagement with the reamer when rotated to the second position characterized in that the housing of the attachment base includes a retaining flange configured to engage an inner rib of the locking knob to secure the locking knob to the housing. <EOS>