Fig. 6

Example calculation of proximal radius saw guide placement error. Registration of the CT (a red) and sCT (b blue) optical scan bone model (without saw guide) to the micro-CT surface model (green). c The registered CT (red) and sCT (blue) optical scan 3D bone models including the relative position of each optical scan’s saw guide model. d. The isolated saw guides with their relative positions, revealing the displacements of the CT saw guide (red) and sCT saw guide (blue) relative to the saw guide planning (green). e The reference box (black) is selected as the region of interest on the optical scan (red) to compare to the reference box of the planning (green) in order to calculate the transformation matrix T with eight corresponding placement errors. Relative to the planning position: Z-value increases when translating in proximal direction, Y-value increases when translating away from the bone, X-increases when translating to the left