A guide device for assessing the length and offset of a hip of a patient is disclosed. The guide device includes an overlay portion and an alignment portion. The overlay portion is configured to enable assessment of the relative location of the guide device to the original femoral head of a patient using a marking on the overlay portion. Reference points for positioning the guide device are created on the femur. When the guide device is positioned at the reference points it can be used to position a replacement femoral head in the same position as the patients original femoral head by aligning the replacement femoral head with the marking on the overlay portion.
