Figure 2.

Method of measuring the remaining neck (a) and the position of tip of the stem. We measured the distance between the tip of the stem and the inner cortex and calculated the ratio between these distances. Ratio between lateral and medial distance is b/c.The neck resorption ratio (NRR) is calculated by dividing the distance between the medial tip of the collar and the medial apex of the remaining neck (d) by the length of a straight line traced from the medial tip of the collar to the apex of the lesser trochanter (e).