Fig. 3

a and b Both images show a cut-out from radiographic images performed on a patient. Measurements were performed as displayed. a is cut from an EOS® full-leg AP radiograph. b is cut from a standard pelvic AP radiograph. The horizontal line represents Hilgenreiner’s line whereas the vertical line represents Perkin’s line. Reimers described the MP as the extent of the calcified femoral head at its widest point lateral from Perkin’s line divided by the total width of the calcified femoral head at its widest point reported as a percentage [6]. On these images the MP is 25% (0.25 × 100%) for the right hip and 33% (0.33 × 100%) for the left hip