If zero femoral elevation can be achieved for radiography, the lateral distal femoral angle measurements do not vary much with mild femoral rotation (±5°)
The iliac horizontal diameter is the recommended variable and maximum obturator foramen width is an acceptable variable in order to evaluate slight pelvic rotation
The position of a stable stem can appear different on subsequent re-evaluations, but this may be due to variability associated with inconsistency of positioning of the patient and limb