Forsthuber LTK, Elkins JM, Miner TM, et al. - This study was intended to evaluate the arthroplasty surgeon accuracy in making spinopelvic measurements. Forty-four lateral lumbar radiographs were reviewed by five fellowship-trained or in-training arthroplasty surgeons in two sessions. Researchers compared surgeon measurements with those made by experienced engineers. intraclass coefficients were estimated and interpreted. In comparison with traditional radiographic measurements, surgeon intraobserver and interobserver reliability in making novel radiographic measurements were low. It was shown that surgeon reliability in making traditional measurements of the pelvic tilt and sacral slope was very poor in comparison with experienced assessors applying software-based measurement.