Subtle variations in hip morphology associate with risk of hip osteoarthritis (OA). However, validated accurate methods to quantitate hip morphology using plain radiography are lacking. We have developed a Matlab-based software-tool (SHIPs) that measures 19 OA-associated morphological-parameters of the hip using a PACS pelvic radiograph. In this study we evaluated the accuracy and repeatability of the method. Software accuracy was assessed by firstly measuring the linear ratio of 2 fixed distances and several angles against a gold-standard test radiograph, and secondly by repeated measurements on a simulated AP radiograph of the pelvis (reformatted from CT-data) that was digitally rotated about 3-axes to determine the error associated with pelvic mal-positioning. Repeatability was assessed using 30-AP Pelvic radiographs analysed twice (intra-observer), by 2 readers (inter-observer), and finally, using 2 pelvic radiographs taken in 23 subjects (n=46 radiographs) taken same day after re-positioning (short-term clinical-practice variability), and was expressed as coefficient of variation (CV%).Introduction
Methods
