[Reproducibility in the roentgenological assessment of coxarthritis]

The "German Society of Orthopaedic Surgery and Traumatology (DGOT)" is trying to support the application of standardized and reproducible criteria in diagnosis and therapy of osteoarthritis. As radiographs are a primary measure of outcome at present, the objective of this study was to investigate the reproducibility of radiologic assessment in hip osteoarthritis using different radiographic variables. 3 investigators read 100 hip joints on 50 pelvis radiographs at two time-points for the presence and severity of individual radiographic features: joint space narrowing (JSN), osteophytes, sklerosis, subchondral cysts and deformity of the femoral head. Additionally the summary grade of Kellgren and Lawrence (1963) and Scott et al (1992) was assessed. Intra- and inter-rater-reliability were calculated by intra-class-correlation-co-efficient (ICC). The results regarding intra- and inter-rater-reliability show excellent values for superior JSN, femoral head deformity and the summary score. The radiologic assessment of medial JSN, osteophytes and acetabular sklerosis depends on the level of the investigator's experience. Perifoveal osteophytes and subchondral cysts do not seem to be have sufficient reproducibility. The results of our investigation show, that a reliable radiological classification of the severity of hip osteoarthritis is possible by assessment of certain individual radiographic features or a summary grade.