Inter- and intraobserver reliability of the Crowe and Hartofilakidis classifications in the assessment of developmental dysplasia of the hip in adult patients

Background The purpose of this study is to investigate the inter- and intraobserver reliability of Crowe and Hartofilakidis classifications in the assessment of developmental dysplasia of the hip in adult patients. Materials and methods Two consultant orthopedic surgeons classified 141 dysplastic hips on 103 standard anterior–posterior pelvis radiographs according to the Crowe and Hartofilakidis classifications. Assessments were performed in random order by each observer on two separate occasions, at least 4 weeks apart. Kappa statistics were used to establish a relative level of agreement between observers for the two readings and between separate readings by the same observer. Results At the first readings, interobserver reliability analysis revealed kappa coefficient of 0.71 for the Crowe classification and 0.54 for the Hartofilakidis classification. At the second reading, the kappa coefficient was 0.72 for the Crowe classification and 0.75 for the Hartofilakidis classification. Intraobserver reliability analysis revealed kappa coefficients of 0.71 for the Crowe and 0.80 for the Hartofilakidis classification for observer A, and 0.76 and 0.70 for observer B. Conclusions In conclusion, we have found substantial inter- and intraobserver agreement for Crowe classification and substantial to moderate agreement for Hartofilakidis classification in this study. Both classification systems assess the different aspects of developmental dysplasia of hip in adults. Each system has advantages and disadvantages. We suggest using both of these classifications together to increase the accuracy.