Inter- and Intraobserver Reliabilities of Four Different Radiographic Grading Scales of Osteoarthritis of the Knee Joint.

The purpose of this study was to investigate the interobserver and intraobserver reliabilities of four different radiographic grading scale of osteoarthritis (OA) of the knee joint, namely, Kellgren-Lawrence (KL), Ahlback, Brandt, and OA Research Society International (OARSI). One consultant orthopaedic surgeon and one rheumatologist who were familiar with these OA grading scales participated in the study. Radiological assessments were performed in random order by each observer on two separate occasions, at least 2 weeks apart.