Radiographic grading for knee osteoarthritis. A revised scheme that relates to alignment and deformity.

To develop a radiographic grading scheme for osteoarthritis of the knee that would relate to arthritic progression and deformity.The scheme of Scott, et al was revised to include new fields of Tibial Erosion and Subluxation; the fields of Tibial Osteophytes and Sclerosis were removed. The worst affected compartment only was scored on frontal Standardized Knee Images, which were used to define knee alignment variables.The interreader reliability (kappa = 0.92) and correlation for total scores (r = 0.94) were both excellent (p < 0.001). Individual field scores and total knee scores both correlated well with most limb alignment variables, especially the hip-knee-ankle angle (r = 0.77, p < 0.001).These findings encourage further evaluations for outcome measurement, diagnostic sensitivity, and sensitivity to define arthritic change over time.