Objectives. - to assess quantitatively the relative contribution of joint degeneration characteristics such as osteophytes (OS), joint space narrowing (JS), subchondral sclerosis (SS), subchondral cysts (SC), lateral deformity (LD) and cortical collapse (CC) to the Kellgren and Lawrence (K-L) score grade of hand osteoarthritis (OA).

Methods. - Radiographs of both hands were taken from 1245 study participants, native Chuvasha, Russian Federation. K-L score and the six above-mentioned characteristics were assessed on 15 joints of each hand. Multiple regression and correlation analyses were performed: for rows of hand joints and groups of thumb joints, and for the aforementioned rows but assigned into six age groups.

Results and Conclusions. - According to the K-L grading system the relative contribution of OS to joint degeneration was high in all stages of the process. JS and SS played an important role in determining the K-L score in persons younger than 40 but less so in older people. Conversely, influence of SC and LD is insignificant at the onset of OA (i.e., in young persons), yet in older people it was a leading determinant of the K-L score. CC exerts no influence on the K-L score of OA.