Objective To correlate histopathological and radiographic features of distal and proximal interphalangeal (DIP and PIP) joints in order to test whether the use of an x-ray examination would be beneficial to the classification/diagnosis process of hand osteoarthritis (OA).

Methods DIP and PIP joints were obtained from post mortem specimens (n=40). Plain x-rays of the DIP and PIP joints were taken and radiographic OA was determined by the Kellgren and Lawrence classification. Individual radiographic features were scored according to the method described by Altman. Joint samples were prepared for histological analysis; cartilage damage was graded according to the Mankin scoring system. Spearman's correlation was applied to examine the relationship between histological and radiographical changes. Differences between groups (bony swelling vs no bony swelling) were determined by Student t test.

Results A highly significant correlation was found between histological (Mankin score) and radiographic (Kellgren/Lawrence score) changes in the investigated DIP (r_s=0.87, p<0.0001) and PIP (r_s=0.79, p<0.0001) joints. A subgroup of patients (37.5% for DIP and 18.8% for PIP joints) showed advanced radiographic changes (Kellgren/Lawrence score ≥2) in joints without clinical bony swelling. Histologically, the mean Mankin scores accounted for 11±1.66 for DIP and 9.67±2.4 for PIP joints.

Conclusion On the basis of histopathological changes of DIP and PIP joints, this investigation demonstrates the validity of x-ray examinations and supports the use of plain radiography in the diagnosis of hand OA and in the classification of hand OA in clinical trials.