Reading radiographs in pairs or in chronological order influences radiological progression in osteoarthritis

To determine the influence of the order in which a series of radiographs were read on the sensitivity to change over a 2-yr follow-up period in patients with osteoarthritis (OA) at multiple sites.

Radiographs of 20 patients with OA in at least two joint sites were obtained at baseline and after 2 yr, and scored according to the consensus of two readers. Joint space narrowing (JSN) and osteophytes were graded (0-3) in the hand, hip and tibiofemoral joints. The cervical (C2-7) and lumbar spine disc spaces (L1-S1) were graded (0-3) for disc space narrowing (DSN) and anterior osteophytes. Films were read by two different procedures: in pairs, with an unknown time sequence and in chronological order. Radiological progression was defined as an increase of at least one grade in JSN, DSN or osteophyte total scores. The two procedures were compared using standardized response means (SRM).

The SRM for changes in JSN or DSN progression scores in the hands, hips, knees and spine were, respectively, 0.00, 0.00, 0.32, 0.13 and 0.38, 0.32, 0.56, 0.18 for the paired and chronological readings. The SRM for changes in osteophyte progression scores in the hands, hips, knees and spine were, respectively, 0.39, 0.20, 0.32, 0.38 and 0.41, 0.37, 0.56, 0.66 for the paired and chronological readings.

When assessing radiological progression in OA, reading a series of radiographs in chronological order tended to be more sensitive to change over a 2-yr follow-up period than reading in pairs with an unknown time sequence.