Progression of digital osteoarthritis: a sequential scintigraphic and radiographic study

Hand radiographs and scintigraphy were obtained initially and at the 4-year follow-up in 15 patients with symptomatic osteoarthritis (OA) of distal and/or proximal interphalangeal joints. For each joint, a 0-15 score was obtained for the OA radiographic lesions read blind by the same observer. An abnormal isotope retention over a bone reference area was assessed and quantified. The predictive value of scintigraphy for the OA radiographic progression was confirmed and shown to be improved by a second investigation. During the study period, the percentage of radiographic OA joints increased from 66.3 to 76.6%, but joints showing an abnormal scan decreased from 40 to 22.5%. Progression of the OA radiographic score was closely related to scintigraphic changes. The mean difference between the final and initial OA score was -0.08 in joints with two normal scans (N = 115), +0.73 in joints showing a first abnormal and a second normal scan (N = 94) and +1.8 in joints with two abnormal scans (N = 14) or a scan becoming abnormal (N = 47). An abnormal scan appears to represent a transient event, and this event is associated with a period of progression of digital OA. Potentially, anti-OA therapies that suppress joint isotope retention might slow down OA progression. The magnitude of joint isotope retention was positively correlated with the OA radiographic score established at the same time (R = 0.61 and P < 0.001), but showed no predictive value for progression of the latter.