The objective of the present study was to test the hypothesis
that experts recognize repair of erosions and, if so, to determine
which, if any, morphologic features permitted them to recognize
the repair. We also tested whether scoring by a standard
method detected repair. Seven experienced readers of
radiographs in rheumatoid arthritis were presented with 64 sets
of single joints-of-interest at two time points, randomized and
blinded for the correct sequence. The readers assessed which
joint was better, and recorded whether any of six specific
features were seen. Two independent readers, experienced in
scoring by the van der Heijde-modified Sharp method who were
not on the expert panel, then scored the complete films that
included the joint-of-interest. The panel agreed very well on
which of two joints was better, and, even though they did not
know the true sequence, the panel accurately assigned a
sequence slightly better than chance alone (58%) but worse
than their agreement on which image was 'better or worse'
(78%). The readers therefore indirectly assigned repair by
choosing the second film as the best. Putative repair features
were seen in cases of both repair and progression, and were not