In 105 knees, the roentgenographic classifications of hemophilic
arthropathy of Arnold and Hilgartner, of Pettersson et al., and of a new
system were compared. The amount of interobserver agreement (between two
observers) was good for all three systems and, for all three, there was a
good correlation between progressive severity of the lesion and decreasing
function of the joint. The system of Pettersson et al. was better than that
of Arnold and Hilgartner for grading severe arthropathy, but it was not
better than the new, simplified system. The new system is a four-sign,
7-point classification, in contrast to the eight-sign, 13-point system of
Pettersson et al.