The articular topographies of 46 osteoarthritic thumb carpometacarpal joints were quantitatively analyzed, as were their variations with gender, age, site, and anatomic osteoarthritic stage. It was found that, for osteoarthritic thumb carpometacarpal joints, (1) the opposing articular surfaces of elder and severely degenerated joints are more congruent than those of middle-aged and minimally or moderately degenerated joints, although the articular contact area is not significantly different when accounting for thinning of the cartilage layer with age or disease; (2) significant changes in joint topography due to osteoarthritis only occur in severely degenerated joints; (3) female joints are less congruent, have smaller contact areas, and are likely to experience higher contact stresses than male joints for similar activities of daily living which involve similar joint loads; and (4) osteoarthritic changes are less severe on the dorso-ulnar aspect of the trapezium and dorsal aspect of the metacarpal, which are known to be low load-bearing regions.