The purpose of this study was to measure subchondral bone mineralization changes associated with early osteoarthritis onset in the cranial cruciate deficient dog using computed tomography and dual energy x-ray absorptiometry. Cruciate rupture was initiated in seven dogs and bone mineralization changes were measured at 1, 3, 6, 9, and 12 months post-cruciate rupture. Computed tomography revealed significant decreases in bone mineral density of the femoral condyles and patella at all time points when ruptured limbs were compared to unaffected limbs and baseline values. Dual energy x-ray absorptiometry found very little significant change in bone mineral density or bone mineral content. Since a decrease in bone mineral density is a hallmark of early osteoarthritis, we concluded that computed tomography is an accurate measure of bone mineral density changes and it is superior to dual energy x-ray absorptiometry for clinical diagnosis of early osteoarthritis onset.