Experimental design to study the effect of PAM on subchondral bone loss in ACLT- induced osteoarthritis. (a) Experimental scheme. (b) Typical Micro-CT images selected of a highly representative subchondral bone sample for each group. (A,B) Sham-operated group, (C) short-term treatment with PAM, (D) long-term treatment with PAM, (E-H) ACLT-induced osteoarthritis at 2, 4, 6 and 14 weeks. Marked differences in the microarchitecture of subchondral bone were observed.