(A) Study diagram; mice were treated biweekly with subcutaneous injections; whole knees were fixed for micro–computed tomography (micro-CT) analysis 4 weeks after ACLT. (B) Representative micro-CT images showing three-dimensional reconstruction of coronal sections. Scale bars, 1 mm. (C to L) Morphometric parameters of tibia subchondral trabecular bone. Anti-GDF8 treatment preserved bone volume fraction [BV/TV % (C and D), drug × injury interaction, P = 0.023], trabecular thickness [Tb.Th (E and F), drug × injury interaction, P = 0.017], and partially preserved trabecular number [Tb.N (G and H), drug × injury interaction, P = 0.020] 28 days after ACLT. There were no significant effects of ACLT or anti-GDF8 treatment on connectivity density [Conn.D (I and J)], but anti-GDF8 treatment protected against a loss of structure model index [SMI (K and L), drug × injury interaction, P = 0.047]. N = 9 mice per group. *P < 0.05, ***P < 0.005, and ****P < 0.001 represent Šidák’s multiple comparison post hoc tests performed when significant interactions were detected via mixed models (C, E, G, I, and K); *P < 0.05 via independent sample t test (D, F, H, J, and L).