Micro-CT analysis of subchondral changes over the time course. Knee joints from (a) NM and (b) FM groups of animals were assessed by micro-CT for morphologic changes in subchondral bone in contralateral and ipsilateral joints, compared with sham controls at 2, 12, and 20 weeks. Each sagittal slice at 12 and 20 weeks is shown at the same distance into the medial joint compartment (from the medial margin) as the corresponding histologic section in Figure 2. Subchondral trabecular architecture was maintained in both sham and contralateral joints, regardless of mobilization group. Note the more extensive subchondral spaces in FM compared with NM ipsilateral joints (white arrows). Sclerotic bone (S) appeared earlier in FM (12 weeks) than in NM ipsilateral joints (20 weeks). Collapse of the subchondral plate was evident in 20 week FM joints (arrowhead). All images are shown at the same magnification, indicated by the scale bars. CT, computed tomography; FM, forced mobilization; NM, nonmobilized.