OARSI histopathology grading and staging scores. OARSI histopathology grading and staging scores were determined in sham (control), and contralateral and ipsilateral treatments of both NM and FM groups of animals over 20 weeks. Tibial joint surfaces from (a) sham and (b) contralateral and ipsilateral treatments were assessed independently of femoral (c) sham and (d) contralateral and ipsilateral joint surfaces. Mean OARSI scores ± standard error are shown. Significantly higher scores were observed in NM contralateral femurs than NM sham femurs at 2 and 12 weeks (statistics not shown). Both ipsilateral surfaces had significantly higher OARSI scores than shams at all time points, except NM ipsilateral surfaces at 2 weeks (statistics not shown). Statistical analysis is done for each individual time point to indicate significantly different means among each of the four contralateral and ipsilateral treatments. Similar means at each time point are indicated by the same letter (a, b, and c), whereas significantly different means at each time point are indicated by different letters (P < 0.05; n = 4). FM, forced mobilization; NM, nonmobilized; OARSI, Osteoarthritis Research Society International.