Significant hindlimb static weight-bearing asymmetry persists for 40-weeks in a longitudinal study in two widely used rat models of surgically induced osteoarthritis knee pain

Our findings show significant, reproducible and long-lasting static weight-bearing asymmetry in the hindlimbs of both models (but not the sham-control group) for the 40-week study duration. Significant mechanical hypersensitivity developed in the ipsilateral hindpaws of the ACLT + MMx model (PWTs ≤8 g) which reversed spontaneously by ∼8-12-weeks. In the ACLT and the sham-groups, significant mechanical hypersensitivity did not develop in the ipsilateral hindpaws. In conclusion, hindlimb static weight-bearing asymmetry is a long-lasting, significant pain behavioral endpoint in these models suitable for assessing novel disease-modifying OA therapeutics and/or analgesic drug candidates aimed at alleviating unrelenting chronic OA knee pain in patients.