Long-term temporal evaluation of ground reaction forces during developmentof experimentally induced osteoarthritis in dogs

Objective-To describe changes in vertical ground reaction forces (GRF) over 48 months in dogs with osteoarthritis (OA) of the stifle joint induced by transection of a cranial cruciate ligament (CCL). Animals-12 clinically normal adult dogs. Procedure-Vertical GRF (eg, peak f orce and impulse) were determined prior to and 1, 2, 3, 6, 10, and 12 month s after transection of the right CCL. In 7 dogs, data were also collected 2 4, 32, 38, 42, and 48 months after transection. Results-Vertical peak force and impulse were significantly decreased in the right hind limb at all times after transection, compared with baseline val ues. From 10 through 48 months after transection, vertical GRF remained ess entially static. Ground reaction forces in the unoperated (left) hind limb also changed significantly during the study. Left vertical impulse signific antly increased 3 months after transection, whereas at 24, 38, 42, and 48 m onths after transection, left vertical peak force was significantly decreas ed, compared with the baseline value. Mean intradog coefficients of variati on (CV) for peak vertical force and impulse ranged from 7.38 and 9.32, resp ectively, 1 month after transection to 1.96 and 2.76, respectively, at 42 m onths. Conclusions and Clinical Relevance-Vertical GRF in the affected hind limb e quilibrated approximately 10 months after CCL transection. Prior to this, f orce transmission across the affected stifle joint changed significantly ov er time. Intradog CV were small, indicating that GRF may be an appropriate outcome measurement for evaluation of OA development induced by CCL transec tion in dogs.