Does Loading Influence the Severity of Cartilage Degeneration in the Canine Groove-Model of OA?

Many animal models are used to study osteoarthritis (OA). In these models the role of joint loading in the development of CA is not fully understood. We studied the effect of loading on the development of CIA in the canine Groove-model. In ten female beagle dogs OA was induced in one knee according to the Groove-model. The animals were divided in groups with and without forced-loading. Forced-loading was achieved by fixing the contra-lateral limb to the trunk 3 times a week for 4 hours. After 20 weeks joint tissues of all dogs were evaluated. Subjective evaluation revealed less movement with more loading in the forced-loading-group compared to the group without forced-loading. In both groups induction of OA resulted in macroscopical and microscopical CA changes as well as alterations in cartilage metabolism characteristics for OA. Although differences were small, for some parameters they were statistically significant for the forced-loading-group. There were no differences between the contra-lateral healthy joints of both groups. The present study demonstrates that in the Groove-model intensified loading is not a prerequisite for the development of OA, although it adds to some extent to the severity of the OA. (C) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1332-1338, 2009