The canine bilateral groove model of osteoarthritis.

In studies aimed at local treatment of experimental osteoarthritis (OA) it is optimal to have an internal (untreated) OA control. Such an approach excludes interanimal variation, and allows paired statistical evaluation of treatment efficacy. For this purpose, we developed and characterized a bilateral version of the canine Groove model. We hypothesized that the bilateral version of the canine Groove model would show consistent and clear development of features of OA similar to those found in the unilateral version. In six Beagle dogs, grooves were surgically made in the articular cartilage of the femoral condyles of both knee joints. Six additional dogs underwent bilateral sham surgery. The degree of OA was quantified 20 weeks after surgery and was compared in retrospect to 23 animals that undergone the same procedure in a single knee joint with the contralateral knee serving as a non-OA control. Bilateral groove surgery resulted in OA. This was based on the observed ineffective repair response in which an increase in proteoglycan synthesis, a diminished retention of these newly formed proteoglycans, and an enhanced loss of resident proteoglycans resulted in a decreased cartilage proteoglycan content. These biochemical effects were corroborated by clear histological features of OA. All these effects were found in femor as well as in the (surgically untouched) tibia. Interestingly, features of OA were slightly more severe in the bilateral model than in the unilateral variant. The bilateral canine Groove model showed consistent and clear development of features of OA, comparable to the unilateral model.