Mémoires du département kinésithérapie

IESCA, Haute Ecole Charleroi Europe

2007-2008

IMPACT ON SUBCHONDRAL BONE OF OSTEOARTHRITIS DEVELOPMENT AND EFFECT OF CALCITONIN: EXPERIMENTAL STUDY ON CANINE SUBJECTS

Caroline Debast

Aim:

To assess the thickness and density of the tibial chondro-osseous junction (COJ) in a model of experimental canine osteoarthritis (OA) and to determine to what extent calcitonin (CT) can change these parameters.

Methods:

After anterior cruciate ligament transection (ACLT) in the right knee, 12 dogs received a daily nasal spray delivering either 400 U of CT (n=6) or a placebo (n=6). The animals were killed 84 days after surgery. Proximal tibiae of each dog were stained with basic fuchsin and embedded in methacrylate. Bone mineral density (BMD) of the medial and lateral COJ was measured in each plateau by pQCT. Undecalcified 80-mm-thick coronal sections through the tibiae were microradiographed. The thickness of calcified cartilage (CC) as well as the bone volume fraction (BVF) of the subchondral bone plate were measured in the microradiographs and the sections. The quantitative data were analysed with two-tailed t-tests. A p value < 0.05 was considered statistically significant.

Results:

All operated knees presented macroscopic signs of OA, though less extensive in the CT group than in the placebo one. In the histologic sections, the comparison between operated and non-operated tibiae for the medial plateau of the placebo-treated group shows a significant decrease in thickness of the CC. No difference in thickness of CC between medial and lateral tibial plateau could be observed and no effect of the CT treatment could be identified in a significant way. In both groups, BVF and BMD show a significant difference between lateral and medial tibial plateau for the operated and non-operated tibia. In the placebo-treated group, BMD of the medial COJ was significantly lower in the operated tibia than in the non-operated one, whereas this difference was not found in the CT-treated dogs.

Conclusions:

Compared with the findings from other studies, it appears that the studied tibial plateaus affected by OA following ACLT operation correspond to an early stage of the disease. At this stage, the decrease in CC thickness and BMD in the medial subchondral bone plate can be considered the effect of the ACLT and was not observed with CT treatment. These data suggest that ACLT induces some early increase of remodeling in the medial COJ, leading to thinning of CC and decrease of BMD in the medial plateau. As these modifications do not appear under CT treatment, which also reduces the OA manifestations, they likely contribute, at least partly, to OA development.