Changes in the canine femoropatellar joint space in the postsurgical, cruciate-deficient stifle joint

In this study, we investigate the factors that influence changes in articular cartilage thickness in naturally occurring osteoarthritis of the canine stifle joint. Fifty-eight dogs with QA secondary to cranial cruciate ligament deficiency were examined radiographically at 0, 7, and 13 months using 90 degree flexed mediolateral radiographs of both stifle joints. The femoropatellar joint space widths were measured using a computer-assisted video image analysis system. The femoropatellar joint space widths were found to be significantly increased in index joints as compared to contralateral joints. In addition, there was a significant increase in femoropatellar joint space (FPJS) width over the course of the study, particularly between entry and 7 months. Factors that might influence the degree of femoropatellar joint space increase (bodyweight, age, sex, disease duration, radiographic score) were investigated using regression analysis. Body weight at baseline showed a moderate to strong relationship with change in FPJS between 0 and 7 months (Pearson's partial correlation r = 0.417, p = .006). This relationship was less strong for change in femoropatellar joint space between 7 and 13 months (r = 0.324, p = .036).