Early morphometric and anisotropic change in periarticular cancellous bonein a model of experimental knee osteoarthritis quantified using microcomputed tomography

Objective. To quantify early stage microstructural changes of periarticular cancellous bone in a canine anterior cruciate ligament transection model f or experimental osteoarthritis. Design. Unilateral transection of the anterior cruciate ligament was perfor med in 10 animals, Bone structure changes were quantified in five animals a t 3-week post-transection and five animals at 12-week post-transection. An additional two non-operated animals were used as controls. Background. Changes in trabecular architecture of the periarticular cancell ous bone in early stage post-traumatic osteoarthritis is not well understoo d. Previous studies have found alterations in bone mineral density in exper imental osteoarthritis suggesting adaptation of the trabecular structure. E arly change of the periarticular bone following a ligament injury may contr ibute to the longterm development of osteoarthritis. Methods. Bone cores from the medial condyles of the femoral and tibial pair s were scanned with a three-dimensional microtomographic system. Structural indices were quantified including bone volume ratio, bone surface ratio, t rabecular thickness, trabecular separation, trabecular number, as well as s tructural anisotropy determined by the mean-intercept-length method. Results. Significant structural changes were observed at 3-week post-transe ction, and were more prominent at 12-week post-transection. These changes w ere accompanied by decreasing anisotropy. Conclusions. Periarticular cancellous bone microstructure is significantly altered in experimental osteoarthritis. These changes occurred as early as 3-week post-transection, and were large at 12-week post-transection.