Evaluation of effects of intraarticular bisphosphonate injection in experimental temporomandibular joint osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disease that causes changes in cartilage, disc, synovium and subchondral bone which can be seen in all joints such as hands, feet or spine. Temporomandibular joint (TMJ) osteoarthritis (OA) is the most common form of arthritis seen in TMJ. Bisphosphonates (BP) are drugs that have a strong affinity for bone and inhibit bone resorption. In the early stages of OA, increased osteoclast activity results in a decrease in subchondral bone thickness and an increase in the number of subchondral porosity and a loss of integrity and plasticity at the osteochondral junction. Systemic or intraarticular (IA) administration of bisphosphonates is thought to be beneficial in the treatment of OA by reducing subchondral bone resorption and providing chondroprotective effect. In our study, it was aimed to evaluate the effect of IA zoledronic acid (ZA) injection on subchondral bone and cartilage in experimentally TMJ OA in rabbits. Sixteen adult male New Zealand rabbits were randomly divided into two groups as the control group (n = 8) and the experimental group (n = 8). An experimental OA model was created by injecting sodium monoiodoacetate (MIA) into the left TMJ of rabbits in both groups. One month after MIA injection, 0.1 mg of 1A ZA was injected to TMJs of rabbits in the experimental group weekly for four weeks. At the end of the experimental procedure, all rabbits were sacrificed and joint cartilages, osteochondral junction, chondrocyte appearance and subchondral ossification of TMJs were evaluated histopathologically. When the results of the study are evaluated, it was observed that the IA BP injection in the treatment of TMJ OA had a positive effect on joint cartilage, osteochondral junction and chondrocytes, however no statistically significant difference was found (p>0.05). It is concluded that new controlled clinical and animal studies are needed to evaluate the long-term effects, to determine the appropriate doses and to find the effective treatment timing.