Hyaluronic acid versus saline intra-articular injections for amelioration of chronic knee osteoarthritis: A canine model.

The objective of this study was to assess the safety and efficacy of intra-articular injections of hyaluronic acid (HA) versus saline for symptomatic treatment of osteoarthritis (OA). Twenty-five adult purpose-bred dogs underwent meniscal release of one knee. Clinical, arthroscopic, and radiographic signs of OA were confirmed in all dogs prior to treatment. Dogs were randomized into five groups: HA-1 (n = 5), HA-3 (n = 5), HA-5 (n = 5), Saline-1 (n = 5), and Saline-3 (n = 5). Each dog received intra-articular injections of the respective substance into the affected knee at the pre-determined time points. Dogs were assessed for heat, swelling, and erythema after each injection and for lameness, pain, effusion, range of motion, kinetics, radiographic OA scoring, and arthroscopic scoring prior to treatment and for 6 months after injection. Dogs were then humanely euthanatized and the knees assessed grossly and histologically. Only mild heat, swelling, and/or erythema were noted in some dogs following injection and resolved within 1 week. Dogs treated with HA-1, HA-3, and HA-5 were significantly (p < 0.05) better than dogs treated with Saline-1 and Saline-3 at the 4, 8, and 12 week time points based on at least one outcome measure. OA severity was not significantly different among groups at any time point, but increased in severity over time in all groups. Gross and histologic OA scores were not significantly different among groups. These data suggest the three HA injection protocols were safe, superior to saline for short-term amelioration of symptoms associated with chronic OA, and can be translated to human OA treatment.