MACROSCOPIC ANALYSES OF THE EFFECTS OF HYALURONATES AND CORTICOSTEROIDS ON INDUCED OSTEOARTHRITIS IN RABBITS' KNEES.

Objective: To evaluate the effects of intra-articular injections of corticosteroids, native hyaluronic acid and branched-chain hyaluronic acid in experimentally-induced osteoarthrosis.

Methods: 44 rabbits underwent anterior cruciate ligament resection and were then divided into four groups of eleven. Group 1: one intra-articular injection of saline solution per week, for three weeks; Group 2: three injections (one per week) of native hyaluronic acid; Group 3: three injections (one per week) of branched-chain hyaluronic acid; Group 4: two injections of betamethasone with an interval of three weeks. The cartilage of the tibial plateaus was evaluated macroscopically twelve weeks after surgery. Changes to the joint surface were graded as follows: Grade 0: smooth joint surface without relief changes; Grade 1: rough surface without any depressions; Grade 2: similar to grade 1, but with depressions on the joint surface; and Grade 3: subchondral bone exposure. The statistical analysis consisted of the use of Student's t test, chi-square test and analysis of variance (ANOVA). The significance level used was 5%.

Results: A statistical difference was found between the control group and the three study groups 2, 3, 4 in relation to the development and severity of arthrosis. However, there was no difference between the groups regarding the drugs studied.

Conclusion: A similar degree of attenuation of the osteoarthrosis process in the rabbits' knees was found with the use of intra-articular injections of low-molecular-weight and high-molecular-weight glycosaminoglycans, and the corticosteroid betamethasone, compared with placebo.