Objectives: Hyaluronic acid (HA) is used in osteoarthritis especially for the control of pain. In this animal study, we investigated the effects of HA on the early stage of osteoarthritis.

Methods: The experimental osteoarthritis model was constituted on 10 rabbits by the way of anterior cruciate ligament transection. In HA group, HA was injected 0.6 ml (15mg/ml) dosage per week for 3 weeks in right knees of ten rabbits and in SF group, saline was injected 0.6 ml dosage per week for 3 weeks in left knees of rabbits. Because three rabbits died in experimental period, fourteen knees of seven rabbits were taken into account for the study. The knees of rabbits, which were sacrified at 12th weeks after index operation, were measured according to cartilage area and Mankin scale.

Results: The mean cartilage area of HA and SF groups were measured 1.097 mm2 and 0.477 mm2, respectively. The difference of mean cartilage area between HA and SF groups was statistically significant (p< 0.05). According to Mankin scale, the mean total point of scale was measured 3.57 in HA group and 11.14 in SF group and the difference between mean total points of groups was significant (p< 0.05). Although, there is no significant difference in cellular abnormality, matrix staining, and tidemark continuity criteries of scale, we found the significant difference between total point and structure of cartilage criteria of scale.

Conclusions: HA has a retarder effect on progression of cartilage injury in early stage osteoarthritis.