Therapeutic Effects of Mesenchymal Stem Cells and Hyaluronic Acid Injection on Osteochondral Defects in Rabbits' Knees

PURPOSE To evaluate the treatment results of intraarticular injection according to the frequency of hyaluronic acid with mesenchymal stem cells on the osteochondral defect of rabbits' medial femoral condyles. MATERIALS AND METHODS A 5 mm diameter and 4 mm depth osteochondral defect was made on the medial femoral condyles of 18 rabbits, divided into six groups. One week after osteochondral defect, group B was injected intraarticularly with hyaluronic acid (HA), group C with mesenchymal stem cells (MSCs), and group D, E and F with both HA and MSCs. Group E and F received second HA injection a week after. Further, group F received third HA injection in the third week. RESULTS In a macroscopic evaluation, groups B (6; range, 5-8), C (6; range, 6-7), D (7; range, 6-7), E (6.5; range, 6-8) and F (7.5; range, 6-8) showed statistically significant improvements in osteochondral defect healing, compared with that of group A (4; range, 3-5) (p=0.002). In histological evaluation, groups B (11.5; range, 11-13), C (13; range, 12-18), D (16; range, 13-18), E (17.5; range, 13-20), and F (19.5; range, 12-22) showed statistically significant differences in osteochondral defect healing, compared with group A (8; range, 6-9) (p=0.006). CONCLUSIONS The intraarticular injections of MSCs or HA can play an effective role during the healing osteochondral defects in rabbits.