Effect of boric acid on cartilage formation of osteochondral defects in rabbit knee: An experimental study

The present study aimed to investigate the healing of articular cartilage with boric acid (BA) injection in an experimental cartilage defect model of rabbit knee.

Nine skeletally mature female New Zealand White rabbits were used. The right knees of the rabbits were assigned as the study group and injected with the BA solution and the left knees of the rabbits as the control group. Under anesthesia, a cylindrical full-thickness osteochondral defect (4 mm in diameter and 3 mm in depth) was formed using a drill on the anterior side of the articular surface of the medial femur condyle. The BA solution was administered to the right knees of rabbits in the form of an intra-articular injection (8 mg/kg) for 6 weeks, at the same day and hours each week. The animals were euthanized at the end of the 2nd month.

In both macroscopic evaluation and microscopic evaluation, statistically significant differences were observed in the BA injection group compared with the control group (p<0.05). In the macroscopic examination of the defect area, statistically significant differences were observed between the groups in terms of degree of defect repair, integration to border zone, and macroscopic appearance (p<0.05). The averaged results of all evaluated parameters of the International Cartilage Repair Society visual histological assessment score were better for the BA group.

The healing process of the cartilage injury could be improved by BA injection administration. In future, BA may safely be used as an additional treatment modality in clinical practice to enhance the healing process of cartilage injuries, which are commonly observed orthopedic problem.