Purpose of the study: To see if there are any differences in pain relief and complications with intraarticular Knee injection of synthetic and avian Hyaluronic acid products.

Summary: After following the inclusion and exclusion criteria, 130 patients were randomly allocated two groups, receiving either synthetic or avian Hyaluronic acid injections. Patients were explained about the study and consent was sought. They were given Western Ontario and McMaster University [WOMAC] questionnaires to be filled before, 48 hours, 6 weeks and 3 months after the injections. They were examined at 6 weeks, 3 and 6 months post injections.

124 of these patients promptly responded. 68 patients had natural product and 56 patients had synthetic product.

In the natural injection group of 68 patients, 57 had pain relief at 3 months and 20 of these continued to have relief at 6 months.

In the synthetic injection group of 56 patients, 48 had pain relief at 3 months and 28 of these continued to have relief at 6 months.

No complications were noted in either of the groups.

Difference of WOMAC scores were done at 6weeks and 3 months for each group. The p value of this difference of scores was 0.12 at 6 weeks and 0.92 at 3 months showing no significant difference. The 95% confidence intervals [avian vs synthetic] at 6weeks were −0.8 to 7.2 and at 3 months were −3.8 to 4.2. The p value of clinical examination at 6 months was 0.043 showing significance.

Conclusion: Synthetic injections are significantly more effective, economical and equally safe as avian injections.