Introduction: The hyaluronic acid (HA) is a linear and uniform polysaccharide molecule. The main features of HA are the viscosity and high elasticity. NASHA (stabilized non-animal hyaluronic acid) technology has been introduced in the field of hyaluronic acid to provide an excellent safety profile, high strength and longer lasting.

Objectives: To compare the effectiveness of a unique infiltration of NASHA HA in patients undergoing arthroscopy with Wilkes stages II and stages III–IV.

Material and methods: In our department, since 2012, we have performed 40 bilateral arthroscopies in 40 patients, 80 TMJ treated with non-invasive procedure. We injected HA in 71 joints. Wilkes stage III-IV was founded in 11 joints (27%).Stage II was founded in 29 joints. We compare that group of patients with 40 patients undergoing 40 bilateral arthroscopies in 2011, where HA was not used. The postoperative study consists in the analysis of pain with VAS (visual analogue scale) and the mouth aperture, measured in mm. The follow-up period is 12 months.

Conclusion: The HA infiltrated after arthroscopy improved mouth opening and pain, but with no statistically significant difference. The advantages of this technique are its simplicity, biocompatibility, tissue lubrication, maintains the integrity, motility and cell protection.