The Association between Radiographic Features and the Duration of Effectiveness of a Single Injection of Extended-Release Hyaluronic Acid (HANOX-M-XL) in Patients with Knee Osteoarthritis: Preliminary Results of a Prospective Trial

Background Advanced radiological stage of knee osteoarthritis (OA) is predictive of poor response to viscosupplementation (VS). To date, the impact of x-ray features on the duration of effectiveness (DE) of VS has not been investigated. Objectives To investigate the radiological features associated with DE of VS in patients with knee OA. Methods Cross-sectional study in patients with knee OA treated with 1 injection of cross-linked hyaluronic acid (HA). The primary outcome was DE, self-assessed by the patients in weeks of effectiveness. Radiological features (joint space narrowing-JSN topography and Kellgren-Lawrence [K-L] grade) associated with DE were studied. Results Fifty-one patients-33 females (76 knees)-were analyzed. The average DE was 52.0 (24.7) weeks (range, 13-155 weeks). In the bivariate analysis, DE was 14 weeks longer in those with K-L grades 1 and 2 (62.6 +/- 36.4 weeks) than in those with K-L 3 and 4 (48.9 +/- 18.6) (P = 0.03). DE was not significantly different according to the involved compartment(s). It was significantly longer in men than in women (60 +/- 31.4 vs. 47 +/- 16 weeks; P = 0.035). In multivariate analysis, K-L grade (1-2 vs. 3-4) (P = 0.007), male gender (0.02), and older age (0.04) were independently associated with a longer DE. Conclusion DE of a single injection of extended-release HA is longer in K-L 1-2 than in K-L 3-4 OA knees, regardless of the JSN topography. However, even the patients with more advanced OA benefited from HANOX-M-XL injection for an average duration barely less than 1 year.