A Cross-Sectional Study of Factors Predicting the Duration of the Efficacy of Viscosupplementation in Knee Osteoarthritis

Background: An advanced radiological stage and obesity are predictive of poorer and shorter responses to viscosupplementation in patients with knee osteoarthritis (OA). Very little is known regarding the impact of other factors such as sport practice, comorbidities, or anatomical features of OA. Methods: This study aimed to investigate patients' and OA characteristics associated with the duration of the effectiveness (DE) of viscosupplementation in patients with knee OA. It was a cross-sectional, single-centre clinical trial in patients with knee OA treated with intra-articular (IA) hyaluronic acid (HA) injection(s) within the previous 3 years. The investigators collected data regarding demographic and radiographic features (Kellgren-Lawrence grade and involved knee compartments), dosing regimen (single or repeat injections), the presence and volume of joint effusion, previous or concomitant IA corticosteroid injection, the number of previous viscosupplementations, and comorbidities. Patients completed a questionnaire including the self-assessment of DE (the number of weeks during which viscosupplementation was effective on symptoms), the activity level (sedentary, active, or athletic), and the level of sport activity (light, moderate, or intensive). Predictors of the DE were studied in bivariate and multivariate analyses. Results: In total, 105 patients (149 knees) were analysed (62% women, mean age 66.1 +/- 13.2 years, mean BMI 27.5 +/- 7.5 kg/m(2)). The mean DE was 48.2 +/- 24.8 weeks. In bivariate analysis, the predictors of a shorter DE were BMI > 27.5 kg/m(2), more than three previous viscosupplementations, Kellgren-Lawrence grade 4, sedentary patients, and multicompartmental involvement. In the multivariate analysis, four independent factors remained associated with a shorter DE: BMI > 27.5 kg/m(2), multicompartmental knee involvement, number of viscosupplementations >3, and sedentary lifestyle. A statistically significant association between a longer DE and arterial hypertension was found, suggesting a beneficial effect of certain antihypertensive medications. Conclusions: This study confirms that being overweight significantly reduces the duration of the effectiveness of viscosupplementation. It also shows that viscosupplementation is more lastingly effective in unicompartmental OA and among active or athletic patients. The duration of effectiveness decreases when the treatment is repeated more than three times.