Long-Term Outcomes of Single versus Multiple Courses of Viscosupplementation for Osteoarthritic Knee Pain: Real-World, Multi-Practice Experience Over a Six-Year Period

Introduction: Viscosupplementation (VS) is a safe and effective local treatment for osteoarthritis (OA) of the knee. While much research has been completed evaluating its efficacy, comparatively little research has been completed examining the effects of multiple, repeat courses of treatment versus a single course of treatment. Methods: We retrospectively reviewed real-world data from a large cohort of patients receiving treatment for OA of the knee at 16 rehabilitation clinics. Patients were grouped based on whether they received a single course of treatment or multiple courses. Outcomes for this study included pain (measured via the visual analog scale, VAS) and functional ability (measured via the Western Ontario and McMaster Universities Arthritis Index (WOMAC)). Pain and function scores were collected at baseline (prior to treatment administration) and one week following each course of treatment. Results: Patients receiving multiple courses of treatment saw greater improvements than those receiving a single course. For VAS, maximal improvement occurred after the fourth course (66% improvement: 1.7 +/- 1.2 vs 5.0 +/- 2.4 at baseline, p<0.0001). WOMAC scores saw maximal improvement up to the fourth course for all domains (pain: 74%: 2.5 +/- 3.3 vs 9.5 +/- 5.3, p<0.0001; stiffness: 61%: 1.3 +/- 1.0 vs 3.3 +/- 2.0, p<0.0001; function: 66%: 9.5 +/- 7.2 vs 28.3 +/- 14.1, p<0.0001). When scores from multiple courses were averaged, improvements were maintained through the fourth course for VAS (3.4 +/- 2.8) and all WOMAC domains (pain: 6.1 +/- 5.0; stiffness: 3.0 +/- 2.2; function: 23.4 +/- 17.3). Discussion: Our results indicate that multiple courses of treatment are associated with greater improvements than a single course of VS, and that these improvements continue through four courses of treatment.