Long-term clinical benefit and cost-effectiveness of an 8-week multimodal knee osteoarthritis management program incorporating intra-articular sodium hyaluronate (Hyalgan(®)) injections

BACKGROUND: Given the poor long-term effectiveness of focused nonsurgical knee osteoarthritis (OA) treatments, alternative therapies are needed for patients who have unsuccessfully exhausted nonsurgical options. METHODS: A telephone interview was conducted in patients who participated in a single 8-week multimodal knee OA treatment program (mean follow-up: 3.7 years, range: 2.7–4.9 years). The program consisted of five intra-articular knee injections of sodium hyaluronate (Hyalgan(®)), with each injection given 1 week apart, structured physical therapy, knee bracing, and patient education. Clinical outcomes included knee pain severity, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscores, current medication use, and history of total knee arthroplasty. Base-case, subgroup, and sensitivity analyses were conducted to determine the incremental cost-effectiveness ratio (ICER) of the treatment program with comparisons made to historical literature controls undergoing usual care. RESULTS: A total of 218 patients (54%) provided long-term follow-up data. Knee pain severity decreased 60% and WOMAC subscores decreased 33%–42% compared to baseline (all p<0.001). Total knee arthroplasty was performed in 22.8% (81/356) of knees during followup. The treatment program was highly cost-effective compared to usual care with a base-case ICER of $6,000 per quality-adjusted life year (QALY). Results of subgroup analyses, one-way deterministic sensitivity analyses, and second-order probabilistic sensitivity analyses resulted in ICERs ranging from $3,996 to $10,493 per QALY. The percentage of simulations with an ICER below willingness-to-pay limits was 97.2%, 98.9%, and 99.4% for the $50,000, $100,000, and $150,000 per QALY thresholds, respectively. CONCLUSION: Participation in a single 8-week knee OA treatment program, which included one cycle of five intra-articular knee injections of sodium hyaluronate given at weekly intervals, is highly cost-effective and provides clinically meaningful reductions in patient symptoms that are maintained over 3.7 years mean follow-up.