Beyond the Surgical Bill: Pharmacoeconomics and Real-World Utilization Across the Knee Osteoarthritis Care Pathway—A Critical Narrative Review

Background: Knee osteoarthritis (KOA) is often framed as degenerative knee pain, yet behaves as a decades-long care pathway in which medication, injections, comorbidity, productivity loss, and surgery accumulate into a major economic footprint. This critical narrative review synthesizes pharmacoeconomic and pharmacoepidemiologic evidence across that pathway. Methods: Structured source identification was conducted in PubMed, Web of Science, Scopus, and Google Scholar for publications from 2000 to 2026, with citation tracking. Sources were appraised against predefined critical-interpretation domains and mapped narratively rather than pooled; no meta-analysis was performed. Results: Global Burden of Disease 2019 estimates approximately 364.6 million prevalent KOA cases worldwide. Reported evidence indicates that KOA spending is highly concentrated: in a large U.S. claims analysis, knee arthroplasty was performed in approximately 8.8% of patients yet accounted for 61.5% of KOA-related costs, whereas hyaluronic acid represented 3.0% of overall costs; the remaining pathway burden was distributed across years of outpatient care, analgesics, injections, and other nonsurgical utilization. Medication and injection findings were stage- and phenotype-dependent, and observational studies associated opioid exposure with higher fall risk, healthcare utilization, and cost. Intra-articular hyaluronic acid was repeatedly associated with longer time to arthroplasty, interpreted here as an association limited by confounding and immortal-time bias, not a causal effect; platelet-rich plasma value remained price- and durability-sensitive. Conclusions: KOA economics resembles an iceberg—arthroplasty is the visible peak, while the submerged mass is years of pathway-level care. Value-based policy should measure the full pathway, not the surgical episode, using linked claims, registries, patient-reported outcomes, and productivity data.