Comparative Effectiveness of Lateral Wedge Insoles versus Viscosupplementation in Early Medial Compartment Knee Osteoarthritis: A Prospective Comparative Study

Background: Lateral wedge insoles (LWI) and viscosupplementation (VS; single intra-articular hyaluronic acid injection) are both used for early medial compartment knee osteoarthritis (OA) but are rarely compared head-to-head. Objective: To compare pain and function with LWI versus a single hyaluronic acid injection over 6 months in adults with Kellgren–Lawrence grade 1 and 2 medial knee OA. Study Design: Prospective comparative study with blinded outcome assessment. Methods: Adults aged 40–70 years with Kellgren–Lawrence grade 1 and 2 medial knee OA were consecutively enrolled from a tertiary orthopedic clinic and allocated 1:1 to LWI (7 mm lateral elevation, prescribed 5–10 hours/day) or a single 6 mL hyaluronic acid injection. Visual Analogue Scale for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee Society Score were recorded by blinded assessors at baseline, 6 weeks, 3 months, and 6 months. Results: All 100 participants completed follow-up (no attrition). Groups were comparable at baseline in age, sex, BMI, KL grade, and all outcome measures. Both treatments improved all measures ( P < 0.001). At 6 months, pain relief was greater with LWI (VAS 1.78 ± 0.71 vs. 4.66 ± 0.94; P < 0.001), whereas VS pain scores rebounded from 2.98 ± 0.84 at 3 months to 4.66 ± 0.94 at 6 months. Function improved equally (WOMAC P = 0.533; Knee Society Score P = 0.339). Conclusions: LWI produced more durable pain relief than single-injection VS, with equivalent functional gains—a low-cost, low-risk option, though its open-label design warrants caution. Clinical Relevance Statement: In early medial knee OA, lateral wedge insoles provided pain relief comparable to a hyaluronic acid injection at 3 months and superior at 6 months, supporting orthotic care as an early treatment option.