Improvement of self-reported functional scores and thickening of quadriceps and femoral intercondylar cartilage under ultrasonography after single intra-articular injection of a novel cross-linked hyaluronic acid in the treatment of knee osteoarthritis.

Background: Most studies used hyaluronic acid (HA) requiring 3-5 intra-articular injections (IAJ) for knee osteoarthritis (KOA).

Objective: We evaluated the efficacy of a single IAJ of a novel HA by measuring the thickness of quadriceps and femoral intercondylar cartilage (FIC) under ultrasonography (US) in addition to subjective self-reported measures.

Methods: Forty-nine patients with KOA (Kellgren-Lawrence grades 2-3) received unilateral IAJ of HYAJOINT Plus to the worse knee and were assessed at baseline and 1, 3 and 6-months after IAJ. Outcome measures were the (1) Visual Analog Scale for pain (VAS), (2) Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), (3) Lequesne's Index, (4) single-leg-stance duration (5) thigh circumference, and (6) thickness of quadriceps and FIC under US.

Results: Forty-six patients completed the 6-month-follow-up study. All outcome measures improved significantly after HA injection (p< 0.001). Both VAS and WOMAC-pain subscale scores improved significantly at 1, 3, and 6 months (p< 0.01). The US thickness of the quadriceps and FIC improved significantly at both 3 and 6 months (p< 0.05). The Lequesne's index, single-leg-stance and thigh circumference improved significantly at 6 months (p< 0.01).

Conclusions: HYAJOINT Plus is effective both subjectively and objectively for 6 months and is safe as a treatment for KOA.