Clinical efficacy of 4.4 mL single-dose intra-articular cross-linked hyaluronic acid injection in patients with knee osteoarthritis.

Osteoarthritis (OA) is a degenerative joint disease with increasing prevalence due to population aging. Conservative management of knee OA has traditionally focused on pain control, with intra-articular injections widely used for targeted local therapy. This study evaluated the clinical efficacy of a single 4.4 mL intra-articular injection of cross-linked hyaluronic acid compared with hylastan SGL-80 (4 mL) in patients with knee OA. In this interventional cohort study, 120 patients with grade III knee OA (Outerbridge) were allocated to two groups: Group 1 (UP; n=60) received 4.4 mL cross-linked hyaluronic acid, and Group 2 (Normal; n=60) received hylastan SGL-80/4 mL. All patients followed a 15-day NSAID protocol before injection and had no prior knee injections within 6 months. Outcomes were assessed using VAS, KOOS, and SF-12 at baseline and up to 6 months. Analgesic use, complications, and VAS-KOOS correlations were evaluated. Both groups showed a low complication rate (5%). Pain reduction over 6 months was significantly greater in Group 1 (VAS 6.93 to 2.32) than in Group 2 (6.44 to 3.52; p=0.030). Group 1 demonstrated superior KOOS (p=0.017), SF-12 scores (p=0.021), and reduced anti-inflammatory drug use (p=0.026). VAS-KOOS correlation confirmed greater clinical improvement in Group 1 at 180 days (p=0.031). A single 4.4 mL intra-articular injection of cross-linked hyaluronic acid provides significant and sustained improvement in pain, function, and quality of life in patients with knee OA.