The Biomechanical Impact Of Hyaluronic Acid In Knee Osteoarthrtis Patients: A Randomized, Double-blind, Placebo-controlled Study.

Abstract

PURPOSE: To determine how Hyaluronic acid (HA) impacts clinical outcomes and gait function in knee osteoarthritis (OA) patients. METHODS: Nineteen mild-moderate knee OA patients were randomized to receive 3 consecutive weekly knee injections of 2ml Suplasyn (20mg HA) or 1.2 ml placebo (P) (0.01mg HA). Clinical outcomes were assessed using the WOMAC OA Index and gait characteristics were determined with GAITRite software. RESULTS: Means and standard deviations are presented thus, Mx (SD). The patient population was 72.21 (6.61) years old, 167.47(9.26) cm tall and weighed 81.54 (12.68) kg. Eight patients received HA and 11 patients received P. Treatment effects were determined by comparing week 1(W1) to week 4(W4) outcomes, using 1-tail Wilcoxon signed-ranks tests for within group, and 1-tail Mann-Whitney tests, for between groups comparison. At W1 the HA groups normal walking velocity (NWV) = 112.17 (19.42) cm/s and fast walking velocity (FWV) = 152.58 (28.48) cm/s. By W4 their NWV = 120.24 (22.14) cm/s (p=.025) and FWV = 157.58 (30.39) cm/s (p=.164). At W1 the P groups NWV = 108.81 (24.55) cm/s and FWV = 141.54 (31.86) cm/s. By W4 their NWV = 117.76 (22.77) cm/s (p=.03) and a FWV = 143.40 (32.05) cm/s (p=.297). No significant difference existed at either W1 or W4 between the two groups regarding both NWV and FWV (p>.05). At W1 WOMAC pain, stiffness, and function scores for the HA group were 11.25 (4.17), 5.75 (1.39), and 42.63 (13.64), respectively, and by W4 were 8.50 (2.98) (p=.008), 4.50 (1.07) (p=.021), and 32.50 (13.18) (p=.014), respectively. For the P group, W1 WOMAC scores for pain, stiffness and function were 11.55 (2.21), 5.73 (1.42), and 45.36 (6.19), respectively, and by W4 were 11.00 (3.13) (p=.297), 5.27 (1.49) (p=.130), and 39.73 (9.32) (p=.038), respectively. The HA group showed greater improvement in WOMAC scores, but they were not significantly different from P scores at W4 for pain (p =.152), stiffness (p =.272), and function (p =.129). CONCLUSIONS: At one week post-treatment modest improvement in clinical symptoms and gait function may be experienced in knee OA patients treated with 3 consecutive HA injections. These improvements may indicate the progressive nature of the onset of HA treatment in knee OA patients, and provide preliminary evidence for greater improvements expected at 3 and 6 months follow up.