The European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) treatment algorithm recommends intra-articular (IA) hyaluronic acid (HA) for management of knee osteoarthritis (OA) as second-line treatment in patients who remain symptomatic despite use of non-steroidal anti-inflammatory drugs (NSAIDs). This recommendation is based upon accumulating evidence that IA HA provides a significant benefit in knee OA. There is good evidence that IA HA injections reduce pain and increase function in knee OA, and the benefits are long-lasting as compared with IA corticosteroids. Evidence from real-life studies of repeat courses of IA HA demonstrates an improvement in pain or function lasting up to 40 months (12 months after the last injection cycle), a reduction in use of concomitant analgesia by up to 50%, and suggests that there may be a delay in the need for total knee replacement (TKR) of around 2 years. The clinical benefit of IA HA on knee OA may be 2-fold: (i) mechanical viscosupplementation of the joint (allowing lubrication and shock absorption) and (ii) the re-establishment of joint homeostasis through induction of endogenous HA production, which continues long after the exogenous injection has left the joint. The magnitude of the clinical effect may be different for different HA products, but this has not been proven so far and requires further investigation. IA HA injections are generally considered to be safe, although a slightly higher number of cases of local reactions and post-injection non-septic arthritis has been reported with high molecular weight cross-linked HAs. The use of IA HA in knee OA patients with mild-moderate disease, and for more severe patients wishing to delay TKR surgery, is recommended by the ESCEO task force. Further investigation into the OA patient types most likely to benefit from IA HA is warranted. Viscosupplementation with IA HA is a safe and effective component of the multi-modal management of knee OA.

There is a discrepancy between evidence in support of the widespread use of intra-articular hyaluronic acid (IAHA) to treat knee osteoarthritis (OA) in clinical practice, and the often discordant recommendations from multiple international guideline committees, which requires further investigation. We conducted a literature review to determine the strength of evidence in support of the efficacy and safety of IAHA, from randomized controlled trials and meta-analyses. Our analysis shows that IAHA provides a moderate symptomatic benefit to knee OA patients and without major safety concerns. In fact, IAHA may offer one of the best benefit/risk ratios among pharmacologic options, as measured by improvements in knee OA health outcomes, overall gain in quality-adjusted life years and substantial delays in time to total knee replacement. We advocate for the consideration of recommending IAHA injection as a treatment option in the management of knee OA, tailored by disease stage and patient phenotype. Future research efforts should focus on identification of OA patient subgroups that demonstrate a more robust response to IAHA, determination of long-term effects of repeat IAHA injections on patient-reported outcomes and total knee replacement-sparing effect, further elucidation of disease-modifying effects, and the potential for combination therapy with other pharmacologic and non-pharmacologic therapies to optimize the management of knee OA.

To compare the effects of an intermediate molecular weight (MW) intra-articular hyaluronic acid (HA) with a low MW product on knee osteoarthritis (OA) symptoms. Patients with symptomatic knee OA were enrolled inarandomised, controlled, double-blind, parallel-group, non-inferiority trial with the possibility to shift to superiority. Patients were randomised to GO-ON(MW 800-1500 kD, 25 mg/2.5 ml) or Hyalgan(MW 500-730 kD, 20 mg/2 ml) injected at 3-weekly intervals. The primary outcome was 6-month change in the WOMAC pain subscale (0-100 mm). Sample size was calculated on a non-inferiority margin of 9 mm, lower than the minimum perceptible clinical improvement. Secondary endpoints included OARSI-OMERACT responder rates The intention-to-treat (ITT) and per-protocol (PP) populations consisted of 217 and 209 patients and 171 and 172 patients in the GO-ON and Hyalgan groups, respectively. ITT WOMAC pain of 47.5±1.0(SE) and 48.8±1.0 mm decreased by 22.9±1.4 mm with GO-ON and 18.4±1.5 mm with Hyalgan after 6 months. The primary analysis was conducted in the PP population followed by the ITT population.Mean (95% CI) differences in WOMAC pain change were 5.2 (0.9 to 9.6)mm and 4.5 (0.5 to 8.5)mm, respectively,favouring GO-ON, satisfying the claim for non-inferiority (lower limit>-9 mm) and for statistical superiority (95% CI all>0, p=0.021). Ahigher proportion of OARSI/OMERACT responders was observed with GO-ONthan with Hyalgan (73.3% vs58.4%, p=0.001). Both preparations were well tolerated. Treatment with 3-weekly injections of intermediate MW HA may be superior to low MW HA on knee OA symptoms over 6 months, with similar safety.

Objective To assess the ability of avocado–soybean unsaponifiable—Expanscience (ASU-E) to slow radiographic progression in symptomatic hip osteoarthritis (OA). Methods Prospective, randomised, double blind, parallel group, placebo controlled 3 year trial. Patients with symptomatic (painful ≥1 year, Lequesne Index between 3 and 10) hip OA (American College of Rheumatology criteria) and a minimum joint space width (JSW) of the target hip between 1 and 4 mm on a pelvic radiograph were randomly assigned to 300 mg/day ASU-E or placebo. Standing pelvis, target hip anteroposterior (AP) and oblique views were taken annually. The primary outcome was JSW change at year 3, measured at the narrowest point on pelvic or target hip AP view (manual measure using a 0.1 mm graduated magnifying glass). The full analysis dataset (FAS) included all patients having at least two successive radiographs. An analysis of covariance Mixed Model for Repeated Measurements with Missing at Random (for missing data) was performed to compare adjusted 3 year JSW changes (primary outcome) and the percentages of ‘progressors’ (JSW loss≥0.5 mm) between groups. Results 399 patients were randomised (345 kept in the FAS), aged 62 (35–84) years, 54% women, mean body mass index 27 (SD 4) kg/m², mean symptom duration 4 (SD 5) years, 0–100 normalised Lequesne Index 30 (SD 9) and global pain visual analogue scale 37 (SD 23) mm. Mean baseline JSW was 2.8 (0.9) mm. There was no significant difference on mean JSW loss (−0.638 mm vs −0.672 mm, p=0.72, in the ASU-E and placebo groups, respectively) but there were 20% less progressors in the ASU-E than in the placebo group (40% vs 50%, respectively, p=0.040). No difference was observed on clinical outcomes. Safety was excellent. Conclusions 3 year treatment with ASU-E reduces the percentage of JSW progressors, indicating a potential structure modifying effect in hip OA to be confirmed, and the clinical relevance requires further assessment. Trial registration number on ClinicalTrial.gov NCT01062737