Non-Inferiority of a Single Injection of Sodium Hyaluronate Plus Sorbitol to Hylan G-F20: A 6-Month Randomized Controlled Trial

Advances in viscosupplementation and tribosupplementation for early-stage osteoarthritis therapy

Joint kinematic instability, arising from congenital or acquired musculoskeletal pathoanatomy or from imbalances in anabolism and catabolism induced by pathophysiological factors, leads to deterioration of the composition, structure and function of cartilage and, ultimately, progression to osteoarthritis (OA). Alongside articular cartilage degeneration, synovial fluid lubricity decreases in OA owing to a reduction in the concentration and molecular weight of hyaluronic acid and surface-active mucinous glycoproteins that form a lubricating film over the articulating joint surfaces. Minimizing friction between articulating joint surfaces by lubrication is fundamental for decreasing hyaline cartilage wear and for maintaining the function of synovial joints. Augmentation with highly viscous supplements (that is, viscosupplementation) offers one approach to re-establishing the rheological and tribological properties of synovial fluid in OA. However, this approach has varied clinical outcomes owing to limited intra-articular residence time and ineffective mechanisms of chondroprotection. This Review discusses normal hyaline cartilage function and lubrication and examines the advantages and disadvantages of various strategies for restoring normal joint lubrication. These strategies include contemporary viscosupplements that contain antioxidants, anti-inflammatory drugs or platelet-rich plasma and new synthetic synovial fluid additives and cartilage matrix enhancers. Advanced biomimetic tribosupplements offer promise for mitigating cartilage wear, restoring joint function and, ultimately, improving patient care.

Large Variations in Resistance to Degradation between Hyaluronic Acid Viscosupplements: A Comparative Rheological Study

AIM

To compare the resistance to degradation of linear and cross-linked viscosupplements using a rheological model combining mechanical and oxidative stresses, mimicking what happens inside the joint following HA injection.

METHODS

The rheological properties of 8 HAs were measured using a stress-imposed Rheometer DHR3. Strain sweeps were carried out to evaluate the rheological properties at rest from 0.001 to 3000% at a frequency of 1 Hz. The complex modulus G*, in Pa, and the phase tangent tan δ, dimensionless, in the linear viscoelastic domain (LVED) were extracted. The oxidation tests were conducted by exposing the product to H2O2 for 30 minutes. The effect of oxidation was evaluated by measuring variations of G* and tan δ, using an oscillation time sweep. Those tests were carried out at a frequency of 1 Hz and at 1% strain in the LVED.

RESULTS

At rest, the different samples exhibited various viscous behaviors. During mixing process, G* decreased from -6.4% to -31.3%. G* of low-molecular-weight HAs decreased more than that of medium molecular weight (MW) and cross-linked products. After oxidative stress, G* variation ranged from -10.1% to -46.3%. Cross-linked HAs and those containing mannitol resisted the best to degradation.

CONCLUSIONS

We showed large variations in resistance to degradation between viscosupplements. The duration of effectiveness of these products deserves to be compared in randomized clinical studies.

Is the Rate of Responders to Hyaluronic Acid Injection for Patients with Knee Osteoarthritis Stable Over Time? Post hoc Analyses of a 6-Month Follow-Up Study

INTRODUCTION

Recently, a study showing the non-inferiority of a single injection of sodium hyaluronate plus sorbitol (Synolis VA®) compared to hylan G-F20 (Synvisc-One®) over a 24-week period in patients with knee osteoarthritis was published. The objective of the present study is to assess if a short-term response to a single injection of sodium hyaluronate plus sorbitol can be maintained over a 6 month-period and if the maintenance of the response to treatment is dependent on the functional status at baseline.

METHODS

Responders to treatment at days 28, 84, and 168 were evaluated according to the responder criteria proposed by the OMERACT-OARSI. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to assess functional status at baseline. All analyses were adjusted for age, gender, BMI, and baseline WOMAC total score using data from the intention-to-treat (ITT) population.

RESULTS

Out of the 96 patients included in the study who were receiving Synolis VA®, 59.38% were responders at day 28 according to the OMERACT/OARSI responder criteria, 59.78% at day 84, and 64.52% at day 168. Among the responders at D28, the probability of being responder at D84 and D168 was significantly higher than among non-responders, with corresponding odds ratio (95% CI) of 2.85 (1.07-7.59) and 7.28 (2.53-20.93), respectively. Patients with a poorer physical function at baseline were more likely to respond to the treatment at all time points, compared to those with a better physical function (OR 3.74 [1.37-10.21]).

CONCLUSIONS

An early response of a single injection of sodium hyaluronate plus sorbitol is predictive of long-term response, up to 24 weeks. Patients with a poorer physical function may best benefit from the treatment.

Assessment of the Response Profile to Hyaluronic Acid Plus Sorbitol Injection in Patients with Knee Osteoarthritis: Post-Hoc Analysis of a 6-Month Randomized Controlled Trial

In a previous randomized trial, the non-inferiority of two hyaluronic acid injections (Synolis VA versus Synvisc-One) was assessed in patients with knee OA, with a response rate of 79% for Synolis VA. To assess whether a responder profile could be established for this treatment modality, we used the Synolis VA arm of a published 6-month prospective, multicenter, comparative, randomized, double-blinded trial. At baseline and during the study, pain and function were assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire. Ninety-six subjects from the intention-to-treat trial were included in the analysis. The 6-month change of WOMAC Pain with Synolis VA was not associated with any baseline clinical data. However, the change in WOMAC Function was significantly associated with its baseline level, even after adjustment for potential confounding variables (p = 0.028), i.e., a poorer physical function at baseline was associated with a better response. In conclusion, in addition to the high absolute response rate to Synolis VA, the probability of success is even increased if administered in patients with more limited physical function at baseline. Further research with other potential confounding clinical variables is warranted in order to better applicate the concept of personalized medicine.