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Viscosupplementation for Knee Osteoarthritis FREE

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The full report is titled “Viscosupplementation for Osteoarthritis of the Knee. A Systematic Review and Meta-analysis.” It is in the 7 August 2012 issue of Annals of Internal Medicine (volume 157, pages 180-191). The authors are A.W.S. Rutjes, P. Jüni, B.R. da Costa, S. Trelle, E. Nüesch, and S. Reichenbach.

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Ann Intern Med. 2012;157(3):I-36. doi:10.7326/0003-4819-157-3-201208070-00474
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What is the problem and what is known about it so far?

Knee osteoarthritis is a common condition in which changes in the knee joints lead to pain. Nonsteroidal anti-inflammatory drugs, such as aspirin, ibuprofen, and naproxen, are the most commonly prescribed agents for this condition, but they do not always work and can have adverse effects. An alternative treatment strategy called viscosupplementation uses injections of hyaluronic acid to improve knee function. Hyaluronic acid occurs naturally in the joint fluid and acts as a lubricant and shock absorber, but people with osteoarthritis have less-than-normal amounts of it in their joints.

Why did the researchers do this particular study?

To summarize information about the efficacy and adverse effects of viscosupplementation for knee osteoarthritis.

Who was studied?

Adults with symptomatic knee osteoarthritis who participated in 89 trials of viscosupplementation.

How was the study done?

The authors reviewed clinical trials that randomly assigned adults with symptomatic knee osteoarthritis to receive viscosupplementation or a “control” intervention. The authors used a statistical method called meta-analysis to combine the results of the separate studies to estimate the effect of the therapy on knee pain intensity and physical function. They also used meta-analysis to estimate the safety of the therapy, including the occurrence of “flare-ups” (a hot, painful, swollen knee within 24 to 72 hours after an injection) and effusions (excessive joint fluid inside the treated knee after an injection).

What did the researchers find?

The authors identified 177 reports describing 89 trials in 12,667 patients with knee osteoarthritis. When combined and analyzed, large, high-quality studies suggested that viscosupplementation had a small, clinically irrelevant effect on pain and no effect on function. Conversely, the authors found an association between viscosupplementation and an increase in adverse events, including flare-ups and effusions, and also life-threatening events or events resulting in hospitalization or disability.

What were the limitations of the study?

The analysis was limited by the poor quality of many of the trials. In particular, many did not provide adequate data on adverse events.

What are the implications of the study?

Viscosupplementation may provide little if no pain relief or function improvement in patients with symptomatic knee osteoarthritis. It also seems to increase the risk for adverse events. On the basis of these findings, the authors discourage the use of viscosupplementation for knee osteoarthritis.

This article was published at www.annals.org on 12 June 2012.





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Submit a Comment/Letter
Viscosupplementation for Osteoarthritis of the Knee – Rutjes, et al - Comments
Posted on August 16, 2012
Suresh Aravind, MD, MBA, Brad Bisson, MPH
DePuy Mitek, a Johnson & Johnson Company
Conflict of Interest: DePuy Mitek, Distributor of Orthovisc
Dear Editors,The data and conclusions of the recent meta-analysis (August 7th, 2012) by Rutjes et al on the treatment of Osteoarthritis with viscosupplementations, raise several questions. From the efficacy standpoint, we expected the authors' summary of efficacy analyses across 71 studies to provide evidence of the efficacy of HA across patient populations. In particular, out of 69 studies with reported effect sizes, 60 (87%) showed an effect < 0 (favoring HA), and 49 (71%) showed an effect size < -0.176 (equivalent to a difference of 0.44 cm, with an assumed SD of 2.5 cm). In addition, the authors used a clinically importance difference between the treated group and the control groups of 0.9 cm on a 10 cm scale to assesses the efficacy of viscosupplementation. This cutoff is very strict given the difference between placebo and various proven first and second line treatments for osteoarthritis ranged from 0.44 cm to a 0.65 cm. These values represent the incremental and meaningful benefit of a therapy after subtracting the placebo and other non-specific effects [1]. From the safety standpoint, the Serious Adverse Events (SAEs) listed as concerns, involve disparate body systems, unique patho-physiologies and appear unrelated to each other mechanistically. It is unclear how local intra-articular injections of HAs can be attributed to such a diverse set of SAEs (such as cancer, GI, Cardiovascular) linked to different body systems. While an increase in reported adverse events is apparent, statistically, in the absence of a plausible biological mechanism that could generate these events, some form of biased ascertainment in reporting cannot be ruled out. Moreover, communication with Dr. Baraf (author of the study in Supplement 14 SAE review which contributed 4 of the 6 cancers cases referenced in the meta-analysis), indicate that of the 4 subjects with cancers (breast, prostate, squamous and melanoma) discovered within just 16-74 days post treatment, none were judged by investigators to be related to study treatment. Post marketing safety surveillance data from over 5 million injections of ORTHOVISC® worldwide in patients with osteoarthritis has shown no signals or trends suggestive of such treatment related serious adverse events. We believe that this meta-analysis evidence citing concerns over safety and efficacy from the use of viscosupplementations, does not address the causality or mechanisms of the SAEs, does not reflect the findings from other Level 1 meta-analyses, and has methodological challenges that could affect the conclusions and current treatment paradigm.References1. Dworkin RH, Turk DC, McDermott MP, Peirce-Sandner S, Burke LB, Cowan P et al. Interpreting the clinical importance of group differences in chronic pain clinical trials: IMMPACT recommendations. Pain. 2009;146:238-44.
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