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Meta-analysis: Hyaluronan injections superior to corticosteroids in OA treatment
Surgeon reviews benefits, options, properties and treatment applications of hyaluronan injections.
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Given the potentially deadly side effects of NSAIDs and COX-2 inhibitors, hyaluronan injections look more and more attractive for treating osteoarthritis patients.
Among the injections’ attributes: The American College of Rheumatology recommends hyaluronan injections as part of its comprehensive arthritis treatment program. Data suggests that the injections work well. They are approved for use in the hip, ankle and shoulder in Europe. And the FDA is likely to approve hyaluronan for use in the shoulder and hip this year, according to S. David Stulberg, MD, of Northwestern University Hospital in Chicago.
But what are the hyaluronan injection products and how do they differ?
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Source: Stulberg SD |
Stulberg discussed these options and more about hyaluronan injections at the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting. “The guidelines for optimizing treatment and success are, first of all, patient selection, secondly accurate injection and finally integrating it into a comprehensive [exercise] program,” Stulberg said. He cautions not to use hyaluronan in patients with end-stage disease.
In a recent meta-analysis from the Cochrane Collaboration, researchers found that “HA is superior to placebo, it’s more effective than intra-articular corticosteroids and just as good as nonsteroidals,” Stulberg said. “And there was no significant difference in safety noted when hyaluronan, including Synvisc, was compared to either placebo or intra-articular corticosteroids.”
Stulberg also noted findings that initially, hyaluronan and corticosteroids equally affect pain relief, but after 12 weeks, hyaluronan is more effective and offers greater functional gains.
Often, surgeons combine hyaluronan with other forms of appropriate care, including steroids – shown to improve functional outcome at 26 weeks, Stulberg said.
Despite its success, researchers still do not completely understand the mechanism of action for hyaluronan, but they believe the injections work as a pain reduction, inflammatory control or chondroprotective device, Stulberg said.
Important differences exist among hyaluronan injection products in number of injections and suggested pain relief duration.
“The clinical significance of these differences is not 100% known,” Stulberg said. “In general there tends to be an association between molecular weight and the length of time these devices seem to be used.”
Studies suggest three injections for Synvisc (Genzyme Corp.), three to five injections for Hyalgan (FIDIA SpA), five injections for Supartz (Seikagaku Corp.) and three or four for Orthovisc (Anika Therapeutics Inc.), he said.
How long does hyaluronan last?
Studies also suggest that each product provides pain relief, as follows: Synvisc and Supartz, six months; Hyalgan, 60 days to six months; and Orthovisc, 22 weeks.
The hyaluronan’s half-life within the joint, also known as the joint residence time, also differs. For Orthovisc, Supartz and Hyalgan, it is less than one day, Stulberg said. However, Synvisc has a joint residence time of seven days.
“It tends to stick on articular cartilage up to seven days and without further injections is pretty much gone shortly after that,” Stulberg said.
Shelf life degrades
The shelf life of hyaluronan – in particular, non-crosslinked hyaluronans, including Hyalgan, Supartz and Orthovisc – also degrades over time if stored at room temperature.
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Case reports have found a potential pseudoseptic reaction in the form of a painful, warm and swollen knee with hylan G-F 20 only.
However, the reaction is not immunogenic and is somewhat rare – estimated at one in 500 to 1000 injections, Stulberg said.
To treat, “It has to be differentiated from infection,” he said. “You have to aspirate the knee. If you’re sure it’s not infection, you can treat it with corticosteroids.”
Stulberg said studies have found no statistical difference in complications between the first and second treatment rounds. However, he suggests switching to Hyalgan for future injections.
“The patients request this therapy, and if you’re not going to give it, they’ll go somewhere to get it,” Stulberg said. “The treatment is a financially viable one for a practice if it’s managed correctly.”
For more information:
- Brander V, Stulberg SD. The injectables: Palliation and promise. #66. Presented at the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting. May 21-24, 2006. Las Vegas.