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Significant individual improvements in knee pain, stiffness, and function in patients with osteoarthritis treated with viscosupplementation injections compared with intra-articular corticosteroids or placebo has prompted the American Medical Society for Sports Medicine (AMSSM) to recommend this treatment for knee osteoarthritis. The research is published in the Clinical Journal of Sport Medicine.
While previous studies have found inconclusive or varied evidence on the effectiveness of viscosupplementation injections (hyaluronic acid [HA]), research conducted by Thomas Trojian, MD, from the Division of Sports Medicine at Drexel University College of Medicine and colleagues found that patients treated with HA injections had a 15% and 11% greater chance of achieving Osteoarthritis Research Society International (OARSI) responder status than did those treated with intra-articular corticosteroid (IAS) or intra-articular placebo (IAP), respectively.
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The study was conducted using the Outcome Measures in Rheumatoid Arthritis Clinical Trials–Osteoarthritis Research Society International (OMERACT-OARSI) criteria, a more relevant method than that used in previous studies, which seeks to identify the proportion of participants who meet preset criteria for response as individuals. The researchers therefore studied the benefit to the individual patient rather than the benefit averaged across the group.
“We do not treat groups of people, we treat individuals,” said Dr Trojian in a press release. “It is important to look at how a person responds to a medication … Using a network meta-analysis, we [were] able to compare the multiple studies done on viscosupplementation and have found that people are more likely to show clinical improvement with viscosupplementation over placebo (saline) and intra-articular steroids. This is different than studies recently published that say the average response differs.”
The researchers also noted that their recommendations differ from previous ones. The American College of Rheumatology makes no recommendations for treating knee osteoarthritis with HA injections in their latest iterations, and the OARSI guidelines rate the benefit from HA as uncertain.
A notable exception is the recent guideline from the American Academy of Orthopaedic Surgeons (AAOS) strongly recommending against HA injections. This guideline is based on the minimum clinically important improvement (MCII) outcome measure, a relatively new measurement that, while representing an effort by investigators to incorporate subjects’ expectations for improvement into the assessment, has been criticized on several accounts and has not been adequately validated for use in isolation to guide clinical decision making.
The researchers note that the AAOS recommendation may be problematic, given that individual patients find benefit from HA injections as demonstrated in their study. “An incorrect recommendation against the use of HA may encourage third-party payers to limit or eliminate reimbursement for HA as a cost-saving measure,” the researchers wrote. It is also possible that given the limited number of nonsurgical treatments available, an absence of HA injections may result in an increase in the number of surgical procedures performed, although the results of a recent meta-analysis of this question were inconclusive.
Based on the results from this analysis, the AMSSM makes the following recommendations and suggestions:
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AMSSM RECOMMENDS viscosupplementation injections for Kellgren and Lawrence (KL) grade II-III knee osteoarthritis in those patients older than age 60 based on HIGH quality evidence demonstrating benefit using OMERACT-OARSI Responder Rating. For those younger than 60 years, however, the evidence should be downgraded due to indirectness.
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AMSSM SUGGESTS viscosupplementation injections for knee osteoarthritis for those under age 60 based on MODERATE quality evidence due to response of treatment in those older than 60 years.
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AMSSM RECOMMENDS clinicians and researchers collect OMERACT-OARSI responder data to track individual response to the viscosupplementation.
The researchers add that each injectable medication they studied may have a different role in treating knee osteoarthritis. IAS injection was superior from 0 to 4 weeks after administration, but HA injection was superior from 4 to 26 weeks. This could mean that IAS may be able to rapidly abort a flare of knee osteoarthritis, while HA injections may be used for longer-term control of baseline symptoms but may not be appropriate for treating acute exacerbations.
The researchers also note that more high-quality studies are needed to address the residual uncertainties of the clinical benefit from HA injection, especially in the active 40- to 60-year age group. Characteristics also need to be identified to predict who might benefit from HA injections.
