Hyaluronan applied into the joint is not effective in knee osteoarthritis.

Osteoarthritis (OA), or osteoarthritis, which is more commonly used (but not true) among the people, is one of the most common reasons for referral to rheumatology specialists. According to a study conducted in the USA, 6% of individuals over the age of 30 are affected by OA involving the knee joint, and this rate rises to 40% in individuals over the age of 70. Although the incidence of osteoarthritis is high enough to cause it to be accepted as a public health problem, what can be done for the treatment of the disease other than surgical intervention (prosthetic surgery) is quite limited. Drug applications into the knee joint are one of the non-surgical treatment options. Popular but controversial among intra-articular applications is the drug called hyaluronan (Hyalgan, Viscoseal, Synvisc, Orthovisc). Hyaluronan is actually one of the molecules found in normal joint fluid and cartilage, providing the strength and elasticity of the cartilage, and protecting the joint surfaces. The amount of hyaluronan does not decrease in osteoarthritis, but its structure is deteriorated. The claimed effect of this drug is that the external application of this molecule to the joint space has positive effects on OA. Despite numerous studies investigating the effectiveness of hyaluronan in OA, is this drug really effective? Is there a patient group in which it is particularly effective? Or how long does the effect last? The answers to such questions are still far from being satisfactory. This is why new studies can still find their place in rheumatology journals.
The results of a multicenter study conducted in the Netherlands investigating the effect of hyaluronan in osteoarthritis patients are published in the June issue of the Annals of the Rheumatic Disease. Researchers followed half of 335 patients with knee OA for 1 year (approximately) by applying Hyalgan to the knee joint once a week for 5 weeks, while applying saline (also called diluted saline) to the other half. During the study, patients were not allowed to take painkillers or NSAIDs (anti-inflammatory drugs) other than paracetamol (of course, no study can ethically sanction what anyone will take for 1 year, but if patients take these drugs during the study period, they may be excluded from the study, which in this study this is done). They evaluated the effects of the drug (whether or not the patients benefited from these applications) with many different methods. The common feature of these methods is that they are all evaluations made by the patients.
When we examine the results of the study; At the end of the 3rd month, 67.9% of the patients who were administered hyaluronan responded to the treatment (reduction in their disease-related complaints), while 72.4% of the patients who received placebo responded to the treatment. When patients who responded to treatment in both groups were followed up for a long time, the time taken for the symptoms to relapse (recurrence) in hyaluronan-administered patients was approximately 172 days, while it was approximately 204 days in placebo-administered patients. The longer this period, the more effective that application is, however, in this study, the recurrence time of complaints in both groups was very close to each other. Placebo administration seems to be more effective than hyaluronan, but the difference is not statistically significant.
Long story short, no matter how we evaluate it, hyaluronan does not seem to be more effective than salt water in OA. When the results of this study are evaluated together with the high cost of hyaluronan therapy, it means that this application in OA patients would not make much sense. Of course, until these findings are proven otherwise by a more comprehensive study.