A retrospective analysis of outcomes in patients with temporomandibular joint osteoarthritis (TMJ OA) who underwent a cycle of five weekly arthrocenteses plus hyaluronic acid (HA) injections suggests that this approach may be more effective in patients older than 45 years than in younger patients, Luca Guarda-Nardini, MD, DDS, from the TMD Clinic, Department of Maxillofacial Surgery, University of Padova, Padua, Italy, and colleagues report in an article published in the September issue of the Journal of Oral and Maxillofacial Surgery.

Senior author Daniele Manfredini, DDS, PhD, also from the TMD Clinic in the Department of Maxillofacial Surgery, told Medscape Medical News, "The key problem is the diagnosis. From a clinical viewpoint, and seeing them within a broader framework of the [temporomandibular disease (TMD)] practice and literature, our findings suggest that symptoms of younger subjects are likely to be unrelated to osteoarthritis, despite the similar clinical and radiographic findings."

The researchers analyzed retrospective data on 76 patients who were followed up for one year. The main outcome variables were pain at rest and during chewing, subjective masticatory efficiency, functional limitation, perceived efficacy, and jaw range of motion.

Interest in HA for TMJ is based not only on possible lubrication effects but also on efficacy in inflammatory-degenerative disorders. The researchers examined efficacy in relation to patient age because of the higher age of onset associated with inflammatory-degenerative disorders than with other forms of TMD.

The analysis showed that for patients younger than 45 years, arthrocentesis plus HA injection significantly improved only pain at mastication and subjective efficacy. For patients older than 45 years, arthrocentesis plus HA injection improved all of the treatment outcomes.

The authors write, "In general, this investigation provided data that may be useful in the treatment decision planning at the individual level, suggesting that a cycle of TMJ arthrocenteses plus HA injections to manage symptoms of TMJ osteoarthritis is less indicated for subjects aged younger than 45 years than for older patients."

Is the Benefit From Arthrocentesis Alone? Controlled Trials Needed

Tore Bjornland, MD, who reviewed the study for Medscape Medical News, said, "I am not really convinced by these data. I have always wondered why they used five injections, and have never seen any rationale for that." Dr. Bjornland, who is from the Department of Oral Surgery and Oral Medicine, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, Norway, said that prospective, controlled studies would be required to rule out the possibility that the improvements observed were the result of the arthrocentesis alone, and that these should include the use of arthrocentesis with and without application of medications. Dr. Bjornland has also studied sodium hyaluronate injection in treatment of TMJ OA.

Dr. Bjornland added, "I really think that arthrocentesis is an important treatment in patients with TMJ osteoarthritis, and maybe also in other joint diseases."

Dr. Manfredini said, "This study is part of ongoing research aiming to identify prognostic factors and to tailor individual treatments, possibly by a progressive reduction of the number of injections. Indeed, you must consider that, for a small joint like the TMJ, the five-injections protocol is very invasive. We are currently testing higher [medium]–molecular weight HA to try reducing the invasiveness of the treatment. With this in mind, our findings suggest that in younger subjects, the use of HA injections is less indicated than in older subjects."

Dr. Manfredini also said that patient selection is likely to remain a challenge. "The real problem is that the expression of pain symptoms is always the result of a combination of factors, in which the imaging picture is often poorly predictive of the treatment needs. Also, studies on the HA and joint remodeling are lacking. At the moment, my strong clinical suggestion is to use the cycle of HA injections in older patients with severe clinical symptoms (pain lasting for months) and joint degeneration, in combination with strong counseling."

The authors and Dr. Bjornland have disclosed no relevant financial relationships.

J Oral Maxillofac Surg. 2012;70:2048-2056. Abstract

Janis C. Kelly • Medscape Medical News © 2012 WebMD, LLC