ANESTHESIA/FACIAL PAIN J Oral Maxillofac Surg 70:2048-2056, 2012 Treatment Effectiveness of Arthrocentesis Plus Hyaluronic Acid Injections in Different Age Groups of Patients With Temporomandibular Joint Osteoarthritis Luca Guarda-Nardini, MD, DDS,* Marco Olivo, MD,† Giuseppe Ferronato, MD, DDS,‡ Luigi Salmaso, PhD, § Stefano Bonnini, PhD,  and Daniele Manfredini, DDS, PhD¶ Purpose: To investigate for treatment effectiveness in different age groups of patients with temporoman- dibular joint osteoarthritis who underwent a cycle of 5 weekly arthrocenteses plus hyaluronic acid injections. Materials and Methods: We implemented a retrospective study on 76 patients followed up for 1 year. Outcome variables were pain levels at rest and during chewing, subjective masticatory efficiency, functional limitation, perceived efficacy, and jaw range of motion. Three age groups of patients were identified, and treatment effectiveness was compared among groups by means of a multistrata permutation test. Results: All the partial P values of the subtests related to the age groups, adjusted according to the close testing method for controlling multiplicity, were significant: P = .009 (aged 45 years), P = .001 (aged 45-65 years), and P = .001 (aged 65 years). For the younger age group, the treatment had a significant effect only on the pain at mastication and on the subjective efficacy. For the other age groups, the treatment effectiveness was evident with regard to almost all the considered symptoms. Conclusions: Our findings suggested that the treatment protocol was more effective in patients older than 45 years, thus having important clinical implications regarding attempts to define tailored treatment protocols for patients with temporomandibular disorders. © 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2048-2056, 2012 Hyaluronic acid (HA) is a fundamental component for normal joints’ lubrication effect, so exogenous visco- supplementation was hypothesized to have a positive effect on temporomandibular joint (TMJ) disorders. 1 Some early studies supported the efficacy of HA in- jections to treat TMJ internal derangements, 2-4 but more recent evidence suggested that it may be effec- tive in inflammatory-degenerative disorders as well, especially if combined with a thorough joint lavage. 5-8 Such findings allowed extending the indications for TMJ HA injections to a wider population of temporo- mandibular disorder (TMD) patients, especially in terms of age range, because a higher age of onset is recognized for inflammatory-degenerative disorders with respect to other forms of TMD. 9-11 Investigations of patients with TMJ osteoarthritis suggested that sub- jects aged up to 80 years may benefit from a treatment protocol providing arthrocentesis plus HA injec- *Visiting Professor and Responsible, TMD Clinic, Department of Maxillofacial Surgery, University of Padova, Padua, Italy. †Post-Graduate Student, TMD Clinic, Department of Maxillofacial Surgery, University of Padova, Padua, Italy. ‡Professor, TMD Clinic, Department of Maxillofacial Surgery, University of Padova, Padua, Italy. §Professor, Department of Management and Engineering, Univer- sity of Padova, Padua, Italy. Assistant Professor, Department of Economics and Management, University of Ferrara, Ferrara, Italy. ¶Visiting Professor, TMD Clinic, Department of Maxillofacial Surgery, University of Padova, Padua, Italy. Conflict of Interest Disclosures: None of the authors reported any disclosures. Address correspondence and reprint requests to Dr Manfredini: Viale XX Settembre 298, 54033 Marina di Carrara (MS), Italy; e-mail: daniele.manfredini@tin.it © 2012 American Association of Oral and Maxillofacial Surgeons 0278-2391/12/7009-0$36.00/0 http://dx.doi.org/10.1016/j.joms.2012.05.018 2048