Osteoarthritis of the trapeziometacarpal joint (TMJ), also called rhizarthrosis is a common disease, mostly affecting post-menopausal women. Intra-articular therapy with hyaluronic acid (HA) was usually recommended as a second-line treatment after failure of non-pharmacological modalities, only in early stages of the disease .Aim of the present observational, retrospective, comparative study is the assessment of the efficacy and tolerability of i.a. injections of an hybrid HA formulation (Synovial H-L®) in comparison to triamcinolone in patients with TMJ Osteoarthritis (OA). We are analyzing the records collected in the departmental archives of outpatients affected by TMJ OA, according to the ACR criteria for the classification for hand OA and who were treated with i.a. Sinovial H-L or triamcinolone acetonide from December 1st, 2015 to December 1st 2016.The patient's assessment of spontaneous hand pain on a 0-100 mm VAS with 0 representing the absence of pain and the FIHOA score validated in Italian language were routinely recorded and documented in our centre prior to the injections (T0), at the time of the second i.a. administration (T1), after one month (T2) and after 3 (T3) and 6 months (T4) following the i.a. therapy.

The primary outcome criteria of our study is the change of VAS and FIHOA from baseline to the end of treatment. Furthermore, we chose as secondary outcomes the duration of morning stiffness, the Italian version of Health Assessment Questionnaire (HAQ) and the validated Italian version of the Medical Outcomes Study 36-Item Short Form (SF-36) routinary registered in our medical record before the i.a. therapy, at the end of the treatment and after 1, 3 and 6 months.

The chi square test, t test or Kruskal-Wallis test, as appropriated, will be used to evaluate differences between groups before i.a. treatment the clinical and demographical data.

Mixed-effects linear regression models will be used to evaluate temporal trends and differences in the two groups for specific outcomes: VAS pain, VAS stiffness, FIHOA and PCS and MCS from SF-36 questionnaires. In these types of statistical models, the effects of the covariates and their standard errors are correctly estimated taking into account the hierarchical structure of the data (i.e., patients and visits). For the compute of SF-36s Z score will be used mean and SD of U.S. general population. Data analysis will be performed using Stata vers 13.0 software. Descriptive statistics will be used to summarize data as frequencies (categorical variables) or mean +/-SD (continuous variables) as appropriate. P values <0.05 is considered statistically significant.

Inclusion Criteria:

• clinical symptoms in the treated thumb for at least 3 months prior to the beginning of i.a. treatment with at least 30 mm on a 0-100 Visual Analogue Scale (VAS) and a Functional Index for Hand OA (FIHOA) score of at least 6
• radiographic evidence of TMJ OA within the previous 6 months with a radiological score of II-III (using the Kellgren method)

Exclusion Criteria:

• any inflammatory joint disease
• septic arthritis
• major trauma
• prior surgery of the hand, wrist, and elbow
• coagulation disorders
• severe comorbidity
• past therapy with chondroitin sulfate, glucosamine, diacerein, steroids by any route of administration
• i.a. injection of any joint with corticosteroids or HA during the previous 6 months

100 patients of both sex affected by TMJ OA