SAT0581 Predictive factors of response to a single injection of mannitol-modified cross-linked hyaluronic acid (HANOX-M-XL) in patients with trapeziometacarpal osteoarthritis. results of a multicentre prospective open-label pilot study (instinct trial). (12th June 2018) - Dauvissat, J.
Abstract : Background: Viscosupplementation is likely effective to alleviate pain and improve function in patients suffering from rhizarthrosis. However no study has been focused on the predictors of efficacy of the treatment. Objectives: To search predictive factors of success or failure 3 months after a single intra-articular injection of a mannitol-modified hyaluronic acid (HA) viscosupplement, in patients suffering from trapeziometacarpal (TMC) osteoarthritis (OA). Methods: Patients with symptomatic TMC OA were included in a 3 month prospective multicentre open-label trial. To be included in the study patients must have symptomatic TMC OA, not adequately relieved by analgesics/NSAIDs therapy and/or by the use of a thumb splint. Before treatment all patients must have had plain radiographs with the Kapandji incidences, for the Dell radiological grade assessment. (1 to 4). Primary endpoints were the variation between injection (D0) and day 90 (D90) of the thumb pain measured on 11 point-Likert scale (0 to 10) and the patient's self-assessment of efficacy (0 to 3). Treatment consisted in a single injection of 0.6 to 1 ml of HANOX-M-XL, a viscosupplement made of a cross-linked HA of high molecular weight, from biofermentative origin, combined with mannitol. All injections were performed under fluoroscopic or ultrasound guidance. Predictive factors of pain decrease were studied in univariate and multivariate analysis. All statistical tests were carried out two tailed at the 5% level of significance. Results: 122 patients (76% females, mean age 60, mean disease duration 36 months) were included and 120 (98%) were assessed at 3 months. 23% of the TMC OA were grade 1 according to Dell classification, 36.8% grade 2, 36.8% grade 3% and 3.5% grade 4. At D0, the average (SD) pain level was 6.5±1.6 without significant difference between Dell groups (p=0.21). At day 90, pain decreased from 6.5±1.6 to 3.9±2.5 (Difference −2.7±2.5; −42%; p<0.0001) without significant difference depending on the Dell grade (p=0.055), despite a seemingly smaller number of responders in stage 2 patients. The average analgesic consumption decreased in more than one out of two patients. In univariate analysis, the clinical response was significantly worse in patients taking NSAIDs at baseline (p=0.012), but this difference no longer reached the significance threshold in the multivariate analysis. In multivariate analysis no predictor of response was identified. There was no safety issue. All AEs (11%) were transient increase of pain during or following HA administration and resolved without sequel within 1 to 7 days. Conclusions: This study, of the largest cohort of patients treated with viscosupplementation in TMC OA, suggests that a single course of HANOX-M-XL injection is effective in relieving pain, without safety concern. Interestingly patients with the more advanced stages of OA seemed to benefit the treatment as well as those with less advanced OA. Disclosure of Interest: J. DAUVISSAT: None declared, T. Conrozier Consultant for: Labrha SAS, Speakers bureau: Labrha SAS, H. Lellouche: None declared, B. MAILLET: None declared, C. Rizzo: None declared, V. Travers: None declared, V. locquet: None declared, S. Mellac-Ducamp: None declared