Ultrasound-Guided Hip Injections with High Density Hyaluronic Acid: Outcome at One Year Follow Up.

: The ultrasound-guided viscosupplementation of the hip joint with hyaluronic acid (HA) is considered a standard procedure among the conservative treatments for hip arthritis. The aim of this study was to evaluate the clinical benefit and the incidence of adverse events of the technique in an observational study at one year follow up. We evaluated a consecutive series of 85 patients with a diagnosis of symptomatic arthritis who underwent intra-articular ultrasound-guided hyaluronic acid injections. The scales used for evaluation were modified Harris Hip Score (mHHS), WOMAC (Western Ontario and McMaster University), and Hip Outcome Score (HOS) with subscale Sport (HOSs), for pain the Visual Analogic Scale (VAS). The patients were classified according to Tonnis' radiological classification of arthritis (range 0-3): 20 patients (grade 0), 32 (grade 1), 18 (grade 2), 15 (grade 3). At last follow up, all the scales increased: mHHS from 59.35 to 82.1, HOS from 69.45 to 78.53, HOss from 47.4 to 58.11, VAS from 6.09 to 3.97, WOMAC from 33.2 to 31.5 ( < 0.05 for all the parameters); the results were elaborated with GraphPad Prism v5.0 (Prism Software La Jolla, CA, USA) using Wilcoxon's test. A total of 13 patients out of 85 needed arthroplasty, all classified as Tonnis grade 3. No serious adverse events were noted due to the procedure. Based on our findings, indication for the use of hyaluronic acid is limited to patients with mild to moderate arthritis. Patients in advanced arthritis refusing replacement surgery and asking for this treatment should be informed about the poor results of the technique even in the short term.