Viscosupplementation for hip osteoarthritis: Does systematic review of patient-reported outcome measures support use?

Introduction: Osteoarthritis of the hip is one of the leading causes of disability worldwide. There is lack of agreement among providers and governing agencies regarding the efficacy of hyaluronic acid (HA) for the management of hip osteoarthritis (OA). Therefore, the purpose of this systematic review was to determine how HA administration impacts 1) patient reported outcome measures (PROMs) and 2) rates of conversion to THA. Methods: The PubMed, EBSCO host, and Google Scholar electronic databases were queried for all studies published between January 1st, 2000 and January 1st, 2020 that reported on outcomes following HA administration for treatment of hip OA. The following keywords were implemented with AND and OR Boolean operators: "hip"; "osteoarthritis"; "arthritis"; "viscosupplementation"; "hyaluronic acid." Our final analysis included 39 studies and reported on a total of 5,864 patients receiving injections of HA. Results: All studies reporting on visual analog scale (VAS), patient global assessment, and total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores demonstrated improvements following HA administration. For the Lequesne Index (LI), WOMAC pain, WOMAC function, and Harris Hip Score (HHS) values, a majority of studies reported that HA would prove beneficial, with one analysis suggesting a lack of improvement. There was inconsistent evidence across studies regarding the effectiveness of HA compared to other infra-articular injections. The formulation of the administered viscosupplementation did not appear to influence outcomes. Furthermore, rates of conversion to THA were relatively low when evaluating 1- to 4-year follow-up intervals. Discussion: Non-comparative studies consistently demonstrated that HA can achieve satisfactory pain reduction and functional improvement. However, there was not enough evidence in the current literature regarding whether HA is superior to placebo or other types of infra-articular injections. Future studies should continue to compare HA to other treatment modalities in randomized controlled trials with larger sample sizes.