Efficacy and safety study on a new compound associating low and high molecular weight hyaluronic acid in the treatment of hip osteoarthritis

The combined use of low and high molecular weight hyaluronic acid (HA) has never been reported in the treatment of osteoarthritis (OA). The aim of this paper was to evaluate the efficacy of a new hybrid association of both preparations in patients suffering from hip OA and to compare the results with those obtained retrospectively from a cohort of patients treated with high molecular weight HA. Twenty patients with moderate-severe hip OA (grade II–IV according to Kellgren-Lawrence score) were enrolled in the study group. After clinical and functional evaluation (Visual Analogue Scale [VAS] for pain, Lequesne Index, Harris Hip Score), each participant received an intra-articular ultrasound-guided injection of the new HA compound at baseline and after 40 days. The measures were repeated at three and six months. The data collected were retrospectively compared with those obtained in a cohort of 20 patients, matched for sex, age, and severity of hip OA, treated with high molecular weight hyaluronic acid. The intra-group comparison showed a significant improvement in clinical and functional outcomes at three and six months in both cohorts, while the infra-group comparison showed better results in the patients treated with the study compound at six months (VAS at rest, P <0.04; VAS during activities, P <0.02; Harris Hip Score, P <0.001). The present study is the first which demonstrates that a combination of low and high molecular weight HA is effective and safe in the management of patients suffering from hip OA and provides better therapeutic results in comparison to high molecular weight HA. We may infer that both HA preparations work synergically, enhancing their positive activities.