OBJECTIVES: Retrospective study  to determine whether THR may be delayed by the use of US-guided Intra-articular injection (USGIAI) of hyaluronic acid (HA), in hip joint in patients affected by  hip OA. METHODS: We evaluate the delaying in the THR considering 176 patients suffering from hip OA and treated with HA USGIAI, candidates for THR according to the judgment of six orthopaedics. Then, we imaging two hypothetic populations of 1000 patients each candidates to THR, the first undergoing to 1 injection of HA (HyalOne-Hyalubrix 60) USGIAI and the second one undergoing to THR for a follow-up period of one year and four years. We performed the cost evaluation on hip surgery, eventual revision of the prosthesis, post-operative complications and mortality, rehabilitation, lost working days. RESULTS: At 24 months, 159 out of 76 (90 %) patients did not undergo to THR. At 48 months, 82 % (N = 144) of the study population treated with HA USGIAI avoided THR. In the group of 93 patients candidates for THR (that is, in which 4, 5, or 6 orthopaedic surgeons agreed that the patient was a suitable candidate for THR), only 17 had undergone THR, with survival results of 82 % at 24 months. At 48 months, this percentage reduced to 66 % in this group. Results show that the treatment with HA USGIAI is the most favorable option, from a clinical and economic perspective, and also considering the social impact (higher value of quality-adjusted life-years (QALYs)). Analyzing hospital perspective, there are even higher benefits, estimated to be between approximately 940,000 euros in one year and 580,000 euros after 4 years. CONCLUSIONS: Data simulation comparing HA USGIAI vs THR in patients eligible for surgery, shows that HA viscosupplementation has the most favorable outcome, both from a clinical and economic point of view.