Effectiveness of intra-articular injections of hyaluronic acid for the treatment of knee osteoarthritis: results of a series of patients treated in a Pain Unit

Abstract

Objective: To evaluate the results of treatment of knee osteoarthritis with a single intraarticular injection of hyaluronic acid in terms of pain reduction, joint function improvement and duration of effects. Method: Patients with clinical and radiological diagnosis of osteoarthritis at different stages of evolution in one or both knees were treated at the Pain Unit of a tertiary hospital. Sociodemographic and clinical characteristics provided by the patient following the usual clinical practice were prospectively collected. Pain at rest, walking, up and down stairs, morning stiffness, time walking as well as time/quality sleep were recorded pre and post-treatment. At post-treatment visit the degree and duration of improvement experienced, as well as the investigator assessment were also recorded. The treatment consisted of a single intraarticular injection of hyaluronic acid, with the possibility of a booster. Results: A total of 29 patients (52 knees) were included. Both knees were treated in 23 of them (n=46) and only one knee in the remaining 6. The 92.3% were osteoarthritic joints with an evolution> 12 months, with clinical grade 4-5 in 61.6% (n = 32) and radiological grade III-IV of Kellgren & Lawrence in 67.7% (n=35), making 55.8% of cases were classified as severe by the investigators. There was a significant improvement in all parameters of pain and function considered (p <0.001). Walking time increased by over 100% and 67.3% of patients defined their quality of sleep as normal, compared to 38.5% at baseline. The improvement was assessed by the investigator as good or very good in 73.1% of cases. Conclusions: Our study confirms the effectiveness of a single injection of hyaluronic acid to reduce symptoms in patients with knee osteoarthritis with different grades of severity, with results that remain between 6 and 12 months and are especially significant in those patients with mild to moderate osteoarthritis.