Efficacy, Tolerability and Adverse Events of Single-Shot Intra-Articular Hyaluronic Acid Injection in Knee Osteoarthritis

Objective: The clinical experience with single intra-articular hyaluronic acid injection in knee OA is limited. The aim was to assess the therapeutic efficacy, tolerability and adverse events of single-shot intra-articular hyaluronic acid injection in knee OA.Method: Between February 2008 and December 2010, forty eight (48) patients (Males=21, Females=27) with OA knees were enrolled in this prospective study. These patients had failed to respond adequately to conservative treatment including analgesics and rehabilitative modalities. The inclusion criteria were (1) Resting visual analog scale pain of >50 mm and (2) Radiographic evidence for osteoarthritis and at least one of the following three characteristics; Age ≥50yrs, Morning stiffness ≤ 30 min in duration and coarse crepitus on motion (as per American College of Rheumatology guidelines 1986). Functional scoring as per WOMAC and VAS for pain at rest and during walking was documented. Patient satisfaction was documented as per Linkert scale. Patients received a single injection of Synvisc-One (consisting of 6 ml hylan G-F 20). The patients were reviewed at 1 month, 3 months and 6 months post- injection with final analysis at 1 year. Use of only paracetamol, when required was allowed for concomitant analgesia.Results: The mean age of the patients was 65 ± 5 years; mean duration of symptoms 5.4 ± 1.5 years and mean body mass index (BMI) 29.1 2 kg/m . Bilateral knees were involved in 69% of patients. Knee swelling and effusion was present in 70% and 31.5 % patients, respectively. All the patients were available at final follow-up. The resting and walking VAS pain significantly improved from baseline after the injection (45 from 70 and 50 from 82, respectively). There was significant improvement of pain and disability based on the WOMAC scores. Adverse events were recorded and included local pain and swelling, mild redness, and/or effusion in the knee. Based on “Knee Society Score” the overall efficacy was judged as excellent in 55%, satisfactory in 43%, and poor in 2 %. The beneficial effects stayed till 6 months but returned to baseline at last follow up at 1 year.Conclusions: This study confirmed the therapeutic efficacy and safety of single-shot intra-articular injection of hyaluronic acid for the treatment of osteoarthritis of the knee. The pain relief and functional improvement lasts for up to 6 months. The procedure is tolerated well and associated with very few local adverse events. The need for concomitant analgesia is reduced. JMS 2015; 18(2):128-133