Difference in pain and accuracy of two hyaluronic acid injection techniques for symptomatic knee osteoarthritis in overweight patients

Objectives: To evaluate differences of injection related pain, and the accuracy of the techniques in two groups of overweight patients, performing the anterolateral approach for one group (G1) and the superolateral approach for the second group (G2). Material and methods: In the study, 126 knee joints from 86 osteoarthritis (OA) patients were evaluated. Inclusion criteria were body mass index (BMI) >= 25, absence of effusion and coagulopathy. Pain evaluation during injection was evaluated with Visual Analogue Scale (VAS), while accuracy of the procedure was evaluated with ultrasound (US). Results: The patients' mean age was 69.9 +/- 9.01, VAS for G1 group was 1.71 +/- 1.89, for G2 group was 1.74 +/- 1.31. Mean BMI was 29.69 +/- 2.86, for G1 group was 28.29 +/- 3.29, for G2 group was 30.32 +/- 2.41. No adverse events (AE) occurred in both studied groups. The accuracy rate of the procedure was 69.1% for G1 (38/55 knees), 95.7% for G2 (68/71 knees). No significant difference was found in VAS pain score between G1 and G2 group (p = 0.45). We found the significant correlation between BMI and VAS pain score in anterolateral accesses (G1) (r = 0.51; p < 0.005). No correlation was found between age and VAS pain score in anterolateral access (G1). For the superolateral access (G2), no correlation was found for age or BMI and VAS pain score. Conclusions: Hyaluronic acid injection is safe therapeutic option for knee OA with no significant differences between anterolateral and superolateral approaches in terms of pain in overweight patients. However, higher BMI seems to be a predictor of pain in anterolateral access, and the superolateral approach should be preferred in this group of patients.