Effect of intra-articular injection of intermediate-weight hyaluronic acid on hip and knee cartilage: in-vivo evaluation using T2 mapping

We used T2 mapping to quantify the effect of intra-articular hyaluronic acid administration (IAHAA) on cartilage with correlation to clinical symptoms. One hundred two patients with clinical and MRI diagnosis of hip or knee grade I-III chondropathy were prospectively included. All patients received a standard MRI examination of the affected hip/knee (one joint/patient) and T2-mapping multiecho sequence for cartilage evaluation. T2 values of all slices were averaged and used for analysis. One month after MR evaluation 72 patients (38 males; mean age 51 +/- 10 years) underwent IAHAA. As a control group, 30 subjects (15 males; 51 +/- 9 years) were not treated. MR and WOMAC evaluation was performed at baseline and after 3, 9, and 15 months in all patients. T2 mapping in hyaluronic acid (HA) patients showed a significant increase in T2 relaxation times from baseline to the first time point after therapy in knees (40.7 +/- 9.8 ms vs. 45.8 +/- 8.6 ms) and hips (40.9 +/- 9.7 ms; 45.9 +/- 9.5 ms) (p < 0.001). At the 9- and 15-month evaluations, T2 relaxation dropped to values similar to the baseline ones (p < 0.001 vs. 3 month). The correlation between T2 increase and pain reduction after IAHAA was statistically significant (r = 0.54, p < 0.01) in patients with grade III chondropathy. T2 mapping can be used to evaluate the effect over time of IAHAA in patients with hip and knee chondropathy. aEuro cent T2 relaxation times change over time after hyaluronic acid intra-articular administration aEuro cent T2 relaxation times of the medial femoral condyle correlate with WOMAC variation aEuro cent T2 relaxation times are different between Outerbridge I and II-III.