Cartilage repair of the knee with Hyalograft C:® Magnetic Resonance Imaging assessment of the glycosaminoglycan content at midterm

The aim of this study was to assess the stability of the glycosaminoglycan (GAG) content in the long term after matrix-associated autologous chondrocyte transplantation (MACT) with Hyalograft C in the knee over a follow-up period of one year. In this cross-sectional evaluation, 11 patients after MACT of the knee consented to delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) measurements. The mean post-operative interval before the first MR examination was 40.6 +/- 22.0 months, and the second MR examination was carried out after another 12 months. The Lysholm score was assessed for clinical evaluation. Quantitative T1 measurements after intravenous negatively charged MR contrast agent administration were performed. Global post-contrast T1 of the reference cartilage and the repair tissue and a relative post-contrast T1 value were calculated. The Lysholm score improved significantly from 59.8 +/- 12.9 at baseline to 86.1 +/- 15.7 at the second visit (p < 0.01). The mean global T1 of the repair tissue (1st visit 581.3 +/- 126.4 ms; 2nd visit 684.1 +/- 169.9 ms; p = 0.104) and the mean relative T1 value showed stable results over one year (1st visit 0.81 +/- 0.28; 2nd visit 0.76 +/- 0.32; p = 0.4). The study demonstrated stable glycosaminoglycan content of the repair tissue after MACT at midterm.