Repair tissue quality after arthroscopic autologous collagen-induced chondrogenesis (ACIC) assessed via T2*mapping

A novel single-stage approach using arthroscopic microdrilling and atelocollagen/fibrin-gel application is employed for cartilage repair of the knee. The purpose of our study was to investigate the morphological and biochemical MRI outcome after this technique. A retrospective case series of ten patients (mean age 45 years) with symptomatic chondral defects in the knee who were treated arthroscopically with microdrilling and atelocollagen application was analyzed. All defects were ICRS grade III or IV and the sizes were 2-8 cm(2) intra-operatively. All patients underwent morphological MRI and T2-star mapping at 1.5 T at 1-year follow-up. The magnetic resonance observation of cartilage repair tissue (MOCART) score was assessed. T2* relaxation time values of repair tissue and a healthy native cartilage area was assessed by means of region of interest analysis on the T2* maps. The mean MOCART score at 1-year follow-up was 71.7 +/- 21.0 ranging from 25 to 95. The mean T2* relaxation times were 30.6 +/- 11.3 ms and 28.8 +/- 6.8 ms for the repair tissue and surrounding native cartilage, respectively. The T2* ratio between the repair tissue and native cartilage was 105 % +/- 30 %, indicating repair tissue properties similar to native cartilage. An arthroscopic single-stage procedure using microdrilling in combination with atelocollagen gel and fibrin-glue can provide satisfactory MRI results at 1-year follow-up, with good cartilage defect filling. The T2* values in the repair tissue achieved similar values compared to normal hyaline cartilage.