A Randomized, Controlled Trial Comparing Autologous Matrix-Induced Chondrogenesis (AMIC®) to Microfracture: Analysis of 1- and 2-Year Follow-Up Data of 2 Centers

Abstract

Microfracture (MFx) is currently the recommended option for the treatment of small cartilage defects but is not regarded as suitable for the treatment of defects larger than 2.5 cm(2). To extent its applicability to medium-sized defects MFx has been combined with a collagen type I/III matrix (Chondro-Gide(®)). This technique is called Autologous Matrix-Induced Chondrogenesis (AMIC(®)) and meanwhile a clinically established treatment option for localized full-thickness small- to medium-sized cartilage defects. Despite its more spreading clinical use, clinical data published so far are limited to mainly case report series. In this study, we report the first results of a randomized, controlled trial assessing the efficacy and safety of AMIC(®) versus MFx. Patients enrolled in 2 centers were included in this analysis. 38 patients (aged 21-50 years, mean defect size 3.4 cm(2)) were randomized and treated either with MFx, with sutured AMIC(®) or glued AMIC(®). Clinical outcomes (modified Cincinnati and ICRS score) could be assessed in 30 patients at 1-year and 27 patients at 2-years post-operation. Improvements in both scores were seen at 1-and 2-years post-operation, irrespective of the technique used. MRI assessment revealed a satisfactory and homogenous defect filling in the majority of patients. No treatment-related adverse events were reported. This interim analysis confirms the mid-term results for AMIC(®) reported in literature. It demonstrates clearly that clinical outcomes at 1-year post-operation are maintained at 2-years. Therefore we consider enhancing MFx with Chondro-Gide (®) is a valid and safe cartilage repair option for small- to medium-sized cartilage defects of the knee.

Keywords: Articular cartilage; Autologous matrix-induced chondrogenesis (AMIC®); Chondro-Gide®; knee surgery.; microfracture.

Fig. (1)

Enrollment and outcome measures for the 3 treatment options: microfracture, sutured AMIC® and glued AMIC®.

Fig. (2)

Box and Whisker plot of the Modified Cincinnati Scores at baseline (BL) and at 1-(1y) and 2-years (2y) post-operation for the three treatment groups: MFx (a), sutured AMIC® (b) and glued AMIC® (c). Scores are presented as medians; the ends of the boxes define the 25th and 75th centiles and the minimum and maximum score is indicated.

Fig. (3)

Modified ICRS Score - patient assessments. Functional status was rated by the patient at baseline (BL) and at 1- (1y) and 2-years (2y) post-operation for the three treatment groups. Stacked bar charts show the number of patients with the corresponding functional status for each treatment group at BL and at 1 and 2 years.

Fig. (4)

Box and Whisker plot of the Modified ICRS Score - patient assessments. Pain was rated by the patient at baseline (BL) and at 1- (1y) and 2-years (2y) post-operation for the 3 treatment groups. Scores are presented as medians; the ends of the boxes define the 25th and 75th centiles and the minimum and maximum score is indicated.

Fig. (5)

Modified ICRS Score - surgeon assessments. Classification of the affected knee (a), crepitation (b), and functional status (c) were assessed by the baseline (BL) and at 1- (1y) and 2-years (2y) post-operation for the three treatment groups. Stacked bar charts show the number of patients with the corresponding functional status for each treatment group at BL and at 1 and 2 years.

Fig. (6)

MRI follow up at 1 year post-operation (glued AMIC®, medial femoral condyle): Proton density weighted sequence (PDw) in sagittal orientation. Defect filling almost complete (20 x 20 mm, see arrow), surface remaining slightly uneven, good marginal integration, cartilage repair tissue isointense to adjacent genuine cartilage.