Microfracture in the Ankle: Clinical Results and MRI with T2-Mapping at 3.0 T after 1 to 8 Years

Background: Microfracture (MFX) is frequently used to treat deep cartilage defects in the ankle; however, the data on repair tissue (RT) quality after MFX are very limited at this time. T2-mapping at 3 T has been optimized for the ankle and can be used to noninvasively evaluate cartilage collagen and water content. The aim of this study was to determine if the RT after MFX in the ankle had T2 properties similar to the adjacent reference cartilage (RC). Methods: Fourteen cases after MFX in the ankle were assessed with morphological MRI and T2-mapping at 3 T. The American Orthopaedic Foot and Ankle Society (AOFAS) score and a modified Cinicinnati Knee Rating System rating were used to evaluate the clinical outcome. The MRI protocol included a 3-dimensional sequence and a proton-density sequence for morphological evaluation and a multiecho spin echo sequence for T2-mapping. Region of interest analyses were carried out in accordance with the morphological images to ensure complete coverage of the defect site. Results: Both clinical scores demonstrated significant improvement at the time of the MR examination (P < 0.001). RT T2 was 49.3 +/- 10.1 (range, 35.7-69.3) milliseconds, and RC T2 was 49.9 +/- 8.2 (range, 38.4-63.7) milliseconds (P = 0.838). Relative T2 (rT2) was 1.00 +/- 0.20 (range, 0.72-1.36). Conclusion: MFX in the ankle can provide RT with T2 properties similar to adjacent cartilage.