Chronic ankle instability: a cadaveric anatomical and 3D high-resolution MRI study for surgical reconstruction procedures

Abstract

Abstract Objectives To quantitatively investigate the anatomy of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) for surgical reconstruction procedures in chronic ankle instability (CAI). Methods 3D MRI was performed on five fresh-frozen cadaveric ankles using six different spatial resolutions (0.3 × 0.3 × 0.3 mm3, 0.45 × 0.45 × 0.45 mm3, 0.6 × 0.6 × 0.6 mm3, 0.75 × 0.75 × 0.75 mm3, 0.9 × 0.9 × 0.9 mm3, 1.05 × 1.05 × 1.05 mm3). After comparing the MRI results with cadaver dissection, a resolution of 0.45 × 0.45 × 0.45 mm³ was selected for bilateral ankles MRI on 24 volunteers. Classification of the ATFL and four distances of surgically relevant bony landmarkers were analyzed (distance 1 and 3, the fibular origin of the ATFL and CFL to the tip of fibula, respectively; distance 2, the talar insertion of the ATFL to the bare zone of talus; distance 4, the calcaneal insertion of the CFL to the peroneal tubercle). Results In subjective evaluation, the interobserver ICC was 0.95 (95% confidence interval (CI): 0.94–0.97) between two readers. The spatial resolution of 0.3 × 0.3 × 0.3 mm3 and 0.45 × 0.45 × 0.45 mm3 received highest subjective score on average and demonstrated highest consistency with autopsy measurements in objective evaluation. Measurements on the 48 volunteer ankles, distance 1 in type I and II were 12.65 ± 2.08 mm, 13.43 ± 2.06 mm (superior-banded in Type II) and 7.69 ± 2.56 mm (inferior-banded in Type II) (means ± SD), respectively. Distance 2 in type I and II were 10.90 ± 2.24 mm, 11.07 ± 2.66 mm (superior-banded in Type II), and 18.44 ± 3.28 mm (inferior-banded in Type II), respectively. Distance 3 and 4 were 4.71 ± 1.04 mm and 14.35 ± 2.22 mm, respectively. Conclusion We demonstrated the feasibility of quantifying the distances between bony landmarkers for surgical reconstruction surgery in CAI using high-resolution 3D MRI. Critical relevance statement High-resolution 3D MRI examination may have a guiding effect on the preoperative evaluation of chronic ankle instability patients. Key Points Spatial resolutions of 0.3 × 0.3 × 0.3 mm3 and 0.45 × 0.45 × 0.45 mm3 demonstrated highest consistency with autopsy measurements. The spatial resolution of 0.45 × 0.45 × 0.45 mm3 was conformed more to clinical needs. 3D MRI can assist surgeons in developing preoperative plans for chronic ankle instability. Graphical Abstract

Keywords

• Chronic ankle instability
• Anterior talofibular ligament
• Calcaneofibular ligament