Morphological evaluation of the calcaneofibular ligament in different ankle positions using a three-dimensional MRI...

Evaluating images of the lateral ligament of the ankle is not easy, and evaluation of the calcaneofibular ligament (CFL) in particular is difficult. We prospectively conducted morphological measurements of the CFL in different ankle positions and obtain basic data for use in functional assessment of the CFL, diagnosis of CFL injury, and determination of treatment effects.

The subjects were ten healthy volunteers (ten ankles) with a mean age of 27.8 years and no history of ankle disease. Imaging was done using a 3-T magnetic resonance imaging (MRI) machine and fast imaging employing steady-state acquisition cycled phases (FIESTA-C), a three-dimensional (3D) sequence, with the ankle in a neutral position, maximum dorsiflexion, and maximum plantar flexion. 3D images of the CFL, peroneal muscle tendons, fibula, and calcaneus were prepared at a workstation, and morphological measurements of the CFL were made.

In all positions, the CFL showed a gently curving course with the peroneal muscle tendons as a fulcrum. The tortuosity angle was significantly smaller in plantar flexion (30.0° ± 7.4°) than in the neutral position (41.7° ± 8.3°).

3D MRI sequences showed that, in all positions, the CFL curved due to the influence of the peroneal muscle tendons. With maximum plantar flexion, the CFL tortuosity angle was small, which was thought to have been due to the tension in the CFL.