OBJECTIVE: To evaluate the normal location of the peroneus longus tendon (PL) in the
cuboid groove in various ankle-foot positions by ultrasonography in asymptomatic volunteers.
METHODS: Ultrasonographic assessment of the PL in the
cuboid groove was performed in 20 feet of ten healthy volunteers. Each PL was examined in five ankle-foot positions (i.e., neutral, dorsiflexion, plantar-flexion, supination, and pronation). The PL location was qualitatively categorized as \"inside\" when the PL was entirely within the cuboid groove, as \"overlying\" when some part of the PL was perched on the cuboid tuberosity, and as \"outside\" when the PL was entirely on the
cuboid tuberosity. For quantitative evaluation of the PL location, the distance between the PL and the cuboid groove was measured. The width of the
cuboid groove was measured in the neutral position.
RESULTS: The PL location did not significantly change with changes in the ankle-foot position. Qualitatively, an \"overlying\" PL was the most common type, regardless of the ankle-foot position. \"Inside\" PLs were found in only 35, 20, 30, 25, and 35% of feet in neutral, dorsiflexion, plantar-flexion, supination, and pronation positions, respectively. The quantitative PL location was also not significantly different among all ankle-foot positions and it was significantly negatively correlated with the cuboid groove width.
CONCLUSIONS: In healthy volunteers, 65% or more of the PLs were partially or completely located outside of the cuboid groove, regardless of the ankle-foot position. The PL location relative to the
cuboid groove was related to the
cuboid groove width.