Hindfoot alignment of hallux valgus evaluated by a weightbearing subtalar x-ray view

A new radiographic view was proposed to evaluate alignment of the hindfoot under weightbearing condition. The ankle joint and the middle and posterior facets of the subtalar joint were clearly visualized in all radiographs. A comparative study was made of 104 feet with hallux valgus in 58 female patients and 67 normal feet in 57 normal female subjects (control group). The mean value of the angle between the axis of the tibia and a line on the surface of the ankle joint on the talus was significantly larger in the group with hallux valgus than in the control group. Likewise, the mean value of the angle between the axis of the tibia and a line on the surface of the posterior facet of the subtalar joint on the calcaneus in the group with hallux valgus was 95.3 degrees, significantly larger than the 87.9 degrees in the control group. These findings showed that the ankle joint and the posterior facet of the subtalar joint in hallux valgus have valgus deviation. The hindfoot in a foot with hallux valgus has a tendency toward pronation. No previous study has measured the inclination of the posterior facet of the subtalar joint directly in weightbearing.