First tarsometatarsal joint: anatomical biomechanical study.

We studied the function of the first tarsometatarsal joint in 100 specimens of 53 cadavers. The study showed that an adduction and abduction movement described earlier was present only in approximately 10% of the specimens. Moreover, eversion of an average of 6.2 degrees often only occurs as a result of dorsal displacement of the joint surfaces of the first metatarsal in relation to the first cuneiform by an average of 2.6 mm. All other movements in the frontal, horizontal, and sagittal plane can be disregarded or are the result of this movement. New conclusions may be drawn from these results, especially with regard to subcapital osteotomies of the first metatarsal and the adductor transfer according to McBride in metatarsus primus varus. These findings challenge the value of the McBride transfer.