The role of the plantar first metatarsal first cuneiform ligament in weightbearing on the first metatarsal.

Twelve below the knee amputation specimens were examined while a dorsally directed force was applied to the first metatarsal. Seven specimens were tested with serial removal of soft tissues, followed by cutting the plantar first metatarsocuneiform ligament. Five specimens had only the plantar first metatarsocuneiform ligament cut, leaving the other structures intact. In both groups, dorsal displacement of the distal first metatarsal was noted to be more than 5 mm after sectioning of the ligament, with no marked change noted during removal of other soft tissues. This study demonstrates that the plantar first metatarsocuneiform ligament is the major component in the stabilization of the first metatarsal during weightbearing.