Review Question - QID 241

A Lisfranc amputation is through the tarsometatarsal joints, except the 2nd metatarsal, which is osteotomized to preserve the stability of the medial cuneiform. To prevent the patient from supinating the foot following this amputation, the evertors on the foot must be maintained. The principal evertors are the peroneus brevis and longus (Illustration A). Therefore, the function of the peroneus brevis must be preserved. Technically this is done preserving the soft-tissue envelope (peroneus brevis, tertius and plantar fascia) around the fifth metatarsal base.

Illustration B depicts the level of a Lisfranc amputation of the foot.

Incorrect Answers:
1-The posterior tibialis is the primary supinator of the foot, and releasing it would lead to an eversion deformity. The tibialis posterior tendon attachment to the bases of the second and third metatarsals will actually be released with this amputation, but the main attachment to the navicular preserved.
3-The anterior tibialis dorsiflexes and inverts the foot, but transferring it to the medial and middle cuneiforms would mimick its native function to dorsiflex and invert the foot.
4-A lengthened Achilles would lead to increased dorsiflexion, not supination.
5-Osteotomy of 2nd MT is crucial to preserve the medial cuneiform and midfoot stable.