The forefoot is subjected to a varying physiological load. The metatarsi should thus possess normal mobility, active and passive stability, and shape (hg. 1 and 2). If any or several of these conditions are not met, they give rise to articular, ligamentous, and skeletal metatarsal abnormalities respectively. Reference is made to these minor pathologies which, with regard to the morphology of the forepart of the foot, give rise to a change in metatarsal function only. Ligamentous diseases secondary to degeneration or inflammation (round, triangular forefoot, etc.) are not included. The clinical picture of intermediate metatarsal instability comprises: a) static intermediate metatarsal pain; b) clinical evidence of intermediate metatarsal instability; c) callosity in a few cases; d) slight divergence of the metatarsi under load; e) young subjects f) absence of stable secondary forefoot deformity; g) absence of metatarsal bone or joint disease; h) frequent bilaterality. Diagnosis is solely dependent on the history and clinical picture. Radiography merely serves to determine whether any other disease is present. Intermetatarsal neosyndcsmoplasty is based on these biomechanical, anatomopathological and clinical premisses. It is designed to provide functional, not morphological correction of the forefoot, i.e. re-establishment of the tension equilibrium between the metatarsi by means of distal intermetatarsal neoligaments on their necks. The new ligament is the EPA (occasionally the palmaris longus) half-tendon from the ipsilateral tarsus. Its length is calculated with precision intraoperatively. A curved transverse incision at the heads is followed by careful longitudinal dissection of the underlyng planes to achieve good distal skeletrization of the metatarsi. Next, tunneling of the necks is carried out. This must never be transverse to prevent weakening or fracture of the dorsal cortex. The half-tendon (still attached to the distal section of the EPA) is passed through the tunnels and placed dorsally with respect to the interosseous muscles to prevent impairment of their function. The half-tendon is detached, and the medial head is turned like a tie on the superolateral angle of the neck of the 1st metatarsus and sutured to the first new ligament. A similar procedure is followed for the lateral head. This is turned back medially on the neck of the 5th metatarsus, and attached by single, non-absorbable stitches to the 4th new ligament. Anchorage of the medial and lateral heads of the complete neoligament must not alter the shape of the forefoot, even if it is deformed, since the sole purpose of the operation, as already stated, is re-establishment of the tension equilibrium between the intermediate metatarsi. Simple layer by layer suturing completes the operation. An elastic bandage with flat medication is worn for 20 days. Gradual loading is allowed after two months and free loading after three.