The tendon may be described as a « structure exposed to proximal pathogenic events and a typical distal deformity ». On this basis a short report on pathogenic and clinical aspects is presented and the deformity is defined morphologically (true talus foot and dorsiflexion talus foot), pathogenetically (congenital or acquired talus foot) and from a functional point of view (standing and walking). With regard to the functional recovery of Achilles tendon failure reference is made to the various procedures suggested with the conclusion that active functional recovery (tendon transplants) must be combined with correction of the deformity and possibly stabilisation in functional position (arthrodesis). The guiding concepts behind this surgery are outlined and preference is expressed for transplant on the calcaneus of the posterior tibial and short peroneal tendons, muscles automatically synergic with the triceps. This offers the best guarantee of calcaneal stability in walking and the least risk of secondary deformities in relation to their functional suppression by offering simultaneous astragalo-scaphoid and scapho-cuneiform stability. However the fact remains that while improving the morphology of the foot and preventing the development of calcaneal talus, no tendon transplant ever has sufficient strength to allow the subject to walk on tiptoe or walk backwards normally. Functional stability of the calcaneus is already a substantial achievement. In childhood this surgery is a major way of preventing progressive deformity though the patient will never be able to stand on tiptoe and should be performed at an early stage in the presence of rapidly progressing deformity. In many cases bone stabilisation will however have to await skeletal maturity.