[Rupture of the degenerated posterior tibial tendon--symptoms and therapy].

The tibialis posterior muscle is a powerful flexor and supinator of the hind foot. Considering the plantar extension of its distal tendon, it represents a true antagonist of the short peroneal muscle. It works as a dash-pot for foot pronation under load. Actually, dorsal extension of the foot happens in the tibiotarsal joint but this movement can be increased partially by the subtalar and midtarsal joint, together with pronation. The latter is damped by the posterior tibialis muscle. Its tendon may rupture suddenly, through e.g. a sports accident; it can also rupture insidiously, through a long degenerative process. The rupture causes a chronic overload of the ligaments about the mid foot and a progressive deviation of the talus in flexion and adduction ensures. This may induce osteoarthrosis, especially of the subtalar joint. Treatment depends upon the stage of the lesion. Reconstruction may be performed by augmentation with the flexor digitorum longus tendon. Palliative treatment by triple arthrodesis may be performed in more advanced cases.