Posterior Tibial Tendon Dysfunction (PTTD)

It is a progressive condition in which the tibialis posterior tendon — the main dynamic stabilizer of the foot's medial arch — degenerates and elongates, causing gradual collapse of the foot arch (acquired adult flatfoot). It is the most common cause of acquired flatfoot in adults and predominantly affects women over 40.

The most characteristic signs are: pain on the medial side of the ankle (behind the medial malleolus) that worsens with long walks, progressive flattening of the foot arch compared to the contralateral side, and inability to rise on the toes on single-leg support. If you notice that one foot is becoming "flatter" than the other or there is persistent pain on the inner side of the ankle, seek medical evaluation.

In early stages (I and II), conservative treatment — a medial-arch-support orthosis combined with progressive tendon strengthening — can stabilize or significantly improve the condition in a substantial proportion of patients in clinical series. In advanced stages (III and IV), with rigid deformity and arthrosis, surgery is generally necessary. Early diagnosis is fundamental, since the condition is progressive.

It is the most sensitive clinical test for posterior tibial tendon dysfunction. The patient stands on one leg and tries to rise on the toes repeatedly. Normally, the heel inverts (goes into varus) during the rise. In PTTD, the patient cannot complete the rise, or the heel remains in valgus — indicating failure of the posterior tibial to supinate the hindfoot. It is a simple, quick, and very informative test.

In most stage II cases, long-term continuous use of an orthopedic insole during weight-bearing activities is recommended, since the elongated tendon rarely regains its original length. In stage I, with adequate treatment and effective strengthening, it may be possible to gradually reduce dependence on the orthosis. The decision should be individualized by the supervising physician.

Acupuncture can serve as an adjuvant to conservative treatment, mainly for controlling medial ankle pain that often hampers the start of strengthening exercises. Electroacupuncture at peritendinous points (KI-3, KI-6, SP-5) can support local microcirculation and modulate pain, helping rehabilitation progress. Acupuncture does not replace the orthosis and exercises, which are the pillars of treatment.

Surgery is considered when adequate conservative treatment (orthosis + rehabilitation for 3-6 months) does not produce satisfactory improvement, or in advanced stages (III and IV) with rigid deformity and arthrosis. Procedures vary by stage: tendon transfer with calcaneal osteotomy (refractory stage II), subtalar arthrodesis (stage III), or tibiotalocalcaneal arthrodesis (stage IV). Surgical type is determined by degree of deformity and rigidity.