Adult-acquired Flatfoot due to posterior tibial tendon dysfunction (PTTD)
Adult-acquired flatfoot is most frequently caused by posterior tibial tendon dysfunction, which results in flattening of the arch of the foot, valgus deformity of the calcaneus (heel) and abduction of the forefoot, which most of the time goes unnoticed. (underdiagnosed). It is a painful deformity due to the progressive deterioration of the ligamentous structures that make up the support of the medial longitudinal (internal plantar) arch of the foot, and a series of pathological changes occurring to the tendon and other structures of the ankle, midfoot and hindfoot since they constitute an essential stabilizer for these structures.
What causes are associated with tendon dysfunction?
Mechanical: Tendinous insufficiency and repetitive overload during walking.
Vascular theory: Absence of mesotendon and retromalleolar hypovascularization zone.
Others: Collagen diseases with an incidence of 20%.
What are the most common risk factors for this condition?
It is more frequent in the female sex, and when a previous circulatory disorder, overweight and diabetes mellitus can be found often. It appears in the 4th - 5th decade of life (its maximum incidence peak is around 55 years). It’s very common in runners due to repetitive overloading of the tendon.
What symptoms and signs can we detect?
We can find a progressive (gradual) deformity of the inner region of the foot with descent of the medial longitudinal arch, which makes the foot flat, irreducible hindfoot valgus may also appear, due to the stiffness of the joint and the functional disability of the tendon. As a consequence, we will observe deformations in footwear as a noteworthy new feature. It is unilateral in the vast majority of cases. Initially it causes pain that increases as the deformity progresses, and is accompanied by edema and hypersensitivity (increased sensitivity) behind the medial malleolus (inner ankle) which corresponds to the location of the posterior tibial tendon sheath. It can appear acutely (suddenly) when the tendon suddenly breaks. In the early stages, the deformation is reducible but over time it becomes fixed, complicating the clinical picture with a more complex and invasive treatment.
There are signs that are very easy to observe and which can guide us towards the diagnosis.
“Too many toes” sign. It quantifies the abduction of the forefoot and its presence is constant in the most advanced degrees of the condition, although not pathognomonic.
It is evaluated by observing the standing patient from behind, with both feet equidistant from the midline and in equal rotation. (View image)
The “too many toes sign” is positive if from a posterior view we see more than 3 toes, as can be seen in the image. It happens due to loss of function of the posterior tibial tendon and overexertion of the flexor hallucis and flexor digitorum communis.
Rodríguez Fonseca's sign: In stages III and IV where the flatfoot deformity has become fixed. When the patient stands on tiptoes, the heel is placed in varus (to the outside) but if there is an injury to the tibialis posterior the heel remains in valgus (to the inside). Keep in mind that this movement requires good mobility of the subtalar joint. (View image)
What other problems can it cause?
- Patellar tendinopathy.
- Sprains of the medial collateral and anterior cruciate ligaments of the knee.
- Hip problems such as trochanteritis due to muscle strain caused by posterior tibial insufficiency.
What elements should we take into account to diagnose it?
Physical examination is essential for all the clinical elements that may be present.
It is very important to compare with the contralateral side. Direct pressure along the course of the tibialis posterior tendon causes pain. If there is a rupture, it can be palpated. To locate the exact point of injury, the patient must be examined against muscular resistance, to encourage the tendon to become prominent and facilitate palpation.
It is also important for the diagnosis to determine muscle function. The single-foot elevation test and the Rodríguez Fonseca test will determine the strength of the tibialis posterior.
The GOLD STANDARD complementary test to diagnose this pathology is ultrasound, which is a quick, painless test for the patient and rules out other pathologies.
However, X-rays in different views are also very useful.
Grade I: Radiologically there are few signs of loss of normal joint alignment.
However, in the other grades, characteristic radiological changes are observed. (View image)
We can also indicate an MRI and a CT scan.
Is there any treatment that can help improve the symptoms and stop the progression of the deformity?
Yes. There are many things we can do and different combinations of treatments:
Conservative, rehabilitative and surgical. Always taking into account the degree of dysfunction and the biomechanical alterations of the gait, as well as the individual characteristics of each patient (time of evolution, level of physical activity, weight, chronic diseases present, etc.)
Used if diagnosed in the early stages, to stabilize the joint and control inflammation and pain.
- Pharmacological: Analgesics and non-steroidal anti-inflammatory drugs.
- Rehabilitation Treatment: (To stop or contain the descent of the arch of the foot, correct the valgus of the hindfoot and stabilize the gait). Among which we can mention:
Functional bandages to reduce the tension of the tibialis posterior tendon, correct the position of the foot and relieve pain.
Podiatric insoles (after studying the footprint) to correct the position of the foot and optimize muscle function, allowing it to be efficient. In addition to correcting all the peculiarities that are causing an incorrect gait.
Strength-building and stretching exercises.
Buerger Allen exercises to improve venous return circulation.
Massage therapy: Relaxing, Cyriax deep transverse and evacuative massage.
- Shock waves.
- Magnet therapy.
- Low and medium frequency analgesic currents.
- Traditional Natural Medicine.
- Ozone therapy.
Surgical treatment is indicated when conservative treatment fails. To determine the necessary surgical procedure, it is important to determine if the deformity is flexible or rigid.
- Arthrodesis with medializing calcaneal osteotomy. Via the medializing osteotomy of the calcaneus, it is possible to move the mechanical axis of the foot medially, aligning it with the axis of the tibia and medializing it in respect to the axis of the subtalar joint, thus restoring the function of the triceps surae as heel inverter and correcting the valgus deformity in the hindfoot.
- Tenodesis for reconstruction of the ligament and the common flexor of the fingers.
The most common cause of this adult-onset deformity is posterior tibial tendon dysfunction (PTTD). It is a disabling disease.
In the first two stages, a combination of orthoses and/or functional bandages, strengthening and stretching exercises, therapeutic ultrasound, and the use of analgesics and non-steroidal anti-inflammatory drugs, have a satisfactory result with a remission of symptoms in more than 80% of patients. Hence the importance of early diagnosis to correct the deformity, relieve symptoms and avoid surgical treatment as well as improve quality of life.