Musculo-skeletal   [back to the Category]

The posterior tibio-talian syndrome or posterior impingement syndrome   [read the french version]

Author :   Docteur Anne Thiescé

The posterior tibio-talian syndrome or posterior impingement syndrome

All injuries to the posterior part of the ankle, with the exception of those to the
Achilles' tendon, are included in this syndrome. Repeated use of plantar flexion makes this syndrome particular to ballet. Fig 1.

Continual hyperextension of the ankle or maximum plantar flexion compresses tissues which may or may not cause osseous contact. This contact depends on the morphology of the posterior tubercle of the talus: large or short tubercle or presence of an os trigonum. Thus, the various anatomical structures representing the posterior impingement syndrome are prone to considerable constraints that result in acute or chronic injuries which are often wrongly interpreted as pain from the Achilles' tendon.


Clinical Picture

Pain begins on the postero-external side of the ankle and reappears during "pointe" and "demi-pointe" exercises and in "dégagé". Pain appears progressively on the posterior part of the ankle during prolonged overexertion, particularly after several months of forced exercises badly suited to the "instep". Pain is initially felt during forced plantar flexion and will progressively restrict this flexion. The early clinical indication to look for is pain during forced passive plantar flexion, coupled with calcaneal valgus and varus movements, thus indicating pincers’ syndrome.

Physiopathology

Acute osseous injuries:

- Fracture of the talar postero-external tuberculum (TPET) or fracture of the os trigonum resulting from a forced plantar flexion movement when jumping, or during dorsiflexion with the foot in slight eversion and external rotation during a jump landing, or during a fall on to the heel with the foot in slight plantar flexion. The posterior edge of the tibia strikes the TPET or fractures the os trigonum by trapping it against the calcaneum.

- Fracture of the posterior articular margin of the tibia, or osseous squame is caused by a detachment of the insertion of the inferior and posterior fibulo-tibial ligament, resembling the immediate consequences of a lateral sprain. The symptomatology, in all these acute osseous injuries, is identical to that of lateral sprains.

Chronic osseous injuries

- Either the large posterior tubercle of the talus syndrome with extensive TPET and occasional sub-chondral bone condensation, hollowed by multiple small calcaneum geodes; Fig 2.

- Or the os trigonum syndrome. This is a bone that is to be found in between 8 and 13% of the population and which is usually asymptomatic; it can result from pseudarthrosis following a TPET stress fracture; when there is no fracture, a chronic irritation can exist, caused by repeated constriction of the bone and its capsulo-ligamentary structures; Fig 3.

- Or direct tibio-calcaneal conflict in the case of a talus with a short posterior tubercle; this is rare. It was discovered during a surgical operation, performed as a result of ineffective medical treatment, visualising a chondropathy of the posterior part of the calcaneal thalamus.

Chronic injuries of the soft parts

The posterior tubercle of the talus is short. There is pinching of a posterior synovial fold situated between the MFHL sulcus and the fibular sheath between the posterior margin of the tibia and the calcaneus. Plantar flexion is once again at fault, but this time, in association with twisting foot movements as for "pirouettes".
The clinical picture is slightly different. Pain occurs during exercise, in plantar and dorsal flexion and quickly becomes a constant companion. The indication for pincers’ syndrome is erratic and is accompanied by local bloating; there is no sign of tendinitis.

These various injuries can be secondary to a displaced accessory soleus muscle, an exostosis or a synovial cyst.
If there is anterior laxity in the ankle, the talian tenon can slide forwards into the tibio-fibular mortise during weight-bearing exercises. Furthermore, the appearance of the posterior impingement syndrome is favoured by a neglected sprained ankle or chronic laxity in the antero-posterior ankle. The associated tenosynovitis, especially tenosynovitis of the flexor hallucis longus muscle, can sometimes mask this syndrome.

Additional examinations

- X-rays: a strict profile of the ankle, with a profile in maximum plantar flexion, can show the irregular aspect of a fracture line and differentiate the X-rays of a TPET from an os trigonum; Fig 4.

- The positive osseous scintigraphy confirms the recent nature of the fracture; Fig 5.

- The scanner shows whether or not there is osseous corticale on the osseous fragment in case of osseous conflict; thus, it differentiates between fractures of the TPET and os trigonum and allows the state of the injury to be ascertained;

- The arthroscanner looks for MFHL tenosynovitis where soft tissue conflicts are concerned. It shows the presence of a pathological tissue structure and prominently displays hypertrophy and the posterior synovial recessus oedema.

Treatment

Medical treatment must be followed even though it is long and difficult. The treatment rests on partial or complete rest with no weight-bearing or a rigid resin support, for 2 to 3 weeks, the use of NSAID and re-education involving physiotherapy and antero-posterior ankle stabilization. The choice of ballet shoes and even the shape of the soles can be varied in order to make the "arch" protrude mid-foot and restrict plantar flexion of the tibio-talian articulation. The situation can be improved by administering one or two corticoid infiltrations either via postero-externally or via intra-articular anterior.
Treatment of acute osseous injuries lies in the wearing of a resin boot for 6 weeks. The main complications of these fractures are pseudarthrosis and the persistence of a chronic painful syndrome in the postero-external section of the ankle.

Surgical treatment is suggested if medical treatment fails or when faced with the association of this syndrome with MFHL tenosynovitis especially if osseous conflict is present. The ablation of the tubercle or of the os trigonum would then be carried out. This surgery can be followed by early re-education. The gain in plantar flexion amplitude is immediate and is a big advantage. Ballet can be resumed between the 3rd and the 8th month. Where other conflicts are concerned, surgical treatment can sometimes be suggested, however, there is no guarantee that ballet can be resumed. The best results are to be found amongst ballet dancers who do not use "pointe" ballet shoes, the traditional choice for men and other types of dancing.


The frequency of the posterior impingement syndrome and the difficulty of its treatment make prevention preferable.

Passive stretching of the arch obtained by "forcing", although sometimes necessary, must, above all, stretch the mid-tarsus whilst restricting the stretching of the tibio-talian articulation. The convexity of the foot that gives it its outline and its stability on "pointe" and "demi-pointe", is obtained by "sticking out the arch" in a deliberate, controlled action. Active exercises are not necessarily governed by laxity, even extreme, obtained passively. A sublime foot in "dégagé" can be "en marteau" for "enchaînement", or only balance on the returned instep. Active exercises, which with deliberate control remain the least aggressive, must take priority as much in line with the aesthetics linked to ballet as in that of minor anatomical constraints.


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