Tarsal Coalition

Tarsal Coalition
Approach to Tarsal Coalition

Incidence about 1%, Male > Female, probably hereditary component to it
Associated Conditions:
Apert Syndrome – synostosis of the tarsal and cranial bones, mid-face hypoplasia, syndactyly
Nievergelt-Pearlman Syndrome – multiple congenital anomalies including tarsal and radioulnar synostosis
PFFD, fibular hemimelia, ball and socket ankle (may represent adaptive changes of the ankle secondary to subtalar motion restriction because of the tarsal coalition)

Can be fibrous, cartilaginous, or osseous
Talonavicular ossify between 3-5 years; calcaneonavicular between 8-12 years; talocalcaneal between 12-16 years
(These times correlate with when they become symptomatic)
The talocalcaneal coalitions most commonly involve the middle facet which is supported by the sustentaculum tali on the medial aspect of the talus.

On history, get the history of pain; may find that they have recurrent ankle sprains, stiff flatfoot.
On physical, note the stiffness of the hindfoot

Get x-rays: Oblique X-ray show the calcaneonavicular coalition. Harris views visualize the talocalcaneal coalitions
Then get a CT scan.

Treatment: basically 3 choices – symptomatic/conservative, excision, fusion
Resection of calcaneonavicular coalitions give the best results. Talocalcaneal ones don’t fare as well. If there are degenerative changes present or if excision fails, then do a triple arthrodesis.

Approach

Do the hx and px.
Get the x-rays and CT to confirm diagnosis. Beaking does not equal arthritis.
Send off for conservative management – activity modification, shoe modification, insole, short leg cast

Calcaneonavicular Coalition Excision – results are generally good; lean towards excision vs fusion.
– oblique incision dorsolaterally, centered over the coalition (palpable as a fullness in the area of the sinus tarsi.
– identify and sharply elevate EDB from its origin
– protect peroneal tendons and sural nerve in the lower part of the incision
– identify the coalition, and also identify where the TN, TC, and CC joints are to prevent injury to them
– use two sharp metacarpal osteotomes to cut out a rectangle of bone so that there is no bony bridge at the bottom.
– bone wax to the surfaces; get a free fat graft from the buttock and put it in as a spacer.
– repair EDB origin

Talocalcaneal Coalition Excision – if arthritis is present, or it involves ant/post facets – triple arthrodesis
(be aware that excision tends to do not as well as in calcaneonavicular)
– medial approach to the middle facet, approximately 6 cm in length, centered over the sustentaculum tali
– reflect abductor hallucis
– dissect out the tendons and neurovascular structures behind medial malleolus; FDL, FHL, and NV bundle are usually draped under sustentaculum and need to be dissected free and protected.
– often easier to find the posterior facet and trace it distally to find the posterior edge of the coalition
– the anterior aspect of the coalition can be found by finding FHL running directly beneath it.
– after defining the extent of the coalition, remove it with osteotomes, rongeurs, or power burr
– must completely resect until there demonstrated motion at the subtalar joint.
– bone wax surfaces, then put retrocalcaneal adipose tissue as interposition (or take fat graft from buttock)

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