Posterior Tibial Tendon Dysfunction (PTTD)

What is the posterior tibial muscle?

The posterior tibial muscle is the primary dynamic supporter of the foot arch. The muscle is responsible for inverting the rearfoot, adducting/supinating the forefoot, and plantarflexing the ankle. It’s major antagonist is the peroneus previous and activation of the PTT locks the transverse tarsal joint causing the foot to be a rigid lever arm during toe off. 

What is PTTD?

PTTD is when the posterior tibial tendon is injured or slowly degrades overtime causing the development of adult acquired flat feet. Risk factors for developing PTTD is obesity, age, female sex, DM, corticosteroid use, seronegative inflammatory disorders. When someone begins to develop flattening of the arch the posterior tibial tendon begins to fire longer and harder to help recreate an arch, which leads to overuse and degeneration. 

How is PTTD classified?

The most common classification that is used to evaluate and treat PTTD is by Johnson and Strom. Stage 1: no deformity but inflammation of the tendon, no deformity, + single heel raise, and normal X-ray. Stage 2a: flatfoot with flexible rearfoot and normal forefoot, – single heel raise, X-ray show collapse of arch. Stage 2b: flatfoot with flexible rearfoot and forefoot abduction ( + too many toe sign = >40% Talonavicular uncoverage) stage 3: flat foot with rigid forefoot abduction and rigid rearfoot valgus, – single heel and X-ray show subtalar arthritis. Stage 4: rigid forefoot and rearfoot with deltoid compromise. X-ray show subtalar arthritis and valgus talar tilt in ankle. 

How to treat PTTD?

Stage 1: supportive athletic shoes with custom orthotic. stage 2 will depending on what are the major planes of deformity of the flat foot, but the most common procedures are Evans, MDCO, TAL/gastrocnemius recession, 1st TMTJ arthrodesis, FDL tendon transfer, and spring ligament repair. Stage 3 will be have same procedures of stage 2, but with the addition of a subtalar joint arthrodesis. Stage 4 depends on the amount of ankle arthritis if none or mild consider a medial double or triple arthrodesis with deltoid ligament reconstruction, other procedures could be a TTC or a staged procedure with flatfoot reconstruction and then total ankle replacement. Alternatively for stage 2/3/4 if a patient does not want surgery they can use an ankle foot orthosis such as an arizona or richie brace. 

surgical video of calcaneal osteotomy and FDL tendon transfer:

If you have foot or ankle pain and would like a consultation. Make an appointment at Orange County Podiatry with Dr. Andrew Yang or call (949) 651-1202