Adult Acquired Flatfoot Disorder
Is it possible to acquire a flat foot even in adulthood? The answer is yes. A flat foot condition (aka pes planus) is where your foot arch collapses. This is commonly related to posterior tibialis tendon dysfunction (PTTD) (William, et. al., 2000).
Posterior Tibialis Muscle
The posterior tibialis muscle originates mainly from the posterior aspect of the tibia bone, inserting as a tendon underneath the tarsal bones on the inner side of our foot. It inverts (turns the foot inwards), plantarflexes (raises the heel) the ankle joint and acts as the main stabilizer of the foot arch. This allows the calf muscle to work efficiently in walking.
Posterior tibialis during gait
Posterior tibialis is a mian stabilizer of the foot arch which allows optimal and efficient activation of gastronemius during gait.
A dysfunctional posterior tibialis muscle OVERWORKS during walking!
(Semple R Et Al, 2009)
Risk Factors
• Trauma (ankle sprains, fractures, rupture)
• Microtrauma d/t overuse
• Poor blood supply
• Flat feet / Pes planus
• Ligamentous laxity
• Elderly: middle-aged women
• Obesity
• Peroneal brevis overactivity
Posterior to medial malleolus – poorest blood supply to tendon & common area for tendon rupture. (Deland, JT. et. al., 2005)
PTTD is progressive in nature
• Melissa Rabbito., et al: investigated how arch structure may play a role in the progressive nature of PTTD. Runners with PTTD (Stage I) were compared with healthy runners. Runners with PTTD had an increased rearfoot pronation compared to the healthy runners, this pronation places greater strain on the tibialis posterior muscle which explains the progressive nature of PTTD.
4 stages of PTTD
As per Johnson and Strom:
• Stage I: Posterior tibial tendon intact and inflamed (tenosynovitis), no deformity, mild swelling, single-leg toe raise test (+)
• Stage II: Posterior tibial tendon dysfunctional, acquired pes planus but passively correctable (flexible hindfoot), single-leg toe raise test (-), forefoot abduction
• Stage III: Degenerative changes in the subtalar joint and the deformity is fixed (rigid forefoot & hindfoot), severe sinus tarsi pain
• Stage IV ( Myerson): Valgus tilt of talus leading to lateral tibiotalar degeneration, lateral ankle pain
Exercises to fix this issue
- Kulig et al found that, while the use of foot orthoses and stretching was associated with significant improvement in pain and disability in patients with early PTTD, combining custom foot orthoses with eccentric and concentric progressive and resistive exercises accentuated those improvements.
- High repetitions of 200-300reps