The posterior tibialis muscle originates on the bones of the leg (tibia and fibula). This muscle then passes behind the medial (inside) aspect of the ankle and attaches to the medial midfoot as the
posterior tibial tendon
. The posterior tibial tendon serves to invert (roll inward) the foot and
maintain the arch of the foot. This tendon plays a central role in maintaining the normal alignment of the foot and also in enabling normal gait (walking). In addition to tendons running across the
ankle and foot joints, a number of ligaments span and stabilize these joints. The ligaments at the medial ankle can become stretched and contribute to the progressive flattening of the arch. Several
muscles and tendons around the ankle and foot act to counter-balance the action of the posterior tibial tendon. Under normal circumstances, the result is a balanced ankle and foot with normal motion.
When the posterior tibial tendon fails, the other muscles and tendons become relatively over-powering. These muscles then contribute to the progressive deformity seen with this disorder.
Causes of an adult acquired flatfoot may include Neuropathic foot (Charcot foot) secondary to Diabetes mellitus, Leprosy, Profound peripheral neuritis of any cause. Degenerative changes in the ankle,
talonavicular or tarsometatarsal joints, or both, secondary to Inflammatory arthropathy, Osteoarthropathy, Fractures, Acquired flatfoot resulting from loss of the supporting structures of the medial
longitudinal arch. Dysfunction of the tibialis posterior tendon Tear of the spring (calcaneoanvicular) ligament (rare). Tibialis anterior rupture (rare). Painful flatfoot can have other causes, such
as tarsal coalition, but as such a patient will not present with a change in the shape of the foot these are not included here.
Pain along the inside of the foot and ankle, where the tendon lies. This may or may not be associated with swelling in the area. Pain that is worse with activity. High-intensity or high-impact
activities, such as running, can be very difficult. Some patients can have trouble walking or standing for a long time. Pain on the outside of the ankle. When the foot collapses, the heel bone may
shift to a new position outwards. This can put pressure on the outside ankle bone. The same type of pain is found in arthritis in the back of the foot. Asymmetrical collapsing of the medial arch on
the affected side.
The diagnosis of posterior tibial tendon dysfunction and AAFD is usually made from a combination of symptoms, physical exam and x-ray imaging. The location of pain, shape of the foot, flexibility of
the hindfoot joints and gait all may help your physician make the diagnosis and also assess how advanced the problem is.
Non surgical Treatment
The adult acquired flatfoot is best treated early. Accurate assessment by your doctor will determine which treatment is suitable for you. Reduce your level of activity and follow the RICE regime. R -
rest as often as you are able. Refrain from activity that will worsen your condition, such as sports and walking. I - ice, apply to the affected area, ensure you protect the area from frostbite by
applying a towel over the foot before using the ice pack. C - compression, a Tubigrip or elasticated support bandage may be
applied to relieve symptoms and ease pain and discomfort. E - elevate the affected foot to reduce painful swelling. You will be prescribed pain relief in the form of non-steroidal antiinflammatory
medications (if you do not suffer with allergies or are asthmatic). Immobilisation of your affected foot - this will involve you having a below the knee cast for four to eight weeks. In certain
circumstances it is possible for you to have a removable boot instead of a cast. A member of the foot and ankle team will advise as to whether this option is suitable for you. Footwear is important -
it is advisable to wear flat sturdy lace-up shoes, for example, trainers or boots. This will not only support your foot, but will also accommodate orthoses (shoe inserts).
If initial conservative therapy of posterior tibial tendon insufficiency fails, surgical treatment is considered. Operative treatment of stage 1 disease involves release of the tendon sheath,
tenosynovectomy, debridement of the tendon with excision of flap tears, and repair of longitudinal tears. A short-leg walking cast is worn for 3 weeks postoperatively. Teasdall and Johnson reported
complete relief of pain in 74% of 14 patients undergoing this treatment regimen for stage 1 disease. Surgical debridement of tenosynovitis in early stages is believed to possibly prevent progression
of disease to later stages of dysfunction.