Chronic posterior tibial tendon insufficiency can result in acquired adult flatfoot deformity. This is a chronic foot condition where the soft-tissues (including the posterior tibial tendon, deltoid and spring ligaments) on the inside aspect of the ankle are subject to repetitive load during walking and standing. Over time these structures may become painful and swollen ultimately failing. When these supporting structures fail the result is a change in the alignment of the foot. This condition is typically associated with a progressive flatfoot deformity. This type of deformity leads to increased strain on the supporting structures on the inside of the ankle and loading through the outer aspect of the ankle and hind-foot. Both the inside and outside of the ankle can become painful resulting significant disability. This condition can often be treated without surgery by strengthening the involved muscles and tendons and by bracing the ankle. When non-operative treatment fails, surgery can improve the alignment replace the injured tendon. Alignment and function can be restored, however, the time to maximal improvement is typically six months but, can take up to a year.
The posterior tibial tendon, which connects the bones inside the foot to the calf, is responsible for supporting the foot during movement and holding up the arch. Gradual stretching and tearing of the posterior tibial tendon can cause failure of the ligaments in the arch. Without support, the bones in the feet fall out of normal position, rolling the foot inward. The foot's arch will collapse completely over time, resulting in adult acquired flatfoot. The ligaments and tendons holding up the arch can lose elasticity and strength as a result of aging. Obesity, diabetes, and hypertension can increase the risk of developing this condition. Adult acquired flatfoot is seen more often in women than in men and in those 40 or older.
At first you may notice pain and swelling along the medial (big toe) side of the foot. This is where the posterior tibialis tendon travels from the back of the leg under the medial ankle bone to the foot. As the condition gets worse, tendon failure occurs and the pain gets worse. Some patients experience pain along the lateral (outside) edge of the foot, too. You may find that your feet hurt at the end of the day or after long periods of standing. Some people with this condition have trouble rising up on their toes. They may be unable to participate fully in sports or other recreational activities.
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
It is imperative that you seek treatment should you notice any symptoms of a falling arch or PTTD. Due to the progressive nature of this condition, your foot will have a much higher chance of staying strong and healthy with early treatment. When pain first appears, your doctor will evaluate your foot to confirm a flatfoot diagnosis and begin an appropriate treatment plan. This may involve rest, anti-inflammatory medications, shoe modifications, physical therapy, orthotics and a possible boot or brace. When treatment can be applied at the beginning, symptoms can most often be resolved without the need for surgery.
The indications for surgery are persistent pain and/or significant deformity. Sometimes the foot just feels weak and the assessment of deformity is best done by a foot and ankle specialist. If surgery is appropriate, a combination of soft tissue and bony procedures may be considered to correct alignment and support the medial arch, taking strain off failing ligaments. Depending upon the tissues involved and extent of deformity, the foot and ankle specialist will determine the necessary combination of procedures. Surgical procedures may include a medial slide calcaneal osteotomy to correct position of the heel, a lateral column lengthening to correct position in the midfoot and a medial cuneiform osteotomy or first metatarsal-tarsal fusion to correct elevation of the medial forefoot. The posterior tibial tendon may be reconstructed with a tendon transfer. In severe cases (stage III), the reconstruction may include fusion of the hind foot,, resulting in stiffness of the hind foot but the desired pain relief. In the most severe stage (stage IV), the deltoid ligament on the inside of the ankle fails, resulting in the deformity in the ankle. This deformity over time can result in arthritis in the ankle.