The posterior tibial tendon is one of the strongest supporters of the arch. The muscle originates in the back of your leg and its tendon courses around the inside of your ankle and inserts primarily into the navicular bone. The greatest stress is placed on the tendon when stepping onto the foot, as it works to prevent the collapse of the arch. When it is overused or stressed, it can develop tendonitis.
Pain may be experienced anywhere along the tendon, from the bottom of the arch to the inside of the ankle. Over time, the tendon become dysfunctional in its ability to support the arch. A flat foot type can exacerbate this condition, adding more stress to an already diseased tendon, creating a vicious cycle.
Clinical examination often shows pain on direct pressure on the tendon, weakness of the muscle, a progressing flatfoot deformity, and inability to raise the heel while standing on the affected foot. Diagnostic imaging with x-rays, ultrasound and MRI will
further evaluate the extent tendon injury and the resultant bone and joint changes.
Acute phase treatment includes rest, ice, immobilization and anti-inflammatory medication. Chronic inflammation is treated with physical therapy, orthotics, bracing, and high-topped shoes. Surgical intervention may be required to repair the degenerated tendon and/or address the underlying faulty mechanics associated with the flat foot.