A common cause of weakness and an inability to stand on one’s toes is due to Posterior Tibial Tendon Dysfunction (PTTD). The posterior tibial tendon is one of the most important tendons in the lower leg. This tendon starts in the calf, extends behind the inside of the ankle, and attaches to multiple bones in the middle of the foot. This muscle and tendon combo help lift the inside part of the foot as well as plantarflex the foot. Plantarflexion is a movement that increases the angle between the foot and the shin like pushing down on a car’s gas pedal.
The posterior tibial tendon is constantly used. It helps hold up the arch of the foot and during walking it provides support when stepping off the toes. If this tendon becomes inflamed, over stretched, or torn many things can happen. First pain and swelling is typically noticed on the inside of the ankle. Soreness over the arch can occur, especially with activity. This soreness can increase leading to a loss of the foot’s arch. General weakness and an inability to stand on the toes can also occur. Posterior tibial tendon dysfunction occurs most often in women over 50 years of age but can also be brought on by obesity, diabetes, previous surgery or trauma, local steroid injections, or an inflammatory disease.
A podiatrist will reach the conclusion of PTTD through a history and physical examination. During the physical exam it is common to have the patient stand on their bare feet facing away from the physician. This allows the physician to notice how the foot functions. From behind, it will look as though you have too many toes showing. A podiatrist may also ask the patient to stand on their toes or do a single heel raise. During a single heel raise, the heel will normally rotate inward. The absence of this sign indicates PTTD. The treatment a podiatrist recommends will depend on how far the condition has progressed. The ultimate goal is to return the tendon to normal functioning and to prevent permanent flatfoot. In the early stages, PTTD is treated with ibuprofen, shoe inserts, or immobilization of the foot. If early treatments do not work surgery may be needed.