Posterior Tibial Tendon Dysfunction (PTTD) is a common cause ankle pain in adults. The loss of normal function in this leg muscle can lead to the development of a flat foot and potentially lead to chronic debilitating ankle pain.
The posterior tibial muscle originates in the back of the leg at the calf and forms the tendon at the inside portion of the ankle prior to its attachment on the foot. The muscle helps to lift the arch during the mid phase of walking as it prepares to lift the heel off of the ground. Excessive strain of this muscle in preparing for heel lift increases the risk of developing inflammation of the tendon termed posterior tibial tendonitis. Untreated posterior tibial tendonitis can progress to tendon tearing or attenuation as seen in PTTD. Gender, age and weight all contribute to the development of this condition but the single most important factor is having a preexisting flatfoot. A flatfoot or excessively pronated foot causes the posterior tibial tendon to work harder to lift the arch in preparation for heel lift. The excessive work load on the muscle causes inflammation and ultimately failure as seen in PTTD.
The pain with PTTD is most notable with initial weight bearing and may be associated with inside ankle swelling. Loss of arch height on affected side as well as the “too many toe” sign is noted with standing. When asked to stand and perform toe raises by getting up on “tip toes” pain is worse at the ankle. Lifting the unaffected foot off of the ground and performing a single toe raise is generally impossible due to the lack of muscle strength and associated pain.
MRI’s can be used to confirm this clinical diagnosis. Early treatment may include use of a removable cast or CAM boot followed by a brace and possibly shoe and orthotic therapies. An orthotic and shoe help support the arch of the foot which decreases the demand on the injured tendon. The severity of the flatfoot will determine whether a shoe and orthotic will alone support the foot enough to improve foot function or if an ankle brace may be required.
Surgical care options exists if conservative care measures fail to relieve pain so early recognition of this condition can be critical in its outcome.