Adult acquired flatfoot deformity or posterior tibial tendon dysfunction is a gradual but progressive loss of ones arch. The posterior tibial muscle is a deep muscle in the back of the calf. It has a long tendon that extends from above the ankle and attaches into several sites around the arch of the foot. The muscle acts like a stirrup on the inside of the foot to help support the arch. The posterior tibial muscle stabilizes the arch and creates a rigid platform for walking and running. If the posterior tibial tendon becomes damaged or tears the arch loses its stability and as a result, collapses causing a flatfoot. Adult flatfoot deformity can occur in people of all ages and gender however, it occurs most commonly in sedentary middle aged to elderly females. There are several risk factors for posterior tibial tendon dysfunction that include: obesity, steroid use, systemic inflammatory diseases such as rheumatoid arthritis, trauma, being born with a low arch, and diabetes. It occurs most commonly in one foot however, it can occur in both feet especially in people with systemic diseases such as diabetes and rheumatoid arthritis.
Posterior tibial tendon dysfunction is the most common cause of acquired adult flatfoot deformity. There is often no specific event that starts the problem, such as a sudden tendon injury. More commonly, the tendon becomes injured from cumulative wear and tear. Posterior tibial tendon dysfunction occurs more commonly in patients who already have a flat foot for other reasons. As the arch flattens, more stress is placed on the posterior tibial tendon and also on the ligaments on the inside of the foot and ankle. The result is a progressive disorder.
Patients will usually describe their initial symptoms as “ankle pain”, as the PT Tendon becomes painful around the inside of the ankle joint. The pain will become more intense as the foot flattens out, due to the continued stretching and tearing of the PT Tendon. As the arches continue to fall, and pronation increases, the heel bone (Calcaneus) tilts into a position where it pinches against the ankle bone (Fibula), causing pain on both the inside and outside of the ankle. As the foot spends increased time in a flattened, or deformed position, Arthritis can begin to affect the joints of the foot, causing additional pain.
Observe forefoot to hindfoot alignment. Do this with the patient sitting and the heel in neutral, and also with the patient standing. I like to put blocks under the forefoot with the heel in neutral to see how much forefoot correction is necessary to help hold the hindfoot position. One last note is to check all joints for stiffness. In cases of prolonged PTTD or coalition, rigid deformity is present and one must carefully check the joints of the midfoot and hindfoot for stiffness and arthritis in the surgical pre-planning.
Non surgical Treatment
Because of the progressive nature of PTTD, early treatment is advised. If treated early enough, your symptoms may resolve without the need for surgery and progression of your condition can be arrested. In contrast, untreated PTTD could leave you with an extremely flat foot, painful arthritis in the foot and ankle, and increasing limitations on walking, running, or other activities. In many cases of PTTD, treatment can begin with non-surgical approaches that may include. Orthotic devices or bracing. To give your arch the support it needs, your foot and ankle surgeon may provide you with an ankle brace or a custom orthotic device that fits into the shoe. Immobilization. Sometimes a short-leg cast or boot is worn to immobilize the foot and allow the tendon to heal, or you may need to completely avoid all weight-bearing for a while. Physical therapy. Ultrasound therapy and exercises may help rehabilitate the tendon and muscle following immobilization. Medications. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, help reduce the pain and inflammation. Shoe modifications. Your foot and ankle surgeon may advise changes to make with your shoes and may provide special inserts designed to improve arch support.
For those patients with PTTD that have severe deformity or have not improved with conservative treatments, surgery may be necessary to return them to daily activity. Surgery for PTTD may include repair of the diseased tendon and possible tendon transfer to a nearby healthy tendon, surgery on the surrounding bones or joints to prevent biomechanical abnormalities that may be a contributing factor or both.