As the foot goes through the gait cycle of supination to pronation to supination, the posterior tibial tendon is pulling upwards to supinate the foot and relaxes, yet remains tight to prevent over pronation. The tendon originates in the back of the leg and extends down behind and under the inner ankle joint. It connects underneath the navicular bone which is just in front of the heel bone on the inside of the foot.
Symptom of Posterior Tibial rupture or tendinitis
As you get up and bare weight and the foot goes into an over pronated position stress is applied on to the insertion point of the tendon at the underside of the navicular bone. Swelling, along with pain can occur at this point. Also when going through the final stage of gait called toe off, the bending of the toes causes the tendon to pull up creating supination and causing pain at the insertion. A simple test to see if this is the posterior tibial tendon that is causing the pain is to do a single limb heel raise. The foot which has the pain remains flat on the floor while lifting the other foot off the floor. At this point you go up on your toes of the foot remaining on the floor. Should pain occur at the insertion point then it is defiantly a tear or rupture to the posterior tibial tendon. You should go to your doctor for further diagnoses.
Cause of Posterior Tibial rupture or tendinitis
The cause of Posterior Tibial tendon tear or rupture is most often due to a trauma, forcing the foot to over pronate severely and quickly. The tendon is not allowed enough time to relax placing the stress on the insertion point. If the tendon is overly tight due to the tightness in the calves, then the tendon will not have the elasticity to absorb this stress. If the tendon is just a tear the pain will be more intense. If the tendon is ruptured the pain will be quite a bit less but you will not be able to walk without your arch collapsing severely. This could then create other pain on the top of the foot. Other underlying conditions that can place stress on the Posterior Tibial tendon would be a Hallux rigidus and leg length differences. The more factors the more susceptible one is to the injury.
Treatment of Posterior Tibial rupture or tendinitis
In the event that this is a rupture or broken bone, the tendon will have to be surgically reattached or the bone repaired. If this is only a tear, it is customary to place that foot into a walking cast to allow time for the tendon to heal. You need to have the doctor, physical therapist, or come in to our facility to check for a leg length difference due to the walking cast being higher. This is to prevent any discomfort to the hips. After the tendon has healed and before the foot is taken out of the walking cast, range of motion at the ankle must be tested and if the foot is not allowed to properly bend upwards 15 degrees then the tightness in the calf will cause the foot to over pronate and reinjure the posterior tibial tendon. A stretching program will be needed to loosen up the calf muscle before much weight bearing is done without the cast. The Stretching program can be found at the menu for feet hurt. If necessary a heel lift can be put in both shoes to help take the stress off the tendon. In addition it would be wise to put some sort of an arch support in your shoes to prevent over pronation. Discussing the type of arch support best suited for your situation should be done with a Pedorthist, who has experience with this problem. Shoes, though they won’t treat the cause, they can reduce the stress on the tendon. Getting into a shoe with a very stiff sole and a high toe spring, can take a lot of the stress off the tendon.