Classification systems are in use everyday in the medical field. Everything from kidney, and heart disease, to the stages of cancer, right down to the pathology or problems found in the feet. The staging systems enable clinicians to organize their thoughts when evaluating conditions, communicate with other physicians, and discuss prognostics (or future course of the disease) based on the level of disease. Having flatfeet and a condition called posterior tibial tendon dysfunction (PTTD) go hand-in-hand. There are four stages to PTTD. One textbook states that the stages of PTTD should be viewed as a “syndrome in which there is a spectrum of clinical presentations.”1 In a recent post, I mentioned the last stage of flatfeet, “flattest of the flat,” in which I described the last and final stage. The PTTD, or flatfoot can be viewed as a progressive dsisorder, in which a patient progresses from one stage the next over time.
The Flatfoot Spectrum (stages 1-4)
The location of the pain, function of the posterior tibialis tendon, and amount of deformity will typically distinguish one category from another. Using the diagram below will help in understanding the different terms that are used to describe this condition.
Pain and swelling are the hallmarks of this stage. The pain is generally located along the course of the posterior tibial tendon, as seen in the image to the left, and at the end of the tibia bone, called the medial malleolus. Function of the posterior tibial tendon is preserved at this stage, and major deformity, i.e. hind foot valgus, and too-many toes sign, are absent. Part of the examination at this in every stage is to ask the patient to perform a single toe raise, meaning that with one foot off the ground, the patient goes up on there could be toes on the other leg. This maneuver usually only causes pain with repetition.
At this stage, the tendon starts to stretch out and degenerate. There is obvious deformity present as well. As noted in the image above, there is hind foot valgus, and the forefoot may have started to abduct or turn outward. Further deformity at this stage includes collapse of the medial or inner arch of the foot, or collapse of the talonavicular joint. Although there is deformity present, the deformity remains “flexible.”
By the time a patient reaches stage 3, the deformity becomes rigid. The deformity of the forefoot is demonstrated in the image to the right and is called “forefoot varus.” When the patient is standing flat, the arch is collapse. In this stage, the deformity at the hindfoot (heel) and forefoot can no longer be reduced. There is tightening of the posterior muscle group, (the calf muscles). Usually, by this stage there is no longer pain on the inside of the foot or ankle, and it is all moved to the outside of the foot. Most patients will describe this as outside of the ankle pain, at the fibula or just below it. Pain at rest is common as the arthritic process sets in.
The forces involved in this deformity will overtime create an arthritic condition. In the case of flatfoot, the wear and tear on the foot and its structures progresses towards arthritis and changes in which the tendons and ligaments don’t support the bones and the bones rub away the cartilage at the joints leading to arthritis. Stage four or endstage flatfoot is an arthritic foot condition. The pain described in stage 3 is more due to ankle arthritis than it is to the structures encroaching on one another.
3. Mann’s Surgery of the Foot and Ankle, Chapter 25, figure 25-4
1. Mann’s Surgery of the Foot and Ankle