The Medicine

Plantar fasciitis is a quite common*, very painful foot problem caused by repeated tension on the plantar aponeurosis (or plantar fascia), a ligamentous structure that runs from the calcaneus (heel) to the bases of the proximal phalanges (toes), which results in inflammation. It is found most common in individuals who participate in high stress activities such as long-distance running, and until just recently there were only ways to deal with, never eliminate, the pain. A presentation today at the annual meeting of the Radiological Society of North America has given hope to those who suffer from this debilitating condition, and it is all done in one nice little outpatient procedure.

In this study, Dr. Luca M. Sconfienza of the University of Genoa and colleagues use an ultrasound-guided technique coupled with a steroid injection to lay the issue to rest once and for all. The procedure begins with a local anaesthetic, followed by repeated puncturing of the effected fascia with the very same needle (A technique known as ‘Dry-needling‘) to induce bleeding; this bleeding, in turn, facilitates quick healing. To eliminate the already inflamed fascia from becoming even more inflamed as a result of the dry-needling, Sconfienza injects a steroid. In all, the procedure lasts a total of 15 minutes and boasts a 95% success rate.

The Natural History

So, why us? Don’t other primates have this issue? I mean, we all have feet… right?

Well, yes, we do, but it turns out that, even so, plantar fasciitis is unique to humans. This is because the condition affects the pedal arch, a portion of our anatomy that is required for bipedal locomotion, a portion of our anatomy which is unique to humans within the order Primates. You see, during ambulation there are points in time at which we are effectively balancing on one foot (Up to, and during, the swing phase of the contralateral leg), and in this one foot the pedal arch serves to absorb some of the energy, the ground reaction force, and simultaneously accumulates passive elastic energy that is used for toe off.

From the paleontological evidence we find that the pedal arch is one of the earliest adaptations of humans to bipedal locomotion. As far back as 3.5mya at Laetoli in Tanzania are footprints which demonstrate the necessity of the pedal arch:

Without this pedal arch we have some serious issues on our hands. As can been illustrated by certain individuals who lack the arch, and the protection provided by it, may suffer from fatigue fractures of the metatarsals, fibula and tibia. Conditions such as hallax varus and hallax vagus, where the metatarsal of the big toe (hallux) is forced out of alignment, are also associated with complications of the pedal arch.

So, as you might guess, without the adaptation that is the pedal arch we would have likely been unable to develop our modern, efficient form of bipedal locomotion, and perhaps would have been left with something like this:

… Which, admitedly, looks much cooler.

*11-15% of all reported foot issues requiring professional help

(References)

Buchbinder, R, 2004, 'Plantar Fasciitis', New England Journal of Medicine, vol. 350, no. 21, pp. 2159-2166. 10.1056/NEJMcp032745

Feibel, C, Agnew, N, Latimer, B, Demas, M, Marshall, F, Waane, S & Schmid, P, 1995, 'The Laetoli hominid footprints—a preliminary report on the conservation and scientific restudy', Evolutionary Anthropology: Issues, News, and Reviews, vol. 4, no. 5, pp. 149-154. 10.1002/evan.1360040502

Latimer, B, 2005, 'Editorial: The Perils of Being Bipedal', Annals of Biomedical Engineering, vol. 33, no. 1, pp. 3-6. 10.1007/s10439-005-8957-8