Why The Coleman Block Test Is Beneficial In Orthotic Prescription Writing For Lateral Instability

I did a consult with a colleague regarding how to write the best orthotic prescription for a patient who was laterally unstable. The colleague stated that in the biomechanical exam he measured the resting calcaneal stance position as nearly 10 degrees inverted.

I then asked if he had performed the Coleman block test to determine whether it was the forefoot that was holding the foot inverted or if this patient had a rigid inverted rearfoot. He had not checked that and did not know the answer. This is a critical question when looking at a patient who has an inverted heel so he decided to have the patient return to the clinic so he could perform the Coleman block test.

The Coleman block test consists of supporting the lateral forefoot in order to determine if an inverted heel is due to a forefoot issue, such as a plantarflexed first ray. A rigid plantarflexed first ray can result in inversion of the heel in order to bring the lateral forefoot to the ground. If the rearfoot is not otherwise rigidly inverted and the lateral forefoot is supported, then the heel will evert to perpendicular.

In my office, I often use a catalogue or a pile of physical therapy prescription forms under the fourth and fifth metatarsal heads to support the lateral forefoot.

The colleague did bring the patient back in and found that when he supported the lateral forefoot, the heel came to a perpendicular position. In this situation, one should prescribe an orthotic device that aims to support the lateral forefoot. We do not really need to worry about rearfoot control.

By definition, a properly balanced functional orthotic will balance the forefoot to rearfoot relationship. Accordingly, the orthotic plate itself will help support the lateral forefoot. In addition, I suggested adding a valgus forefoot extension to this orthosis. Ideally, the extension would be located on the device and extend out under the metatarsal heads. A valgus extension is thicker laterally and thinner medially. I usually start with the extension about 3 mm thick laterally but one can modify this while doing the Coleman block test. 

I also recommend gluing the cover of the orthosis posterior only so it is easy to adjust the valgus extension by either increasing or decreasing its thickness. If the Coleman block test is negative, meaning there is no change in the inverted heel position when the lateral foot is supported, then it would be contraindicated to add a valgus extension. In that case, the valgus extension would simply increase pressure under the metatarsal heads without changing the rearfoot position.

Editor’s note: This blog was first published at https://prolaborthotics.com/Blog/tabid/90/EntryID/359/Default.aspx and has been adapted with permission from Lawrence Huppin, DPM, and ProLab Orthotics. For more information, visit www.prolaborthotics.com .