We had a question from a client this week as to whether we would recommend a first ray cutout for a pes cavus foot with plantarflexion of the first ray.
Since the entire idea behind this orthosis is to encourage the first ray to plantarflex, or to put it another way, to prevent the first ray from dorsiflexing, as I mentioned in the previous article, if you plantarflexed the first ray, prescribed a minimum fill, and are using an orthotic lab that does not overfill the medial arch of the positive cast then the orthosis should conform well to the arch of the foot and let the first ray plantarflex. If any of these things do not happen then the orthosis is likely to gap from the arch, which means it will apply more force to the first ray distally and actually act to dorsiflex the first ray. If this is the situation then a first ray cutout can be beneficial and allow the first ray to plantarflex.
Because I plantarflex the first ray when I cast, commonly prescribe a minimum fill and use an extremely high quality orthotic lab that pays close attention to their cast work. I rarely have to use a first ray cutout on my own orthotic devices. I do some times have a patient with cavus foot and plantarflexed first ray who presents and already has a pair of orthosis. If those orthoses do not adequately conform to the foot and allow the first ray to plantarflex then I will often add a first ray cutout to those devices.