The first metatarsal cutout or first ray cutout is a common modification used in orthotics to allow the first ray to plantarflex in order to treat functional hallux limitus. I think it should be noted, however, that if a practitioner takes extremely good negative cast and writes an appropriate prescription and uses an orthotic lab and does not overfill the medial arch the first ray cutout should rarely be necessary.
The orthosis goal in the presence of functional hallux limits is to allow the first ray to plantarflex. This can be accomplished by plantarflexing the first while taking the negative casts, prescribing a minimum cast fill with approximately 2 to 3 degrees of inversion and ensuring that your orthotic lab does not overfill the medial arch. In the presence of these items the first ray should be allowed to plantarflex quite effectively in order to decompress first MPJ motion and enhance a windlass function. An orthosis made in this manner will conform very close to the arch of the foot when the foot is held in neutral position with the first ray plantarflexed. It should conform closest posteriorly and flare away from the foot anteriorly.
Because all of the doctors in my clinic follow these guidelines when treating fHL, we never prescribe first ray cutout. I do, however, use first ray cutouts in my office on occasion. The most common time I do so is when the patient comes in with an orthosis received from another practitioner where the orthotic device does not conform very close to the arch of the foot. Because in the situation the foot has to flatten and the first ray has to elevate in order to reach the orthosis I want to somehow enhance plantarflexion of the first ray. The first ray cutout or first metatarsal cutout, along with a reverse Morton’s extension, is good option in this situation.
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