The first ray, and specifically related deformities, seem to garner a great deal of attention in the podiatric medicine/surgery field. Most laypersons assume that if you have a "bunion" then the only appropriate treatment is surgery. In some cases surgery is the answer, but pathology of the first ray is progressive, and mechanically based, so it would be logical to think that early intervention to adjust the poor mechanics, may help slow down this progressive problem. A number of research groups have addressed the mechanics of the 1st ray, and a paper by Roukis (1996) focused on the relationship of the position of the 1st ray and the motion of the 1st MPJ. The results of this study are important for our medical community because they establish that as the 1st ray is more dorsiflexed, the motion of the 1st MPJ is decreased. This would lead us to hypothesize that any force, whether internal or external, that leads to an increased dorsiflexed position of the 1st ray, will likely lead to dysfunction (functional hallux limitus) of the 1st MPJ.
Accepting the results of this study, orthotic fabrication should ENCOURAGE PLANTARFLEXION of the 1st Ray and DISCOURAGE DORSIFLEXION of the 1st Ray. To accomplish this goal, the following will be vital: capture the foot image with a non-dorsiflexed 1st ray position (cast or scan); create a arch height shape that encourages plantarflexion of the 1st Ray (minimal cast fill, semi-rigid device); and avoid forces that may lead to dorsiflexion of the 1st ray by using the following suggestions: deep heel cup, wide plate, reverse Morton's extension, medial skive).
Although this may sounds like an "aggressive" device, it is better thought of as an "appropriate" device. By starting with a device that offers ideal characteristics, the practioner can adjust each element for patient comfort and functional control of the 1st ray/1st MPJ relationship.
For more detail on this important article by Roukis et al., read today's EJournal article:
Roukis TS, Scherer PR, Anderson CF. Position of the First Ray and Motion of the First Metatarsophalangeal JAPMA (11):538-46, 1996