11/12/2014 9:21 AM
A patient presents to the office with a painful 1st MTPJ. On exam you discover a functional hallux limitus and sub-hallux base callusing. Orthotic considerations:
a. Goal of the orthotic: increase 1st mtpj rom
b. Plantarflexing the 1st metatarsal will raise the 1st MTPJ axis of rotation and therefore decrease or eliminate the functional limitus finding. So, casting this foot in STJ neutral with the 1st metatarsal plantarflexed is essential.
c. Couple this casting technique with a semi-rigid polypropylene shell that is wide with a deep heel cup and flat rearfoot post with minimal arch fill to allow continued 1st metatarsal plantarflexion and stability.
d. Additionally, medial skiving and / or inverting the device will decrease medial column load and further plantarflex the 1st metatarsal to un-jam the 1st MTPJ
e. Finally, if this isn’t enough, or if you are troubleshooting on another providers pair of functional foot orthotics, consider adding a Reverse Morton Extension to unload the 1st metatarsal head, therefore plantarflexing it.