Are prefabricated foot orthoses still effective in reducing plantar pressures after 12 months of wear?

Cronkwright, D.G, Spink, M.J, Landorf, K.B, & Menz, H.B.Gait Posture. (2011) Oct;34(4):553-7. doi: 10.1016/j.gaitpost.2011.07.016. Epub 2011 Aug 19.

Formthotics continue to reduce plantar pressure after or more 12 months of wear

In this study of older adults who had been wearing Formthotics dual density red for at least 12 months, in shoe pressure data was collected both with the old Formthotics and new Formthotics of the same density. The results showed no significant difference between the two groups, indicating that there is only a small deformation over a twelve month period. Therefore in this age group there may not need to replace Formthotics as often as previously thought.

(2011) Research paper