Hi Mark ... Think about it intuitively ...
Orthotic prescribing is nothing more than matching the requirments needed by the foot to design variables/parameters in an orthotic, which then has to be compromised by environmental factors .... does it really matter if those design variables (and the compromise) are available in a prefab design? Sometimes prefabs have the design parameters needed; sometimes the design parameters can only be achieved in a custom made .... it does not matter if its rheumatoid arthritis or a functional problem.
I am so over the custom made/prefab debate ---- we should be focusing on what are the design parameters needed to achieve the desired outcome.
In your rheumatoid arthritis case, it may have just been about cushioning or off loading or a change in function or spurious (due to the cyclical nature of RA)
PS ... don't forget I am marking the assignment, so I know where you got the info from 