"Suspected Mechanisms in the Cause of Overuse Running Injuries: A Clinical Review"; Ferber, Hreljac-Sports Health May 09".
This is not the first article asking the question, "What constitutes a normal foot?", & states, "minimal and conflicting experimental evidence supports excessive foot pronation as a contributing factor in the cause of injuries."
The bottom line is be cautious when recommending orthotics for your athletes with MTSS or PFSS. As far as I'm concerned, the majority of the time a customized felt insert works just fine. Things like training progression, work-rest intervals, variety, overall body strength/fitness, pelvic hip mostibility are more important.