…are u finding you aren't going thru a full gait???? or simply lacking toe off power???? Morton's toe is a pretty common occurrence, so I'll assume you've worked in the various 'biomechanical' health areas (egs chiro, physio, sports med, podiatrist, pedorthist, etc…..) who actually have some semblance of your areas of concern….as opposed to 'joe blow' physio who deal with avergae 'joe blow' injuries …egs not running oriented….
I am lucky as i have a handful of those people who work at the Olympic level i can turn to when i need to go beyond the tradititonal approach of 'here put some ice on that injury and we'll ultrasdound u later' approach……they are unfortunately extremely difficult to find
…u may want to post on letsrun.com and ask Brian Fullem (a runner who is also a podiatrist) about his opinion as opposed to those of us with only a basic background….he also has a webpage and typically is very open to offering some ideas for u to consider….