Yes, that is the question. Howell says that lateral heel release is intended to address the mechanism behind approximately 80% of ACL (and maybe MCL) injuries, so it doesn't eliminate those injuries, just as standard bindings don't eliminate tibia fractures, but has reduced them to a significant degree. Howell has developed new measuring techniques which he feels are relevant and useful but the real question is, what degree his measurements and designs will correlate with ACL injury rates. As far as I know, the ongoing studies on ski safety do not address specific binding designs. Even if one could measure the numerator (number of skiers injured correlated with binding used), how would you determine the denominator (number of skiers on the hill with a specific binding design) so as to get a reliable injury percentage?
We do know that measurement protocols that Howell and others designed in the past did correlate with reductions in fractures, and apparently other researchers are working on duplicating and/or extending his research, so there appears to be hope for the future. And it is always a good thing when more than one researcher/engineer comes to the same conclusions, particularly if they come at the problem from a different direction - it gives you more confidence in the conclusions.
As of right now, though, the only published data on reducing ACL injuries is from research from Johnson, Shealy and Ettlinger, and focuses on training skiers to avoid high risk behaviors and correct high risk body positions. That has been shown to reduce ACL injuries by around 70-80%.
