A return to "the Kickstand Effect". So your foot is turned out, externally rotated ?

Amputee War Veteran Sergeant Christopher Melendez Became a Pro Wrestler
Read more at http://www.craveonline.com/mandatory/1053779-standing-tall-how-amputee-war-veteran-christopher-melendez-beca#XeD2LrZ2xmtXQ6um.99

Why is my foot turned out ?  A 3rd return to the solitary externally rotated foot.

Below you will find our 2 prior articles on this topic, but this is a relatable concept to other thing which we have embedded in many of our blog posts and podcasts over the last decade of sharing what we know.

In the photo above the brave Army Veteran Sergeant Melendez one can see the concept brilliantly as he only has one limb.  One can see the concept in full play, he must balance his body mass over one point, not two like the rest of us lucky folk.  In trying to balance over one point, if the foot is straight forward (if one is blessed with close to neutral torsional bone alignment) one will have good stability in the sagittal plane (forward /back) but will be at risk to fall, drift or sway into the frontal plane. Here Sergeant Melendez displays the foot and limb turn out into the frontal plane so that he can use the quadriceps to help him protect into that frontal plane, plus, by situating his base posture in more of an externally rotated position (likely losing internal rotation capability over time, unless forcibly maintained through specific exercises) he can more fully and skillfully engage all 3 divisions of the gluteus maximus and medius, and perhaps hamstrings and adductors and who knows what else, to maintain a more stable and likely less fatiguable posture. Go ahead, try it for yourself, this is easier to balance and maintain that a straight sagittal foot posturing. The one trouble he might have, is not deviating too much, or too often, into a frontal plane drift hip-pelvis posture. This will put much aberrant compressive load onto the roof of the femoral head-acetabular interval, where most of us begin a degenerative hip arthritis journey, unfortunately. 

Side note:   So you might think your client has FAI ?  Maybe start here, our thinking might lead you done a helpful path to get started. Search our blog for FAI as well.

here are the 2 prior articles on the topic, with video.  Watch for this one, it is everywhere out in the world, walking amongst us.  
Thank you for your service Sergeant Melendez.  Here is the article written by K. Thor Jensen, on Crave Online.  

https://thegaitguys.tumblr.com/post/14262793786/gait-problem-the-solitary-externally-rotated

https://thegaitguys.tumblr.com/post/40617674450/a-return-to-the-solitary-externally-rotated-foot

Shawn & Ivo, The Gait Guys