At one time I was able to work with an athlete who participated in sport requiring twisting of the torso while the feet are fixed to the ground. Upon introduction, they relayed skepticism about the ‘diagnosis’ being the problem of ‘cam impingement’ seen on a radiograph.
As we can see in the picture above the cam presented on the radiograph as bony deposit on the hip where the neck meets the ball. Immediately I considered ‘Wolff’s Law’ which states ‘that bone in a healthy person or animal will adapt to the loads under which it is placed’. So the question becomes, what is placing load on this region of the femur?
Watching this individual rotate his torso in a fixed feet position quickly revealed the answer. They could not rotate through their thoracic spine. As a result the pelvis had to move more to accommodate a reduction in mobility in the thoracic spine.
So let’s expound a bit. Baseball is the sport. A right handed hitter. During the wind-up, the pelvis was placing the right femur into a flexed and internally rotated position. The thoracic spine did not assist with rotation driven by the arms so the pelvis had to move more and faster. This in turn provided the load stimulus on the anterior femur. Wolff’s law then stated that bone will deposit in response to the load and as a result the formation of the ‘cam’ was the consequence.
Facilitating motion in the thoracic spine with functional integration lead almost immediately to increase in power production and reduction in hip pain.