People clearly have differing ideas, but, even when presented with the same information, people can interpret it differently based on their currently-held worldview. Here is the most classic example I can come up with in terms orthopedic thinking: shoulder impingement. The predominant worldview (in the US at least) is that muscles, joints, tendons, and neural patterns around the shoulder are functioning improperly as a unit and therefore during overhead movements the subacromial space is impinged causing pain. My view is that in over 90% of cases one specific thing is not working correctly.

The prevailing treatment for the common worldview is simultaneously stretching or releasing one or more muscles, loading certain tendons, strengthening many muscles, and moving certain joints. I remember I used to give patients at least seven things to do at one time when I had that belief system, which I was taught.

My current view is that most patients need to move just one particular joint or tendon. That particular movement is often, but not always, included in the array of movements listed above, which is interesting but not surprising since the normal treatment includes so many things! So if people get better with the standard approach, people believe it’s correct.

My understanding now, however, is that the reason they got better is because they included the one thing they needed - and the rest was superfluous and, at worst, a waste of time and resources. My patients with shoulder pain with overhead movements almost always get just one exercise to do at a time, which may or may not change over time. (For me, what other clinicians diagnose as shoulder impingement, I diagnose as several different things: cervical derangement, thoracic derangement, shoulder derangement, and shoulder contractile dysfunction.)
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It’s interesting to think about how our belief systems can inform how we understand the evidence. Clearly those who believe the predominant worldview and those who believe the MDT-leaning view interpret the fact that people get better with standard shoulder impingement treatment very differently. As I wrote recently: I am interested in what works, but I’m more interested in what works best. - -Laura

I remember thinking years ago how odd it seemed that people’s joint pain (often occurring for no known reason) would be addressed by simultaneously stretching muscles, moving joints, strengthening other muscles, and changing posture (plus ice, heat, US, etc). It didn’t seem logical that all of those pieces fell perfectly into disarray, leading to pain.

Does it make more sense that joint immobility and muscle tightness and weakness led to the impingement, or that the impingement led to those findings? What I find more rational is that a joint impingement, a joint derangement, or, simply put, a joint that’s a bit stuck occurs because, well, joints are mobile things and these things happen. The most obvious example is you unknowingly sleep in a certain position and you wake up with stuck neck joints. Or your shoulder joint gets impinged because you repeatedly move in a new way starting tennis again. Or your low back gets deranged because you sit in the exact same position in your office chair for hours a day. These factors and others can easily lead to minor (fixable!) joint disruptions. In fact, most of these examples, especially the neck scenario, will resolve with daily movement (and possibly a little rest) on their own - no doctors or other help needed.

I deduce in the clinic if a joint is impinged/not moving optimally by repeatedly moving joints and gauging the effect. I don’t rely on “impingement tests.” I secondly don’t believe in the value of imaging except for a small minority of cases. It’s much more likely that the bony configuration of your joint (eg shoulder acromion or hip acetabulum) has been that way, if not your entire life, then most of your life, and therefore this new pain is due to new factors.

To address it, in contrast to the stretching, strengthening, and movement I alluded to above, we look for the specific joint movement that unpinches the joint. It’s typically one that is not regularly performed in the person’s daily life. The theory as to why these things occur is that it’s normal for joints to get a bit stuck if you don’t move them in a variety of directions or if you spend the majority of your time in one uninterrupted direction. They’re so common that most self resolve, but I see the stubborn ones. -- Laura