The concept of specific therapy being done on specific structures has been debated for some time now. For years we were sure that we could palpate and do manual therapy on specific vertebrae, we were sure we were targeting the anteromedial fibers of the supraspinatus tendon for shoulder pain, and we were fixing millimeters of leg length discrepancy. More and more research suggests that a large part of a patient navigating a pain experience has very little to do with specific effects, and instead the environment and perception of a condition mediates the response.
Would it be easier to identify 1 of 1,000 reasons a patient might get better? Is it ever really just one exercise, stretch, or treatment that gets someone better? Or is it a blend of extrinsic and intrinsic factors, physiology, psychology, and many other factors that elicit progress?
The illusion of specificity is the idea that a specific treatment directly elicits the outcome. Some of the more prominent diagnoses and treatments were founded on being specific; as it should be, right? Trigger points were thought to be able to be identified by palpation. Manual therapy was thought to be able to be applied to a specific vertebral segment. Years and years of clinicians taking credit for the things our hands felt and did.
“The illusion of specificity is the idea that a specific treatment directly elicits the outcome.”
How have these rehabilitative paradigms held up in research? In short, not well. Trigger points cannot reliably be identified without input from the patient, simply poking and feeling tissue cannot locate them.1 One study reported that interrater reliability of sacroiliac motion is more reliable when done by chiropractic students than by seasoned clinicians, but both have very low kappa values, no better than chance.2 Furthermore, for patients with non-specific low back pain, targeting a specific vertebral level did not result in improved outcomes on pain intensity and patient-reported disability compared to a non-targeted approach.3
If we revisit that last paragraph, you can see that things like “specific manual therapy” and “non-specific low back pain” probably have a hard time getting along as it is. It would be like calling out a corner pocket while playing pool in the dark, as confident as it is difficult. There are overlapping fallacies at play; first, the ability to palpate intervertebral movement reliably and consistently to identify a certain level; second, the idea that a specific anatomic structure in isolation is responsible for the pain a person is experiencing, and last, the idea that one single stimulus is the sole predictor of the response.
The illusion of specificity is an easy trap to fall into, especially as a new grad or young clinician. The Dunning-Kreuger Effect highlights this, with peaks and valleys of the relationship between knowledge and confidence. Ranging from an “I know everything” phase early in a career, falling to an “I know nothing,” and eventually to a “plateau of sustainability.” I’m sure we as clinicians have felt all of these, either over the course of a career or sometimes even within the same day.
So, if we have accepted the fact that there are many different treatment options for someone to get better, and often the improvement cannot be attributed to a single treatment or exercise, has physiology taken a back seat to affect? Are we all just happy-go-lucky patients whose back pain goes away with better sleep and less stress? If I win the lottery, does my shoulder pain just vanish? Even though the lottery would only pay back about half of my student loans, it sure would help my knees bend easier to be honest.
It’s not that complex, but it’s not that simple. To break this down, we must honor peripheral and central mechanisms. Is someone with subacromial pain syndrome likely to have noxious stimuli to the muscles of the shoulder? Absolutely, the physical demands of this person’s life exceed the physiologic properties of the tissue. You have to let wet towels dry. This person would likely benefit from strengthening of the shoulder and isometrics for periodic pain relief during the day. Sounds easy enough, right?
However, we’ve all seen the perfect candidate not respond and get better, and some patients get better much quicker than they should. This same patient is likely in a mental state of worry and concern over their condition, and they have anxieties, preconceived notions, beliefs about their condition, prior healthcare/rehabilitation experiences, and many other variables around their current state. Even the way I introduce myself, the clinic environment, reputation, shoot, even if I’ve just gotten a fresh haircut can all affect the way my patients respond to treatment. One of the many mediating factors for the physiology behind contextual effects is the hypothalamic pituitary axis (HPA) and stress hormones.1 Such a quick change in presentation likely does not allow the time for structural changes in the tendon or structure itself. Instead, can a change in regulation of the nervous system drive modulating factors within the joint itself? Isn’t this the very hallmark of the therapeutic alliance? Forming a bond between patient and clinician reaches deeper than knowing they like to go hiking or what TV shows they like; it means they know you care about them. That alone can have those physiologic ramifications that get the ball rolling.
In a world of “if, then,” it is fair game to think that one thing directly impacts the other. If I’m a patient and I eat a ham sandwich one day and my back feels good, you better believe I’m eating that same sandwich every day. We all know joint pathology is complicated, however, the human being it is attached to is way more complicated. Trying to pinpoint a specific effect is not only unreliable, but it is alleviating to us as clinicians. The constant evaluating and re-evaluating can get exhausting, especially with a tricky patient. It takes the pressure off our hands and exercise prescription, and instead re-emphasizes the individuality of our therapy to a patient. Allowing space for multiple influences to mediate a response is contemporary physical therapy, and it is important we be aware that while we aim to help every patient, it is not always solely what we do that gets it done.
What we do is an art. Like cooking, we take a blend of things together and create something meaningful. For each patient, no matter how complicated the joint or body part we are treating may be, the person it is connected to is likely way more complicated. It is nearly impossible to link one treatment to an outcome, and instead we must be aware of the multitude of other factors that can impact a patient’s recovery, both inside and outside of the clinic.
References
1. Quintner JL, Bove GM, Cohen ML. A critical evaluation of the trigger point phenomenon. Rheumatology (Oxford). 2015;54(3):392-399. doi:10.1093/rheumatology/keu471
2. Mior SA, McGregor M, Schut B. The role of experience in clinical accuracy. J Manipulative Physiol Ther. 1990;13(2):68-71.
3. Sørensen PW, Nim CG, Poulsen E, Juhl CB. Spinal manipulative therapy for non-specific low back pain - does targeting a specific vertebral level make a difference?: A systematic review with meta-analysis. J Orthop Sports Phys Ther. 2023:1-30. doi:10.2519/jospt.2023.11962
4. McBeth J, Chiu YH, Silman AJ, Ray D, et al. Hypothalamic-pituitary-adrenal stress axis function and the relationship with chronic widespread pain and its antecedents. Arthritis Res Ther. 2005;7(5):R992-R1000. doi:10.1186/ar1772
The author declares no competing interests.
Author Bio:
Nicholas Munro, PT, DPT, OCS is a physical therapist in Syracuse, NY passionate about patient self-efficacy, contemporary practice, and advocating for effective patient management. He received his DPT from Utica University in 2019 and became a board-certified orthopaedic specialist in 2022. He has been involved in local community outreach programs and is helping to develop wellness programs to bring another outlet for physical fitness in the community. Outside of the clinic, he is enthusiastic about keeping a physically active lifestyle with his girlfriend and playing with their cat, Archie.