Which Measurements Matter to Patients?

“When faced with a difficult question, we often answer an easier one instead, usually without noticing the substitution.” -Daniel Kahneman

As physical therapists we have many tools to track patient progress; outcome surveys, range of motion measurements, etc. However, which of these measurements meaningfully reflect patient outcomes?

This might seem obvious. But we often forget to ask these big picture questions in the clinic. We also forget such questions when reading research or choosing con-ed courses.

To pick the right measurements, we need to understand “clinical endpoints“. This term comes from clinical medicine trials. A clinical endpoint is “an event or outcome that can be measured objectively to determine whether the intervention being studied is beneficial”.1

There are three types of clinical endpoints2:

1. Direct clinical endpoints
These directly relate to patient outcomes. For example, consider a soccer player with knee pain. A direct clinical end point would be their ability to play soccer with an acceptable level of pain. We could measure that with the Victorian Institute of Sport Assessment–Patella (VISA-P). An improvement in the VISA-P likely means an improved ability to play soccer with an acceptable level of pain.

Of course, direct clinical endpoints are not the only meaningful measurements. But they most directly relate to patient outcomes.

2. Surrogate endpoints
These predict patient outcomes. We use these if we can’t directly measure an outcome. For example, we don’t know whether an elderly patient will fall – until they fall. But a measure like the modified 30-second Sit to Stand (m30STS) predicts fall risk.3 If we improve the patient’s m30STS score, they should be at a lower risk of falling.

A surrogate endpoint should be validated. Meaning that data supports its ability to predict an outcome.2

However, some surrogate endpoints are not validated. Such endpoints theoretically relate to an outcome. But data doesn’t show that connection. For example, consider the elderly patient at risk of falling. Low calf muscle strength might correlate with falls. However, there are many other factors related to fall risk, so we can’t predict fall risk with calf muscle strength alone.

3. Biomarkers
These correlate with biological activity in a patient. They are least relevant to patient outcomes. For example, a PT might use a tool shown to “increase blood flow” in a patient with low back pain. “Increased blood flow” is a biomarker. This biomarker might correlate with tissue healing. And tissue healing might decrease low back pain. But this is a weak connection. The increased blood flow is an interesting effect, but may not be relevant to improving low back pain.


As we see, clinical endpoints are not all equally relevant. Understanding them is crucial to interpreting research findings, picking con-ed courses, and tracking patient progress. The goal is to not forget the goal: getting patients back to activities they love.

References:

  1. NCI Dictionary of Cancer Terms. (n.d.). Retrieved November 13, 2020, from https://www.cancer.gov/publications/dictionaries/cancer-terms/def/endpoint
  2. Sullivan, E. (n.d.). Clinical Trial Endpoints [Powerpoint slides]. Retrieved November 13, 2020 from https://www.fda.gov/media/84987/download
  3. Applebaum, E. V., Breton, D., Feng, Z. W., Ta, A. T., Walsh, K., Chassé, K., & Robbins, S. M. (2017). Modified 30-second Sit to Stand test predicts falls in a cohort of institutionalized older veterans. PloS one12(5), e0176946. https://doi.org/10.1371/journal.pone.0176946

Is pain during rehab exercise “OK”?

*Medical Disclaimer: Please be advised, the information provided in this article is educational in nature and not meant to diagnose or treat any disease, illness, or condition. For individualized recommendations it is best to follow up with a licensed provider, like myself or another physical therapist.

A common concern among clinicians is when a patient experiences pain during exercise. Some clinicians rush to modify the exercise so that the patient has no pain whatsoever. Others ask the patient to describe the pain, trying to differentiate between muscle fatigue and nociceptive pain. And some say it’s just part of the rehab process.

Thankfully in the past couple of decades research has been building on this question. In 2017 Smith et al. did a systematic review trying to answer this question. Their review included studies that:

-Were randomized control trials that compared exercise where pain was allowed/tolerated vs exercise that was pain-free
-Had adults with chronic musculoskeletal pain (defined as >3 months)
-Measured pain, disability, or function

*Note that adults with “non-musculoskeletal pain” were excluded (this list ranged from cancer to headaches to fibromyalgia).

From their search, 7 studies made the cut: 1 trial on low back pain, 3 trials on shoulder pain, and 3 trials on foot/ankle pain. Patients in the studies were instructed that pain during exercise was acceptable (in some studies up to even 5/10 on the VAS), but that the pain should subside afterwards.

They then analyzed the effectiveness in the short (<3 months), medium (3-6 months), and long term (>12 months).

The results?

– Short term, patients who had pain during exercise had statistically significantly LOWER pain scores compared to pain-free exercise
-Reductions in pain levels were similar in the medium and long term between groups
-Improvements in disability and function were similar in the short, medium, and long term between groups

In short, for patients with chronic pain, pain-free exercises and exercises where pain was allowed resulted in similar outcomes (though short term, exercises where pain was allowed led to significantly decreased pain levels). However, we still don’t know about acute injury and post-surgical patients. We likely have to rely on clinical judgement for this. Also, the research doesn’t address other regions of the body (knee, elbow, neck, etc), but I think that we can reasonably generalize the results to other regions of the body-it is likely that chronic pain responds similarly to treatment, regardless of the region of the body. Lastly, a major limitation is that patients with conditions like fibromyalgia and migraine were excluded-this is a major group of patients who suffer from chronic pain! It would be helpful to examine the effects of painful exercise in these populations.

A few questions remain for me:
-Is there a ceiling on the “allowable pain” during exercise? Is there a point of “too much” pain?
-Related, is pain post-exercise “OK”? Would patients have better or worse outcomes if the pain from exercise lingered for a couple days?
-After discharge from therapy if a patient experiences pain with general exercise (a general training program), does this predict future pain?

Here is the original paper for review: https://bjsm.bmj.com/content/51/23/1679

Temporomandibular Joint Pain: Why, What, and How

The temporomandibular joint (TMJ) is a small joint that can be the source of major pain in patients. While some TMJ pain is directly from the joint itself, there are MANY other causes of pain in this region and there are many treatments available. This presentation was given to clinicians as a primer on fundamental anatomy of the joint and how to evaluate TMJ pain.

A Primer on Pain Neuroscience Education and Chronic Pain

Pain science is becoming an increasingly prominent and sometimes controversial topic in PT. This is a presentation I gave for clinicians on models of pain and how to integrate pain neuroscience education into clinical practice.

Some say that pain science is just the latest fad in PT. However, pain science is not a “new treatment method”. Rather it is an extension of a holistic view of pain that acknowledges that the experience of pain is related to much more than just tissue damage.