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How effective is an evidence-based exercise intervention in individuals with patellofemoral pain?

PainSci » bibliography » Greaves et al 2021
Tags: patellar pain, strength, running, arthritis, aging, pain problems, knee, leg, limbs, overuse injury, injury, exercise, self-treatment, treatment

PainSci commentary on Greaves 2021: ?This page is one of thousands in the bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

Twenty-seven people with mild patellofemoral (kneecap) pain went through “a comprehensive rehabilitation programme” with the best options cooked up by a panel of experts in 2016: mostly exercise, especially hip and knee strengthening. This program is clearly not a “cure” — it’s just an example of the best anyone can recommend. It consists mostly of exercise, especially hip and knee strengthening.

And this wasn’t a real trial of the program. A true test would be a “controlled” trial, comparing the program to something else while eliminating as many variables as possible. Instead, they just watched, measured, and took notes (an “observational study”). The point was to learn something about the effect of the programme on running form, strength, function, and pain.

Only sixteen subjects finished the program. Their pain barely improved, despite being minor to begin with. The change was statistically insignificant by one standard way of measuring pain, and just barely by another.

Their function also improved, but also in underwhelming ways. For instance, fear of movement also barely improved, and how much more “functional” can you be without that?

These small wins for pain and function notably came without any improvement at all in running biomechanics and quads strength — and yet these are the main things that most professionals would say are the drivers of improvements in pain and function. This makes the result a bit of an eyebrow raiser.

One possible implication of this data is that you don’t have to get stronger or “fix” your running biomechanics to make some progress.

Another take-home message: that program really didn’t do much for minor cases. Improvement? Yes. Impressive? Hardly. But, again, it wasn’t a proper test. Observational studies are almost like high quality anecdotal evidence: they can provide reasons to study things more carefully, but that’s about it.

~ Paul Ingraham

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

OBJECTIVES: Guidelines for a comprehensive rehabilitation programme for patellofemoral pain (PFP) have been developed by international experts. The aim of this study was to analyse the effect of such a rehabilitative exercise programme on pain, function, kinesiophobia, running biomechanics, quadriceps strength and quadriceps muscle inhibition in individuals with PFP.

DESIGN: Observational study.

SETTING: Clinical environment.

PARTICIPANTS: Twenty-seven participants with PFP.

MAIN OUTCOME MEASURES: Symptoms [numeric pain rating scale (NPRS)and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS)], function measured by using the KUJALA scale and KOOS, kinesiophobia measured by using the Tampa scale, three-dimensional biomechanical running data, quadriceps isometric, concentric and eccentric strength and arthrogenic muscle inhibition (AMI) were acquired before and after the six-week exercise programme.

RESULTS: Although pain did not significantly improve all patients were pain-free after the six-week exercise programme (NPRS: p = 0.074). Function, kinesiophobia and quadriceps AMI improved significantly after the six-week exercise programme (KUJALA: p = 0.001, KOOS: p = 0.0001, Tampa: p = 0.017, AMI: p = 0.018). Running biomechanics during stance phase did not change after the exercise intervention. Quadriceps strength was not different after the six-week exercise programme (isometric: p = 0.992, concentric: p = 0.075, eccentric: p = 0.351).

CONCLUSION: The results of this study demonstrate that the current exercise recommendations can «modestly» improve function and kinesiophobia and reduce pain and AMI in individuals with «mild» PFP. There is a need for reconsideration of the current exercise guidelines in stronger individuals with PFP.

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