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A meta-analysis of very little data on the reliability of finding trigger points by feel

PainSci » bibliography » Rathbone et al 2017
updated
Tags: massage, trigger points doubts, diagnosis, muscle pain, chronic pain, back pain, manual therapy, treatment, muscle, pain problems, spine

Five articles on PainSci cite Rathbone 2017: 1. Does Massage Therapy Work?2. The Complete Guide to Trigger Points & Myofascial Pain3. Complete Guide to Low Back Pain4. Is Diagnosis for Pain Problems Reliable?5. Trigger Point Doubts

PainSci summary of Rathbone 2017: ?This page is one of thousands in the PainScience.com 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.

This is a meta-analysis of 6 studies of how much different experts can agree on the location of myofascial trigger points (inter-rater reliability). They had to “estimate” an agreement score of 𝛋=0.452 — a rather precise estimate! Of the criteria used to determine the location of trigger points, the most reliable were localized tenderness (.68) and pain recognition (.57).

Those are actually not terrible reliability scores. Obviously they could be better, and it would be nice if they were, but it’s important context that most attempts to detect pathologies in the body are technically “unreliable,” falling well short of a score of κ=1.0 (perfect agreement), but still much better than κ=0 (coin flipping agreement).

And the error bars on those estimates were too large for a confident conclusion anyway.

Therefore, my conclusion is that this review was mostly inconclusive, but actually found evidence that trigger point reliability is probably not all that bad (compared to what you’d expect from a diagnostic procedure for something that doesn’t actually exist).

~ 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.

OBJECTIVE: To achieve a statistical estimate of the agreement of manual palpation for identification of myofascial trigger points (MTrPs) and secondarily to investigate potential factors impacting the agreement of this technique.

METHODS: We searched MEDLINE(R) and Embase for studies examining the reproducibility of manual palpation for the identification of MTrPs from the year 2007 to present. In addition, we utilized studies identified by 2 comprehensive systematic reviews that covered the period before 2007. The included studies were original peer-reviewed research articles and included Cohen κ measures or data with which to calculate Cohen κ. Studies were excluded if they lacked a measure of variability or information required to calculate variability. Studies that examined palpation through body cavities were also excluded. Of the 18 potentially relevant articles only 6 met inclusion criteria including 363 patients. Modified QUADAS tool was used to assess study validity. Subgroup comparisons were made utilizing Q and Z tests.

RESULTS: An estimate of κ=0.452 (95% confidence interval, 0.364-0.540) was obtained for interrater agreement of manual palpation of MTrPs. Localized tenderness (κ=0.676) and pain recognition (κ=0.575) were the most reliable criteria. Only 1 study met inclusion criteria for intrarater agreement and therefore no meta-analysis was performed.

DISCUSSION: Use of manual palpation for identification of MTrPs is unreliable, and future investigation should focus on integration with more reliable techniques.

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