No evidence linking injuries to a dysfunctional tensor fascia latae muscle
One article on PainSci cites Besomi 2020: The Complete Guide to IT Band Syndrome
PainSci commentary on Besomi 2020: ?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.
It’s a common idea in musculoskeletal medicine that muscles can be “dysfunctional,” boosting injury risk over time, and otherwise letting us down. Dysfunction of the tensor fascia latae (TFL) muscle is one of the more usual suspects, often blamed for contributing to several hip and knee injuries and issues, but mostly iliotibial band syndrome, greater trochanteric pain syndrome, and patellofemoral syndrome.
Besomi et al reviewed seventeen studies of the TFL in people both with and without several conditions (in addition to the above, hip joint arthritis and knee ligament tears). Eight of the studies were of the size of the TFL (“structure”), and ten were studies of its electrical activity while contracting (“activation”).
They found a handful of minor, uninformative differences in these measurements — which is utterly unsurprising. There are a few reasons why I wouldn’t ever expect such studies to shed much light on anything.
Above all, muscle “dysfunction” is a really poorly defined concept. Activation and size are just a couple things about a muscle that we can easily measure, “looking where the light is,” but without dramatic differences they are unlikely to tell us anything about how well the muscle is working. There are other ways that a muscle could plausibly be dysfunctional which were not considered by these studies at all.
Also, some of these studies were looking for more implausible links with other injuries. It’s a bit of a reach to blame the TFL for anything at all, but knee ligament tears? Hip arthritis? Come on. I would be shocked if those conditions were TFL-sensitive.
Even when the research flashlight is aimed at a condition with a more plausible link — like Baker et al did, studying the TFL-ITBS link specifically — there’s hardly a smoking gun there either. They found essentially nothing.
Besomi et al reasonably concluded that the “common clinical assumptions” about the TFL’s role in injury are “not well investigated and poorly supported.” Indeed! These kinds of ideas have always just been speculative, just professionals spitballing about how muscles and joints work. Most of them have yet to be studied at all, let alone well.
There is maybe one slightly useful thing this study can tell us: apparently there is nothing terribly obvious wrong with the TFL in people with these injuries, or it probably would have shown up in the seventeen studies reviewed. But that’s kind of like saying “if bigfoot was as tall as King Kong, he would have been found ages ago.”
Bottom line: No one really has any idea if there’s any such thing as a glitchy tensor fascia latae, let alone whether it causes injuries, and this paper does not shed any significant light on this topic.
~ Paul Ingraham
Common issues and characteristics relevant to this paper: ?Scientific papers have many common characteristics, flaws, and limitations, and many of these are rarely or never acknowledged in the paper itself, or even by other reviewers. I have reviewed thousands of papers, and described many of these issues literally hundreds of times. Eventually I got sick of repeating myself, and so now I just refer to a list common characteristics, especially flaws. Not every single one of them applies perfectly to every paper, but if something is listed here, it is relevant in some way. Note that in the case of reviews, the issue may apply to the science being reviewed, and not the review itself.
- Paper points to an “absence of evidence” rather than “evidence of absence,” which is just a fancy way of saying “inconclusive.”
- Garbage in, garbage out — not enough good quality data to meaningfully review/analyze.
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.
BACKGROUND: Dysfunction of the tensor fascia latae (TFL) muscle is often clinically implicated in many musculoskeletal disorders.
OBJECTIVE: To systematically review the literature of the TFL muscle to determine whether there are differences in its structure and activation between individuals with and without lower limb musculoskeletal conditions.
DATA SOURCES: A comprehensive search in MEDLINE, EMBASE, CINHAL, and LILACS was undertaken from year of inception to 9 July 2019.
ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies that directly investigated the structure or activity of the TFL muscle between individuals with a lower limb musculoskeletal condition and a pain-free control group.
RESULTS: Seventeen studies were included (n = 556 participants), eight reporting structure and ten activation of the TFL muscle. Conditions included lateral hip pain, hip joint pathology, ACL injury, iliotibial band syndrome, and patellofemoral joint osteoarthritis. Meta-analysis identified with low confidence (p value = 0.07) a small tendency towards hypertrophy in the affected side of participants with hip joint diseases (SMD 0.37, 95% CI [- 0.02, 0.77]). Moderate effect sizes were found for a higher cross-sectional area of the TFL/sartorius ratio in abductor tendon tear (SMD 0.74; 95% CI [0.05, 1.43, p value = 0.04), and for a smaller body mass normalized TFL volume in patellofemoral joint osteoarthritis (SMD - 0.61; 95% CI [- 1.23, 0.00], p value = 0.05). Normalised electromyography (EMG) amplitude did not differ between groups for any condition, but when EMG was analysed as linear envelopes or synergies, some differences in pattern of TFL activation were observed between individuals with lateral hip pain and controls. Timing of TFL activation did not differ between individuals with knee conditions and controls.
CONCLUSIONS AND IMPLICATIONS: Common clinical assumptions of the role of TFL muscle in lower limb musculoskeletal conditions are not well investigated and poorly supported by current research. There are contradictory findings on the muscle size of TFL. Differing methodology in muscle activation studies precludes a clear interpretation for comparison between groups.
- “Differences in Knee and Hip Adduction and Hip Muscle Activation in Runners With and Without Iliotibial Band Syndrome,” Baker et al, PM & R: The Journal of Injury, Function, and Rehabilitation, 2018.
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- Inciting events associated with lumbar disc herniation. Suri 2010 Spine J.
- Prediction of an extruded fragment in lumbar disc patients from clinical presentations. Pople 1994 Spine (Phila Pa 1976).
- Characteristics of patients with low back and leg pain seeking treatment in primary care: baseline results from the ATLAS cohort study. Konstantinou 2015 BMC Musculoskelet Disord.
- Effectiveness and cost-effectiveness of universal school-based mindfulness training compared with normal school provision in reducing risk of mental health problems and promoting well-being in adolescence: the MYRIAD cluster randomised controlled trial. Kuyken 2022 Evid Based Ment Health.
- No long-term effects after a three-week open-label placebo treatment for chronic low back pain: a three-year follow-up of a randomized controlled trial. Kleine-Borgmann 2022 Pain.