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In more than 2000 people with knee osteoarthritis, or at high risk for it, pain sensitization was associated with knee pain, but not the severity of arthritis as seen on x-ray. Neither pain nor sensitivity clearly correlated with the condition of their knee.
This contradicted the researchers’ expectation that sensitization is driven by the duration and severity of arthritis. Instead, the results suggest t:
sensitization is in fact a ‘trait’ rather than a ‘state’, that is, that hypersensitivity was present before knee osteoarthritis, related to an individual’s predisposition to sensitization rather than being induced by peripheral nociceptive input [pain] from osteoarthritis.
Even more simply stated: people with knee pain have a problem with pain itself, not knees, to at least some extent.
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: It is not clear whether heightened pain sensitivity in knee osteoarthritis (OA) is related to sensitisation induced by nociceptive input from OA pathology ('state') versus other confounding factors. Conversely, some individuals may be predisposed to sensitisation irrespective of OA ('trait').
METHODS: The Multicenter Osteoarthritis Study is a longitudinal cohort of persons with or at risk of knee OA. We obtained knee X-rays, pain questionnaires and comprehensive assessment of factors that can influence pain sensitivity. We examined the relation of sensitisation and sensitivity assessed by mechanical temporal summation (TS) and pressure pain thresholds (PPTs) to knee OA and knee pain severity. To test whether sensitisation and sensitivity is a 'state' induced by OA pathology, we examined the relation of PPT and TS to knee OA duration and severity.
RESULTS: In 2126 subjects (mean age 68, mean body mass index (BMI) 31, 61% female), PPT and TS were not associated with radiographic OA (ORs 0.9-1.0 for PPT and TS; p>0.05). However, PPT and TS were associated with pain severity (ORs: 1.7-2.0 for PPT; 1.3-1.6 for TS; p<0.05). Knee OA duration and radiographic severity were not associated with PPT or TS.
CONCLUSIONS: PPT and TS were associated with OA-related pain, but not radiographic OA after accounting for pertinent confounders in this large cohort. Lack of association with disease duration suggests at least some sensitisation and pain sensitivity may be a trait rather than state. Understanding the relationship between pathological pain and pain sensitivity/sensitisation offers insight into OA pain risk factors and pain management opportunities.
These two articles on PainScience.com cite Neogi 2015 as a source:
- PS Repetitive Strain Injuries Tutorial — Five surprising and important facts about repetitive strain injuries like carpal tunnel syndrome, tendinitis, or iliotibial band syndrome
- PS Do IT Band Straps Work for Runner’s Knee? — The science of knee straps for iliotibial band syndrome (runner’s knee)
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:
- Effectiveness of customised foot orthoses for Achilles tendinopathy: a randomised controlled trial. Munteanu 2015 Br J Sports Med.
- A Bayesian model-averaged meta-analysis of the power pose effect with informed and default priors: the case of felt power. Gronau 2017 Comprehensive Results in Social Psychology.
- The neck and headaches. Bogduk 2014 Neurol Clin.
- Agreement of self-reported items and clinically assessed nerve root involvement (or sciatica) in a primary care setting. Konstantinou 2012 Eur Spine J.
- Effect of NSAIDs on Recovery From Acute Skeletal Muscle Injury: A Systematic Review and Meta-analysis. Morelli 2017 Am J Sports Med.