Activity-related pain predicts pain and functional outcomes in people with knee osteoarthritis: A longitudinal study

Abstract

Knee Osteoarthritis (OA) is a prevalent musculoskeletal condition, commonly resulting in pain and disability. However, pain and disability in this population are poorly related with the degree of structural joint damage. Underlying pain mechanisms, including activity-related pain and sensitization assessed via Quantitative Sensory Testing (QST), may better predict pain and functional outcomes of those with knee OA. Therefore, the aim of this study was to explore whether activity-related pain and sensitization assessed via QST predict future pain, function, fatigue, physical performance and quality of life outcomes in those living in the community with knee OA. Eighty-six participants with knee OA were recruited in Dunedin, New Zealand. Those eligible to participate underwent baseline testing including QST as well as measures of activity-related pain including Movement-evoked Pain (MEP) and Sensitivity to Physical Activity (SPA). Outcome measures exploring pain, function, fatigue and quality of life outcomes were collected at baseline, and two follow-up periods (two and nine weeks). Univariable linear regression models were developed followed by multivariable linear regression models for each prognostic marker adjusting for age, gender, BMI, OA duration, baseline pain intensity and socioeconomic status. Activity-related measures of pain, including MEP and SPA, demonstrated predictive associations with pain and functional outcomes prospectively in those with knee OA. Therefore, those demonstrating activity-related pain are at future risk of greater pain, disability and reduced quality of life. Larger, externally validated longitudinal studies are required which include individuals with more severe knee OA.

Activity-related pain and sensitization predict within- and between-person pain experience in people with knee osteoarthritis: An ecological momentary assessment study

“…SPA was calculated as the difference between prior and peak discomfort ratings [ 3 ]. Activity-related pain measures potentially provide a more ecologically valid measure of TS, with links to central sensitization, greater pain intensity and reduced functioning [ 3 , 5 ].…”

“…To analyse time-invariant outcomes collected via EMA (OA flare-up frequency) multiple adjusted linear regressions each including one sensitization predictor were completed using SPSS (Version 28.0.1.0). Models were adjusted for covariates including age, sex, BMI, OA symptom duration, baseline pain intensity and socioeconomic status [ 5 ]. Multicollinearity and heteroskedasticity were assessed for each analysis by examining multicollinearity statistics as well as scatterplots of residuals.…”

“…These changes have been demonstrated via Quantitative Sensory Testing (QST) in those with knee OA and include local and widespread pressure hyperalgesia, widespread cold hyperalgesia, heightened temporal summation (TS) and impaired descending modulation [ 2 ]. These QST measures have also demonstrated relationships with activity-related pain in those with knee OA [ [3] , [4] , [5] ]. Therefore, activity-related pain may also be a measure of nervous system sensitization which demonstrates ecological validity to living and functioning with painful knee OA [ [3] , [4] , [5] ].…”

“…These QST measures have also demonstrated relationships with activity-related pain in those with knee OA [ [3] , [4] , [5] ]. Therefore, activity-related pain may also be a measure of nervous system sensitization which demonstrates ecological validity to living and functioning with painful knee OA [ [3] , [4] , [5] ]. Nervous system sensitization (hereafter referred to as ‘sensitization’) has significant clinical consequences in individuals with knee OA.…”

“…Cross-sectionally, this includes greater pain intensity, disability and poorer quality of life on recall-based questionnaires [ 6 , 7 ]. Prospective studies have also been completed, demonstrating the predictive role of sensitization on worse knee OA outcomes as well as treatment responsiveness [ 5 , 8 , 9 ].…”