The following is a summary of “Relation of pain sensitization to self-reported and performance-based measures of physical functioning: the Multicenter Osteoarthritis (MOST) study,” published in the June 2023 issue of Osteoarthritis and Cartilage by Corrigan et al.
It is unknown if changes in nociceptive signals are a factor in knee osteoarthritis (OA) patients’ impaired physical functionality. To better understand how pain sensitization affects physical functioning in those with knee OA or at risk for developing it, researchers examined whether knee pain intensity influences these associations.
The Multicenter Osteoarthritis Study, a cohort study of people with or at risk for knee OA, provided the cross-sectional data they used. Quantitative sensory testing evaluated the temporal summation (TS) and pressure pain thresholds (PPTs). The Western Ontario and McMaster Universities Arthritis Index function subscale (WOMAC-F) was used to measure self-reported function. During a 20-m stroll, the rate of walking was measured. Using dynamometry, the strength of knee extension was evaluated. The relationships between PPTs and TS and functional outcomes were investigated using linear regression. Mediation analyses were used to evaluate the knee pain severity’s mediating role.
Lower PPTs and the presence of TS were linked to worse WOMAC-F scores, slower walking speeds, and weaker knee extension among 1560 participants (60.5% female, mean age (SD) 67 (8), body mass index (BMI) 30.2 (5.5) kg/m2). There were differing degrees of knee pain intensity mediation, with performance-based function seeing the least mediation and self-report function seeing the most.
In people with or at risk for knee OA, increased pain sensitivity appears to be significantly correlated with weaker knee extension. Walking speed and self-reported physical function are not clinically significant relationships. Different levels of knee discomfort mediated these associations.