Is Distribution of Pain Related with Central Sensitization in Patients with Lower Limb Osteoarthritis?

Abstract

Design: Cross-sectional study. Background: Osteoarthritis is one of the most common conditions in our society. A growing number of studies suggest the existence of central sensitization (CS) in a subgroup of osteoarthritic patients. One of the criteria included for the classification of CS pain is the expanded distribution of pain. As this criterion is a well-recognized sign of CS, a digital pain drawing (DPD) analysis would be useful to easily identify possible extended areas of pain distribution (PD) in patients with OA. Objective: To study the relationship between the percentage of distribution of pain in the lower limb for both knee and hip, in patients before hip or knee arthroplasty, and the Central Sensitization Inventory Questionnaire. Methods: Twenty women (mean age=64.78±9.5 years) with diagnosed chronic (over 3 months) knee (n=11) and hip (n=9) OA participated in the study, with intensity of pain from mild to severe, meaning pain >5/10 using the Numeric Pain Rating Scale (NPRS). The PD was analyzed via software created for this research, called "Pain Distribution Application". Results: A statistically significant positive correlation between CSI and PD to the lower extremity OA (hip and knee) (r=0.775, p<0.01) was found. The distribution of pain has a linear correlation with the results in CSI, of patients who tested positive for CS, i.e. with a score of ≥40. Conclusions: As the distribution of pain on the surface of the body (diffusion) increases, so does the score of people who test positive for CSI. Our results showed that calculating the distribution of pain with our application may have a utility as a CS screening tool. The PD threshold of 10% of the body area is an index for CS for chronic pain lower limb OA patients. © 2021 World Scientific Publishing Company.