The Extent of Pain Is Associated With Signs of Central Sensitization in Patients With Hip Osteoarthritis

Abstract

Background Central sensitization may be present in some patients with hip osteoarthritis (OA), often reflected as widespread pain. We examine the association between pain extent with signs of central sensitization and other clinical and psychological features in patients with hip OA. Methods Thirty patients with hip OA were recruited for this cross‐sectional observational study. Participants completed pain drawings on a digital tablet, which displayed frontal and dorsal views of the body. The pain extent (%) for each participant was determined by combining the frontal and dorsal pixels shaded and dividing by the total pixels of the body chart area. Participants completed patient‐reported outcome measures to assess for signs and symptoms of central sensitization and psychosocial factors. Quantitative sensory testing including pain pressure thresholds (PPTs) and thermal pressure thresholds was performed at points anatomically local and distant from the hip. Results Women had significantly greater pain extent (6.71%) than men (2.65%) (z = −2.76, P < 0.01). Across all participants, increased pain extent was significantly associated with higher scores on the Widespread Pain Index (r2 = 0.426, P < 0.05), painDETECT questionnaire (r2 = 0.394, P < 0.05), and Pain Catastrophizing Scale (r2 = 0.413, P < 0.05), and with lower PPTs at the thenar eminence (r2 = −0.410, P < 0.05), vastus lateralis (r2 = −0.530, P < 0.01), vastus medialis (r2 = 0.363, P < 0.05), and greater trochanter (r2 = −0.373, P < 0.05). Conclusions Greater pain extent was associated with several measures of signs and symptoms of central sensitization in patients with hip OA. These results support the utility of the pain drawing for identifying signs of central sensitization in patients with hip OA.

Clinical Significance and Diagnostic Value of Pain Extent Extracted from Pain Drawings: A Scoping Review

“…From the thirteen studies that were examined, two were excluded, the first one because it included asymptomatic individuals [ 11 ], and the second one because it was a randomized controlled clinical trial [ 19 ]. A total of eleven cross-sectional cohort studies [ 10 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] were included in the final literature data mapping ( Figure 3 ).…”

“…All studies used digital software-based computation for calculating pain extent with six of them collecting data with digitalized PDs on a tablet [ 10 , 20 , 21 , 24 , 27 , 28 ] and five using a pen-to-paper approach [ 22 , 23 , 25 , 26 , 29 ]. Across all studies, the pain extent ranged from 6.7% to 22% (mean ± SD: 12.1% ± 5.3%), and in all cases its computation was software-based as per the inclusion criteria.…”

“…In addition, all studies included pain-related outcomes in the following domains: intensity, duration, pain-related disability and function. Psychological patient-reported outcome measures included depression ( n = 6) [ 21 , 22 , 25 , 27 , 28 , 29 ], anxiety ( n = 5) [ 21 , 22 , 25 , 27 , 28 ], kinesiophobia ( n = 4) [ 20 , 21 , 28 , 29 ] and catastrophism ( n = 3) [ 21 , 27 , 28 ]. Psycho-physical measures mostly included pressure and thermal thresholds.…”

“…Psycho-physical measures mostly included pressure and thermal thresholds. Pressure pain thresholds (PPTs) were assessed in seven studies in symptomatic and distant pain-free areas for assessing widespread pressure pain sensitivity [ 20 , 21 , 22 , 23 , 25 , 26 , 28 ], whereas thermal pain thresholds (cold pain, CPT and heat pain, HPT) were assessed in four studies [ 23 , 25 , 26 , 28 ]. Other measures, e.g., central sensitization inventory or conditioning pain modulation were also assessed, but only in one study [ 20 ] ( Table 2 ).…”

“…The methodological quality score was 3 stars (maximum score in cross-sectional cohort designs) in ten studies [ 10 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 28 , 29 ] and 2 stars in the last one [ 27 ]. No disagreement between authors was observed.…”