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

BackgroundCentral 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. MethodsThirty 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. ResultsWomen 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 (r(2) = 0.426, P < 0.05), painDETECT questionnaire (r(2) = 0.394, P < 0.05), and Pain Catastrophizing Scale (r(2) = 0.413, P < 0.05), and with lower PPTs at the thenar eminence (r(2) = -0.410, P < 0.05), vastus lateralis (r(2) = -0.530, P < 0.01), vastus medialis (r(2) = 0.363, P < 0.05), and greater trochanter (r(2) = -0.373, P < 0.05). ConclusionsGreater 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.