Discordance between pain and radiographic severity in knee osteoarthritis: Findings from quantitative sensory testing of central sensitization

Abstract

Objective Radiographic measures of the pathologic changes of knee osteoarthritis (OA) have shown modest associations with clinical pain. We sought to evaluate possible differences in quantitative sensory testing (QST) results and psychosocial distress profiles between knee OA patients with discordant versus congruent clinical pain reports relative to radiographic severity measures. Methods A total of 113 participants (66.7% women; mean ± SD age 61.05 ± 8.93 years) with knee OA participated in the study. Radiographic evidence of joint pathology was graded according to the Kellgren/ Lawrence scale. Central sensitization was indexed through quantitative sensory testing, including heat and pressure–pain thresholds, tonic suprathreshold pain (cold pressor test), and repeated phasic suprathreshold mechanical and thermal pain. Subgroups were constructed by dichotomizing clinical knee pain scores (median split) and knee OA grade scores (grades 1–2 versus 3–4), resulting in 4 groups: low pain/low knee OA grade (n = 24), high pain/high knee OA grade (n = 32), low pain/high knee OA grade (n = 27), and high pain/low knee OA grade (n = 30). Results Multivariate analyses revealed significantly heightened pain sensitivity in the high pain/low knee OA grade group, while the low pain/high knee OA grade group was less pain-sensitive. Group differences remained significant after adjusting for differences on psychosocial measures, as well as age, sex, and race. Conclusion The results suggest that central sensitization in knee OA is especially apparent among patients with reports of high levels of clinical pain in the absence of moderate-to-severe radiographic evidence of pathologic changes of knee OA.

Is There a Possible Neuropathic Pain Component in Knee Osteoarthritis?

“…There are many patients who have radiographic evidence of OA in the absence of pain and those who have little radiographic evidence of OA with moderate to severe pain. 31 Finan et al 32 suggested that central sensitization in knee OA is apparent among patients with high levels of pain in the absence of moderate-to-severe radiographic evidence of knee OA. In our study, there was significant correlation between painDETECT scores and the VAS score, but we found no correlation between painDETECT scores and the Kellgren-Lawrence grades.…”

The sources of pain in osteoarthritis: a pathophysiological review

“…Pain is reported by 10% of subjects with normal radiographs, and 40-79% of patients with the significant radiographic joint abnormalities typical of OA (30). A number of studies indicate that only half of the patients with radiographic OA feel pain, and that there is a weak correlation between pain severity and radiographic changes (31)(32)(33)(34). Even studies showing significant associations between changes in joint structure and symptoms have found that 51% of the subjects with knee pain for >1 year do not show any typical radiographic joint changes, and that up to 50% of patients with the radiographic changes of OA have no symptoms (35).…”

Are Psychological Factors Associated with Pain Worsening in Individuals with Knee Osteoarthritis? A Systematic Review

“…Of eleven studies [14][15][16][17][18][19][20][21][22][23][24], six at least showed a significant relationship between depression and pain, but these findings corresponded to evidence level IV because they were confirmed by cross-sectional studies; the results of the two cohort studies were not consistent. Pain catastrophizing had been measured by ten studies [14,15,19,20,23,[25][26][27][28][29] in our review and was shown to be related with pain worsening in six cross-sectional studies as evidence level IV and in one prospective cohort study as evidence level II. Self-efficacy was significantly related to pain worsening in four studies [16,25,27,30], and one study suggesting this finding …”

“…RoBANS contains six domains: the selection of participants, confounding variables, the measurement of exposure, the blinding corresponded to evidence level II. Anxiety was investigated by five studies [14,18,19,28,31], one of these studies was of a prospective cohort design and showed no causal relationship with pain worsening. Three studies [19,26,28] examined the relationship with fear and pain worsening, but statistical significance was not confirmed.…”