Experimental pain sensitivity differs as a function of clinical pain severity in symptomatic knee osteoarthritis

Abstract

Objective Pain in knee osteoarthritis (OA) has historically been attributed to peripheral pathophysiology; however, the poor correspondence between objective measures of disease severity and clinical symptoms suggests that non-local factors, such as altered central processing of painful stimuli, also contribute to clinical pain in knee OA. Consistent with this notion, recent evidence demonstrates that patients with knee OA exhibit increased sensitivity to painful stimuli at body sites unaffected by clinical pain. Design In order to further investigate the contribution of altered pain processing to knee OA pain, the current study tested the hypothesis that symptomatic knee OA is associated with enhanced sensitivity to experimental pain stimuli at the knee and at remote body sites unaffected by clinical pain. We further anticipated that pain sensitivity would differ as a function of the OA symptom severity. Older adults with and without symptomatic knee OA completed a series of experimental pain assessments. A median split of the Western Ontario and McMaster Universities Index of Osteoarthritis (WOMAC) was used to stratify participants into low vs. high OA symptom severity. Results Compared to controls and the low symptom group, individuals in the high symptom group were more sensitive to suprathreshold heat stimuli, blunt pressure, punctuate mechanical, and cold stimuli. Individuals in the low symptomatic OA group subgroup exhibited experimental pain responses similar to the pain-free group on most measures. No group differences in endogenous pain inhibition emerged. Conclusions These findings suggest that altered central processing of pain is particularly characteristic of individuals with moderate to severe symptomatic knee OA.

Assessment and manifestation of central sensitisation across different chronic pain conditions

“…However, one study did not show any differences (King et al, 2013b). Ethnic differences have been found in the facilitation of temporal summation in patients with OA and hence should be considered as a source of variation (Goodin et al, 2014).…”

“…Further, it has been found that the CPM is restored in patients after knee replacement where the patients became pain free (Kosek and Ordeberg, 2000;Graven-Nielsen et al, 2012). On the other hand, Finan et al (2013) found no difference in CPM potency between different OA sub-groups and King et al (2013b) found no differences between OA patients and controls.…”

“…For simple bedside testing, temporal summation evoked by repeated mechanical punctate pain stimuli has been used in OA (Cruz-Almeida et al, 2013;Finan et al, 2013;King et al, 2013b), and the summation has shown association with the pain severity but not the radiographic severity (Neogi et al, 2015). The subgroup of OA patients with 'high knee pain and low knee radiographic grade' showed more facilitated temporal summation to punctate pain stimuli than the other groups (Finan et al, 2013).…”

The Role of Preoperative Radiologic Severity, Sensory Testing, and Temporal Summation on Chronic Postoperative Pain Following Total Knee Arthroplasty

“…Similarly, Izumi et al, 2016 11 showed the same in severe hip OA patients compared with healthy controls. King et al, 2013 22 found that heat pain threshold and tolerance thresholds were elevated in patients with severe symptomatic KOA but not in patients with less symptomatic KOA compared with healthy controls. Further, studies have found heat related hypoesthesia and hypoalgesia in patients with lateral epicondylalgia 34 increased thermal detection thresholds, and skin biopsies confirmed a loss of small thin cutaneous never fibers.…”

“…Recently, thermal cutaneous hypoesthesia and hypoalgesia have been reported for knee OA pain 22,23 . A similar loss of function has been seen in patients with, e.g.…”