Osteoarthritis (OA) is traditionally considered a progressive disorder of articular cartilage in the joint, yet increasing evidence suggests that at least in an important subgroup of patients with OA the clinical picture is dominated by sensitization of central nervous system pain pathways (i.e. central sensitization) rather than by structural dysfunctions causing nociceptive pain (reviewed by Lluch et al. 2013). A systematic literature review considered evidence for the presence of sensitization in people with OA of the hip, knee, first carpometacarpal joint and lower limb, and reported that the majority of the literature suggests that the central nervous system becomes hypersensitized in people with OA pain (Lluch et al. 2014).
To advance and expand upon the work of this previous review, the aim of the current study was to conduct a meta-analytic review of the evidence for pain sensitization as measured by Quantitative Sensory Testing (QST) specifically in people with knee OA. Evidence from this systematic review and meta-analysis suggests that pain sensitization is present in people with knee OA and may be associated with knee OA symptom severity. However, the mechanisms by which sensitization may occur in people with knee OA are still unclear. Future research is needed to identify people with knee OA in whom sensitization is a dominant feature; to establish predictors of ongoing sensitization after a total knee replacement and to assess the response of sensitized knee OA groups to commonly used conservative treatments.
Isabel Baert
2015 Pain in Motion