Objective: To determine whether neuropathic pain is a feature of first metatarsophalangeal (MTP) joint osteoarthritis (OA).
Methods: Ninety-eight participants (mean age 57.4 years, standard deviation 10.3) with symptomatic radiographic first MTP joint OA completed the painDETECT questionnaire (PDQ), which incorporates nine questions regarding the intensity and quality of pain. The likelihood of neuropathic pain was determined using established cut-points of the PDQ. Participants with unlikely neuropathic pain were then compared to those with possible/likely neuropathic pain in relation to age, sex, general health (Short Form [SF] 12), psychological wellbeing (Depression, Anxiety and Stress Scale), pain characteristics (self-efficacy, duration, and severity), foot health (Foot Health Status Questionnaire [FHSQ]), first MTP dorsiflexion range of motion and radiographic severity. Effect sizes (Cohen's d) were also calculated.
Results: Thirty (31%) participants had possible/likely neuropathic pain (possible n=19, [19.4%], likely n=11 [11.2%]). The most common neuropathic symptoms were sensitivity to pressure (56%), sudden pain attacks/electric shocks (36%) and burning (25%). Compared to those with unlikely neuropathic pain, those with possible/likely neuropathic pain were significantly older (d=0.59, p=0.010), had worse SF12 physical (d=1.10, p<0.001), pain self-efficacy (d=0.98, p<0.001), FHSQ pain (d=0.98, p<0.001) and FHSQ function (d=0.82, p<0.001) scores, and had higher pain severity at rest (d=1.01, p<0.001).
Conclusion: A significant proportion of individuals with first MTP joint OA report symptoms suggestive of neuropathic pain, which may partly explain the suboptimal responses to commonly used treatments for this condition. Screening for neuropathic pain may assist in the selection of targeted interventions and improve clinical outcomes.
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