Joint inflammation is present in a subpopulation of knee osteoarthritis (OA) patients. Proinflammatory cytokines are known to sensitize the peripheral and central pain pathways. This can be mechanistically assessed by pressure pain thresholds and temporal summation of pain (TSP). Nonsteroidal anti-inflammatory drugs (NSAIDs) combined with paracetamol are recommended as OA treatment. The current study hypothesized that evidence of central sensitization would predict poor responses to peripherally directed therapies in knee OA and therefore aimed to investigate the value of mechanistic pain profiling for predicting pain outcome of treatment with NSAIDs plus paracetamol. One hundred thirty-two patients received ibuprofen 1200 mg/daily, paracetamol 3 g/daily, and pantoprazole 20 mg/daily for 3 weeks. Before administration, cuff pain detection, tolerance threshold, and TSP were assessed. Worst pain within the last 24 hours and pain during activity (visual analogue scales) were assessed before and after treatment. Facilitated TSP was found at baseline in the nonresponders to the 3-weeks treatment as compared to responders for both the 30% and 50% pain alleviation criteria (P < 0.02). Linear regression models identified facilitated TSP (P < 0.01) and low clinical pain scores (P < 0.001) as independent factors for prediction of poor pain alleviation by the treatment. In conclusion, this study found that mechanistic pain profiling can predict pain alleviation of NSAIDs and paracetamol. Facilitated TSP and low clinical pain scores before treatment are independent predictors of poor pain alleviation after NSAIDs and paracetamol. This study adds to the growing evidence that a subgroup of knee OA patients with manifested central sensitization may require special management attention.
This study found that facilitated temporal summation was associated with poor pain alleviation after 3-week treatment of nonsteroidal anti-inflammatory drugs and paracetamol.
aSMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
bCenter for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
cDepartment of Clinical Medicine, Aalborg University, Aalborg, Denmark
dMech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark
eDepartment of Orthopedic Surgery, Aalborg University Hospital, Aalborg, Denmark
Corresponding author. Address: SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7 D3, DK-9220 Aalborg, Denmark. Tel.: +45 9940 7529; fax: +45 9815 4008. E-mail address: KKP@HST.AAU.DK (K.K. Petersen).
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Received June 19, 2018
Received in revised form September 24, 2018
Accepted October 18, 2018