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Chronic postoperative pain after total knee arthroplasty: The potential contributions of synovitis, pain sensitization and pain catastrophizing—An explorative study


Thomas Kurien

Robert W. Kerslake

Thomas Graven?Nielsen

Lars Arendt?Nielsen

Professor of Sport, exercise and Nutrition Education

Brigitte E. Scammell



Background: A subset of osteoarthritis patients will experience chronic postoperative pain after total knee arthroplasty (TKA), but the source of pain is unclear. The aim of this exploratory study was to assess patients with and without postoperative pain after TKA using magnetic resonance imaging (MRI), quantitative sensory testing (QST), clinical assessment of pain and assessments of catastrophizing thoughts. Methods: Forty-six patients completed the 6-month postoperative assessment. MRI findings were scored according to the MRI Osteoarthritis Knee Score recommendation for Hoffa synovitis, effusion size and bone marrow lesions. QST included assessment of pressure pain thresholds (PPTs), temporal summation of pain (TSP) and conditioned pain modulation (CPM). Pain catastrophizing was assessed using the Pain Catastrophizing Scale (PCS). Clinical pain assessment was conducted using a visual analogue scale (VAS, 0–10cm), and groups of moderate-to-severe (VAS > 3) and none-to-mild postoperative pain (VAS ≤ 3) were identified. Results: Patients with moderate-to-severe postoperative pain (N= 15) demonstrated higher grades of Hoffa synovitis (p< 0.001) and effusion size (p< 0.001), lower PPTs (p= 0.039), higher TSP (p= 0.001) and lower CPM (p= 0.014) when compared with patients with none-to-mild postoperative pain (N= 31). No significant difference was found in PCS scores between the two groups. Multiple linear regression models found synovitis (p= 0.036), effusion size (p= 0.003), TSP (p= 0.013) and PCS (p< 0.001) as independent parameters contributing to the postoperative pain intensity. Conclusion: These exploratory findings could indicate that chronic postoperative pain after TKA is a combination of joint-related synovitis and effusion, sensitization of central pain mechanisms and potentially pain catastrophizing thoughts, but larger studies are needed to confirm this. Significance: The end-stage treatment of knee osteoarthritis is total knee arthroplasty. Some patients experience chronic postoperative pain after total knee arthroplasty, but the mechanism for chronic postoperative pain is widely unknown. The current study indicates that higher levels postoperative of synovitis and effusion, higher temporal summation of pain and higher pain catastrophizing scores could be associated with higher chronic postoperative pain.


Kurien, T., Kerslake, R. W., Graven‐Nielsen, T., Arendt‐Nielsen, L., Auer, D. P., Edwards, K., …Petersen, K. K. (2022). Chronic postoperative pain after total knee arthroplasty: The potential contributions of synovitis, pain sensitization and pain catastrophizing—An explorative study. European Journal of Pain, 26(9), 1979-1989.

Journal Article Type Article
Acceptance Date Aug 7, 2022
Online Publication Date Aug 19, 2022
Publication Date 2022-10
Deposit Date Sep 12, 2022
Publicly Available Date Sep 12, 2022
Journal European Journal of Pain
Print ISSN 1090-3801
Electronic ISSN 1532-2149
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 26
Issue 9
Pages 1979-1989
Keywords Anesthesiology and Pain Medicine
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