title: Widespread sensitization in patients with chronic pain after revision total knee arthroplasty.
abstract: Pain and sensitization are major issues in patients with osteoarthritis both before and after total knee arthroplasty (TKA) and revision TKA (re-TKA). The aim of this study was to assess sensitization in patients with and without chronic pain after re-TKAs. Twenty patients with chronic knee pain and 20 patients without pain after re-TKA participated. Spreading of pain was evaluated as the number of pain sites using a region-divided body chart. The pressure pain threshold (PPT) and pressure pain tolerance (PTT) were assessed by cuff algometry at the lower leg. Temporal summation of pain was assessed by recordings of the pain intensity on a visual analog scale (VAS) during repeated cuff pressure stimulations. Conditioning pain modulation (CPM) was recorded by experimental tonic arm pain by cuff pressure stimulation and assessment of PPTs on the knee, leg, and forearm using handheld pressure algometry. Participants with pain after re-TKA compared to participants without pain demonstrated: (1) significantly more pain sites (P=.004), (2) decreased cuff PPTs and PTTs at the lower leg (P<.001), (3) facilitated temporal summation (P<.001), and (4) impaired CPM (P<.001). Additionally, significant correlations between knee pain intensity and cuff PPTs, temporal summation, and CPM and between total duration of knee pain and temporal summation were found (P<.05). This study demonstrated widespread sensitization in patients with pain after re-TKA and highlighted the importance of ongoing nociceptive input for the chronification process. This has important implications for future revisions, and precautions should be taken if patients have widespread sensitization.
authors.affiliation: Orthopaedic Surgery Research Unit, Aalborg University Hospital, Aalborg, Denmark Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Soren Thorgaard
authors.initials: ST
authors.lastname: Skou
authors.forename: Thomas
authors.initials: T
authors.lastname: Graven-Nielsen
authors.forename: Sten
authors.initials: S
authors.lastname: Rasmussen
authors.forename: Ole H
authors.initials: OH
authors.lastname: Simonsen
authors.forename: Mogens B
authors.initials: MB
authors.lastname: Laursen
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001132:Arm / Q000294:innervation; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D059350:Chronic Pain / Q000209:etiology / Q000523:psychology* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D011312:Pressure; D013223:Statistics as Topic; D011795:Surveys and Questionnaires
keywords: Cuff algometry; Experimental pain; Knee osteoarthritis; Pain mechanisms; Pressure algometry; Reoperation; Spreading of pain; Spreading sensitization