title: Comparison of postoperative pain in the first and second knee in staged bilateral total knee arthroplasty: clinical evidence of enhanced pain sensitivity after surgical injury.
abstract: Staged bilateral total knee arthroplasty (TKA) may provide an ideal clinical model for the study of central sensitization. In staged TKA, hyperalgesia may be induced as a result of repeated surgical injury possibly via central sensitization, which can decrease functional outcomes. Therefore, we hypothesized that in staged bilateral TKA, patients would have greater pain in the second operated knee than in the first. Thirty patients undergoing staged bilateral TKA at a 1-week interval were enrolled. Postoperative pain, which was reported on the basis of a visual analog scale (VAS; primary outcome) at rest and at maximum knee flexion, and the amount of patient-controlled analgesic (i.v. fentanyl) and rescue analgesic (i.v. ketoprofen; secondary outcomes) administered during the 48 h after the operation, were compared between the first and second TKA. VAS scores at rest and at maximum knee flexion were greater on the second operated knee (P<.001 and P<.01, respectively). The cumulative amounts of patient-controlled analgesic and the rescue analgesic were greater in the second than in the first TKA (P<.001 and P<.05, respectively). Patients undergoing staged bilateral TKA experience greater postoperative pain in the second operated knee than the first. This suggests extension of hyperalgesia beyond the initially injured site to remote regions after surgical injury, in which central sensitization may be involved. Therapeutic approaches to reduce such hyperalgesia induced in the course of staged operations are required.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Seongnam-si, Gyeonggi-do, South Korea Joint Reconstruction Center, Department of Orthopedic Surgery, Seoul National University Bundang Hospital, 166, Gumi-ro, Seongnam-si, Gyeonggi-do, South Korea.
authors.forename: Mi-Hyun
authors.initials: MH
authors.lastname: Kim
authors.forename: Francis Sahngun
authors.initials: FS
authors.lastname: Nahm
authors.forename: Tae Kyun
authors.initials: TK
authors.lastname: Kim
authors.forename: Moon Jong
authors.initials: MJ
authors.lastname: Chang
authors.forename: Sang-Hwan
authors.initials: SH
authors.lastname: Do
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000503:physiopathology* / Q000628:therapy; D007717:Knee / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D010149:Postoperative Pain / Q000209:etiology*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D013997:Time Factors
keywords: Arthroplasty, replacement, knee; Central nervous system sensitization; Hyperalgesia; Pain, postoperative