Antiinflammatory effect of peripheral nerve blocks after knee surgery: clinical and biologic evaluation.
BACKGROUND
Nerve blocks provide analgesia after surgery. The authors tested whether nerve blocks have antiinflammatory effects.


METHODS
Patients had combined sciatic (single-shot) and continuous femoral block (48 h) (block group) or morphine patient-controlled analgesia after total knee arthroplasty. Pain at rest and upon movement was monitored at 1 (D1), 4 (D4), and 7 days (D7) and 1 (M1) and 3 months (M3) after surgery. Knee inflammation was evaluated (skin temperature, knee circumference) before surgery and at D1, D4, D7, M1, and M3. Plasma cytokine concentrations (interleukin [IL]-6, IL-1beta, tumor necrosis factor [TNF], IL-10, soluble receptor 1 of TNF [sTNF-R1]) were measured before surgery and at 4 h, D1, D4, and D7 after surgery. Capsule and synovial membrane cytokines were measured (IL-6, TNF, IL-1, IL-10). Knee flexion was evaluated before surgery and at D1, D4, D7, M1, and M3. Morphine use and recovery time to autonomy were monitored.


RESULTS
Pain at rest and upon movement was lower in the block group than in patient-controlled analgesia patients between D1 and D7 (analysis of variance, P < 0.005). Knee flexion was improved in the block group for D1 to M1 (analysis of variance, P < 0.0001). Block group patients recovered nonassisted mobilization (t test, P = 0.04) and toilet use (t test, P = 0.03) more rapidly. Knee circumference and skin temperature were lower in the block group between D1 and D7 (analysis of variance, P < 0.05). Synovial membrane IL-1 (P < 0.05) and IL-10 (P < 0.01) increased, and plasma IL-6 and sTNF-R1 peaked at 24 h, with no difference between groups.


CONCLUSIONS
Nerve blocks inhibited clinical inflammation after total knee arthroplasty, with no change in tissue and plasma cytokine concentrations.
Martin
Frédéric
F
Service d'anesthésie, Assistance Publique Hôpitaux de Paris, Hôpital Raymond Poincaré, Garches, France.
Martinez
Valéria
V
Mazoit
Jean Xavier
JX
Bouhassira
Didier
D
Cherif
Kamel
K
Gentili
Marc Edouard
ME
Piriou
Philippe
P
Chauvin
Marcel
M
Fletcher
Dominique
D
D000368:Aged; D000577:Amides / Q000008:administration & dosage / Q000627:therapeutic use*; D016058:Analgesia, Patient-Controlled; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D016207:Cytokines / Q000097:blood / Q000378:metabolism; D005260:Female; D005267:Femoral Nerve / Q000187:drug effects; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D009020:Morphine / Q000008:administration & dosage; D009407:Nerve Block / Q000379:methods*; D010147:Pain Measurement / Q000706:statistics & numerical data; D010149:Postoperative Pain / Q000188:drug therapy*; D010525:Peripheral Nerves / Q000187:drug effects* / Q000276:immunology; D016059:Range of Motion, Articular / Q000187:drug effects; D000077212:Ropivacaine; D012584:Sciatic Nerve / Q000187:drug effects
D000577:Amides; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D000893:Anti-Inflammatory Agents; D016207:Cytokines; D009020:Morphine; D000077212:Ropivacaine