A randomized study comparing plasma concentration of ropivacaine after local infiltration analgesia and femoral block in primary total knee arthroplasty

Methods: Forty patients scheduled for primary total knee arthroplasty under spinal anaesthesia, were randomized to receive either local infiltration analgesia with a mixture of ropivacaine 300 mg, ketorolac 30mg and epinephrine or repeated femoral nerve block with ropivacaine in combination with three doses of 10mg intravenous ketorolac according to clinical routine. Plasma concentration of ropivacaine and ketorolac were quantified by liquid chromatography–mass spectrometry (LC–MS). Results: The maximal detected ropivacaine plasma level in the LIA group was not statistically higher than in the femoral block group using the Mann–Whitney U-test (p = 0.08). However, the median concentration in the LIA group was significantly higher than in the femoral block group (p < 0.0001; Mann–Whitney U-test). The maximal plasma concentrations of ketorolac following administration of 30mg according to the LIA protocol were detected 1 h or 2 h after release of the tourniquet in the LIA group: 152–958 ng/ml (95% CI: 303–512 ng/ml; n = 20). The range of the plasma concentration of ketorolac 2–3 h after injection of a single dose of 10mg was 57–1216 ng/ml (95% CI: 162–420 ng/ml; n = 20). Conclusion: During the first 24 h plasma concentration of ropivacaine seems to be lower after repeated femoral block than after LIA. Since the maximal ropivacaine level following LIA is detected around 4–6 h after release of the tourniquet, cardiac monitoring should cover this interval. Regarding ketorolac, our preliminary data indicate that the risk for concentration dependent side effects may be highest during the first hours after release of the tourniquet. Implication: Femoral block may be the preferred method for postoperative analgesia in patients with increased risk for cardiac side effects from ropivacaine. Administration of a booster dose of ketorolac shortly after termination of the surgical procedure if LIA was used may result in an increased risk for toxicity.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: A randomized study comparing plasma concentration of ropivacaine after local infiltration analgesia and femoral block in primary total knee arthroplasty ; volume:3 ; number:1 ; year:2012 ; pages:46-51 ; extent:6 ; Scandinavian journal of pain ; 3, Heft 1 (2012), 46-51 (gesamt 6)

Contributors, Places and Time

• Creator: Affas, Fatin ; Stiller, Carl-Olav ; Nygårds, Eva-Britt ; Stephanson, Niclas ; Wretenberg, Per ; Olofsson, Christina

Further information

• DOI: 10.1016/j.sjpain.2011.09.001
• URN: urn:nbn:de:101:1-2024022313582501817228
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 14.08.2025, 10:46 AM CEST