Moderate-to-severe pain after knee arthroscopy is relieved by intraarticular saline: a randomized controlled trial

Anesth Analg. 2004 Jun;98(6):1546-51, table of contents. doi: 10.1213/01.ane.0000112433.71197.fa.

Abstract

We have previously studied intraarticular (IA) analgesics compared with saline 10 mL in 2 randomized clinical trials. The patients who were given IA saline experienced rapid pain relief. Hypothetically, saline may produce a local analgesic effect by cooling or by diluting IA algogenic substances. This randomized double-blind study compared the analgesic effect of IA saline 10 mL with saline 1 mL, which should be a pure placebo. A soft catheter was left IA in 79 patients. We included 60 patients who developed moderate-to-severe pain within 1 h after knee arthroscopy under general anesthesia. A randomized, double-blind controlled comparison of IA saline 10 mL with saline 1 mL followed. Outcome measures were pain intensity, pain relief, and analgesic consumption. Within 1 h pain intensity decreased in both groups from approximately 50 to approximately 27 on a 0-100 mm visual analog scale. Pain intensity remained low and other pain outcome measures were similar during the 36-h observation period. The patients experienced equally good pain relief after IA injection of saline 10 mL and 1 mL. Our finding of a major placebo effect may have implications for the interpretation of previously published placebo-controlled IA analgesia studies.

Implications: In a randomized controlled trial we showed that pain after knee arthroscopy is modest and short-lived and can successfully be treated with intraarticular saline as placebo.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Arthroscopy / adverse effects*
  • Chi-Square Distribution
  • Double-Blind Method
  • Female
  • Humans
  • Injections, Intra-Articular
  • Knee Joint / drug effects*
  • Knee Joint / surgery
  • Male
  • Middle Aged
  • Pain / drug therapy*
  • Pain Measurement / drug effects
  • Pain Measurement / methods
  • Sodium Chloride / administration & dosage*

Substances

  • Sodium Chloride