Intra-Articular Morphine 5 mg After Knee Arthroscopy Does Not Produce Significant Pain Relief When Administered to Patients With Moderate to Severe Pain via an Intra-Articular Catheter

Intra-Articular Morphine for Inflammatory Pain

“…[6][7][8] This failure may be the result of a low number of functional opioid receptors at the peripheral sensory-nerve terminals, a relatively impermeable perineurial barrier, a low coupling efficacy of opioid receptors to G-proteins, or the absence of endogenous opioid ligands (reviewed in Stein et al 6 ). Thus, the present study confirms previous experience in that (1) analgesic effects are extremely difficult to detect when pain in the placebo group is low, and (2) patients without inflammatory pain are not the ideal population in which to demonstrate effects of peripherally applied opioids.…”

“…1 The IA application of opioids has been used for more than 15 years and is one of the most extensively investigated methods for pain management (more than 70 controlled trials published to date). However, some unresolved questions remain and continue to stimulate further investigations.…”

“…The authors find no significant differences in pain ratings between patients who received IA morphine or IA saline and no distinction between early and late removal of the catheter. 1 Two important points must be considered for adequate interpretation of this study: (1) As analyzed extensively in previous trials and reviews, to detect an analgesic effect, patients with sufficiently high baseline pain scores must be examined (ie, the study has to be "sensitive"). 2,3 In the present paper, the authors made an effort to assure sensitivity by assessing baseline pain within the first hour after patient emergence from general anesthesia, before IA compounds were injected.…”

Intra-Articular Morphine in Acute Pain Trials

“…1,2 In our study, we found no analgesic effect of 5 mg of IA morphine compared with placebo when given to patients with moderate or severe postoperative pain. Professor Stein disagrees with our interpretation.…”

Single-Dose Intra-Articular Bupivacaine Versus Morphine After Arthroscopic Knee Surgery

“…[3][4][5] Morphine is a potent opiate analgesic drug that is commonly used to relieve pain. [6][7][8] Apart from the IA morphine, bupivacaine is one of the most often stated analgesics that could effectively reduce pain in the earliest period after arthroscopic knee surgery. [9][10][11][12] A majority of existing studies have suggested that IA morphine provides better postoperative pain relief than IA bupivacaine and have supported its use after arthroscopy.…”