A Systematic Review of the Efficacy and Safety of Ketamine in Total Joint Arthroplasty

N-Methyl-D-aspartate receptor antagonists for the prevention of chronic postsurgical pain: a narrative review

The N-methyl-D-aspartate receptor (NMDAR) has been linked to the development of chronic postsurgical pain (CPSP), defined as pain after surgery that does not resolve by 3 months. Once the combination of a painful stimulus and glutamate binding activates the NMDAR, calcium influx triggers signaling cascades that lead to processes like central sensitization and CPSP. Three of the most widely studied perioperative NMDAR antagonists include ketamine, magnesium, and methadone, with ketamine having garnered the greatest amount of attention. While multiple studies have found improved analgesia in the acute postoperative period, fewer studies have focused on long-term outcomes and those that have are often underpowered for CPSP or have not included those patients at highest risk. Existing meta-analyses of ketamine for CPSP are inconsistent in their findings, and studies of magnesium and methadone are even more limited. Overall, the evidence supporting NMDAR antagonists for CPSP is weak and we recommend that future studies focus on high-risk patients and potentially include combinations of NMDAR antagonists administered together for the longest duration feasible. The results of ongoing trials could have a major influence on the overall direction of the evidence supporting NMDAR antagonists in preventing CPSP.

The Impact of Ketamine on Outcomes in Acute Pain Management: An Umbrella Review

Background/Objectives: Ketamine offers effective pain relief with fewer side effects than traditional analgesics, making it a promising alternative for acute pain treatment. However, further research is needed to fully assess its role in perioperative care. This umbrella review aimed to compile the highest-quality evidence available regarding the application of ketamine in managing acute pain. Methods: A thorough search of the literature was carried out in PubMed, Scopus, and the Cochrane Library, including systematic reviews that focused on the application of ketamine in managing acute pain. The data extraction included the research type, analgesics used, number of studies and patients per review, pain types, scoring methods, ketamine doses, administration routes, and reporting guidelines. Results: Of the 807 records identified, 20 studies met the inclusion criteria. In accordance with the AMSTAR-2 evaluation, most of the systematic reviews were rated as critically low quality. Intravenous ketamine administered during the perioperative period was found to reduce the pain intensity of acute pain within 15-30 and 60 min following treatment, and decrease postoperative opioid consumption by 14-50% at both 24 and 48 h after surgery. Conclusions: Evidence shows that intravenous ketamine reduces the pain intensity, postoperative opioid use, and the risk of vomiting and nausea while improving analgesia, making it a valuable adjunct in perioperative pain management.

Use of Ketamine in Patients with Multifactorial Neuropathic Pain: A Systematic Review and Meta-Analysis

Neuropathic pain (NP) is a heterogeneous group of conditions characterized by the experience of a number of sensory disturbances including pain, burning sensations, paroxysms of stabbing pain, dysesthesias, allodynia, and hyperalgesia. The above-mentioned sensations may occur in a specific dermatome area or other delimited region of the body. The objective of this review was to analyze the evidence for ketamine in multifactorial neuropathic pain. The research group systematically searched the databases MEDLINE (via PubMed), EMBASE, SCOPUS, the Cochrane Central Register of Controlled Trials, the Cumulative Index to Nursing and Allied Health Literature (Cinahl), and the Web of Science. The findings of this review show that different forms of low doses of ketamine (LDK) do not present statistically significant changes for any of the scales included. In this study, the total symptom score [standardized mean difference (SMD) = -3.59, confidence interval (CI) = -4.16 to -3.02, and p < 0.00001], neuropathy impairment score (SMD = -1.42, CI = -3.68 to 0.84, and p = 0.22), and neuropathy symptom checklist (SMD = -0.09, CI = -0.15 to -0.02, and p = 0.01) were taken into account. For finality compared to the use of a placebo, the findings suggest that LDK does not exhibit significant differences in terms of pain reduction and functionality. Moreover, no specific dosages are identified to support the use of LDK in the reduction in NP.

Osteoporosis, Osteoarthritis, and Subchondral Insufficiency Fracture: Recent Insights

The increased incidence of osteoarthritis (OA), particularly knee and hip OA, and osteoporosis (OP), owing to population aging, have escalated the medical expense burden. Osteoarthritis is more prevalent in older women, and the involvement of subchondral bone fragility spotlights its association with OP. Notably, subchondral insufficiency fracture (SIF) may represent a more pronounced condition of OA pathophysiology. This review summarizes the relationship between OA and OP, incorporating recent insights into SIF. Progressive SIF leads to joint collapse and secondary OA and is associated with OP. Furthermore, the thinning and fragility of subchondral bone in early-stage OA suggest that SIF may be a subtype of OA (osteoporosis-related OA, OPOA) characterized by significant subchondral bone damage. The high bone mineral density observed in OA may be overestimated due to osteophytes and sclerosis and can potentially contribute to OPOA. The incidence of OPOA is expected to increase along with population aging. Therefore, prioritizing OP screening, early interventions for patients with early-stage OA, and fracture prevention measures such as rehabilitation, fracture liaison services, nutritional management, and medication guidance are essential.

Evaluating the effects of S-ketamine on postoperative delirium in elderly patients following total hip or knee arthroplasty under intraspinal anesthesia: a single-center randomized, double-blind, placebo-controlled, pragmatic study protocol

Introduction

Postoperative delirium (POD) is an acute, transient brain disorder associated with decreased postoperative quality of life, dementia, neurocognitive changes, and mortality. A small number of trials have explored the role of S-ketamine in the treatment of POD due to its neuroprotective effects. Surprisingly, these trials have failed to yield supportive results. However, heterogeneity in delirium assessment methodologies, sample sizes, and outcome settings as well as deficiencies in S-ketamine use methods make the evidence provided by these studies less persuasive. Given the severe impact of POD on the health of elderly patients and the potential for S-ketamine to prevent it, we believe that designing a large sample size, and rigorous randomized controlled trial for further evaluation is necessary.

Methods

This is a single-center, randomized, double-blind, placebo-controlled, pragmatic study. Subjects undergoing total hip or knee arthroplasty will be randomized in a 1:1 ratio to intervention (n = 186) and placebo (n = 186) groups. This trial aims to explore the potential role of S-ketamine in the prevention of POD. Its primary outcome is the incidence of POD within 3 postoperative days. Secondary outcomes include the number of POD episodes, the onset and duration of POD, the severity and subtype of POD, pain scores and opioid consumption, sleep quality, clinical outcomes, and safety outcomes.

Discussion

To our knowledge, this is the first pragmatic study that proposes to use S-ketamine to prevent POD. We reviewed a large body of literature to identify potential preoperative confounding variables that may bias associations between the intervention and primary outcome. We will use advanced statistical methods to correct potential confounding variables, improving the test's power and external validity of test results. Of note, the patient population included in this trial will undergo intraspinal anesthesia. Although large, multicenter, randomized controlled studies have found no considerable difference in the effects of regional and general anesthesia on POD, patients receiving intraspinal anesthesia have less exposure to at-risk drugs, such as sevoflurane, propofol, and benzodiazepines, than patients receiving general anesthesia. At-risk drugs have been shown to negatively interfere with the neuroprotective effects of S-ketamine, which may be the reason for the failure of a large number of previous studies. There is currently a lack of randomized controlled studies evaluating S-ketamine for POD prevention, and our trial helps to fill a gap in this area.Trial registration: http://www.chictr.org.cn, identifier ChiCTR2300075796.