Perioperative medicine training resources: U5M10: Role, protocols and management of analgesics

Abstract
Cannabis use is increasingly prevalent. Cannabinoid receptors regulate pro-inflammatory cytokines, and compounds in marijuana exert diverse physiologic effects. As more patients use cannabis, clinicians should recognize implications of perioperative cannabis use. Although the role of cannabis use in perioperative pain control has been explored, little is known about its effect on perioperative wound healing or on hematologic, pulmonary, and cardiovascular physiology.

Methods: We searched PubMed for English-language articles related to cannabis (ie, marijuana, cannabidiol oil, and tetrahydrocannabinol) and wound healing, cardiovascular, pulmonary, or hematologic outcomes, and surgery. Titles and abstracts were reviewed, and relevant articles were analyzed. Human, animal, and pathology studies were included. Editorials, case reports, and review articles were excluded.

Results: In total, 2549 wound healing articles were identified; 5 human studies and 8 animal/pathology studies were included. Results were conflicting. An estimated 2900 articles related to cardiovascular effects were identified, of which 2 human studies were included, which showed tetrahydrocannabinol and marijuana caused tachycardia. A total of 142 studies regarding pulmonary effects were identified. Three human studies were included, which found no difference in respiratory complications. In total, 114 studies regarding hematologic effects were identified. The 3 included human studies found conflicting venous thromboembolism risks. The overall study quality was poor. Information about dose/duration, administration route, and follow-up was reported with variable completeness.

Conclusions: Surgeons should consider effects of cannabis in the perioperative setting. Little is known about its perioperative effects on wound healing, or on cardiovascular, pulmonary, and hematologic physiology. Further research should elucidate the effects of administration route, dose, and timing of cannabis use among surgical patients.

Abstract
Purpose: The aim of the study was to assess whether administration of a single dose of methylprednisolone in the group patients above 65 years of age will be effective in complex analgesic management after total hip arthroplasty (THA).

Methods: Seventy-seven patients above 65 years old were double-blind randomized into two: the study and controls groups. Pre-operatively, the study group received as a single dose of 125 mg intravenous methylprednisolone, while the others saline solution as placebo. Peri-operatively, all the patients were administered opioid and nonopioid analgesic agents. We measured the levels of inflammatory markers (leukocytosis, C-reactive protein-CRP), pain intensity level (visual analog scale-VAS; numerical rating scale-NRS), the life parameters, and noted complications.

Results: Following administration of methylprednisolone were significantly lower levels of CRP on all the four post-operative days; leukocytosis on the second day; the VAS/NRS score at rest after six, 12, and 18 hours post-operatively, diminished the dose of parenteral opioid preparations (oxycodone hydrochloride), the duration of analgesia by peripheral nerve block was significantly higher as compared with the placebo group (p < 0.000001). No infectious complications were noted; there was one patient who developed post-operative delirium.

Conclusion: A single dose of methylprednisolone significantly reduces the level of post-operative pain at rest on the day of THA in the group patients above 65 years of age, decreases the dose of opioid analgesic agents, and significantly decreases the level of inflammatory markers, without infectious processes.

Abstract
Total hip and knee arthroplasty is associated with significant perioperative pain, which can adversely affect recovery by increasing risk of complications, length of stay, and cost. Historically, opioids were the mainstay of perioperative pain control. However, opioids are associated with significant downsides. Preemptive use of a multimodal pain management approach has become the standard of care to manage pain after hip and knee arthroplasty. Multimodal pain management uses oral medicines, peripheral nerve blocks, intra-articular injections, and other tools to reduce the need for opioids. Use of a multimodal approach promises to decrease complications, improve outcomes, and increase patient satisfaction after hip and knee arthroplasty.

Abstract
Studies have identified demographic, clinical, psychosocial, and perioperative variables associated with persistent pain after a variety of surgeries. This study aimed to perform a systematic review and meta-analysis of factors associated with persistent pain after total knee replacement (TKR) and total hip replacement (THR) surgeries. To meet the inclusion criteria, studies were required to assess variables before or at the time of surgery, include a persistent postsurgical pain (PPSP) outcome measure at least 2 months after a TKR or THR surgery, and include a statistical analysis of the effect of the risk factor(s) on the outcome measure. Outcomes from studies implementing univariate and multivariable statistical models were analyzed separately. Where possible, data from univariate analyses on the same factors were combined in a meta-analysis. Eighty-one studies involving 171,354 patients were included in the review. Because of the heterogeneity of assessment methods, only 44% of the studies allowed meaningful meta-analysis. In meta-analyses, state anxiety (but not trait anxiety) scores and higher depression scores on the Beck Depression Inventory were associated with an increased risk of PPSP after TKR. In the qualitative summary of multivariable analyses, higher preoperative pain scores were associated with PPSP after TKR or THR. This review systematically assessed factors associated with an increased risk of PPSP after TKR and THR and highlights current knowledge gaps that can be addressed by future research.

Abstract
Objectives: Guideline adherence for hip and knee osteoarthritis management is often poor, possibly related to the quality and/or inconsistent recommendations. This systematic review of hip and knee osteoarthritis guidelines aimed to appraise the quality and consistency in recommendations across higher-quality guidelines.

Methods: Eight databases, guideline repositories, and professional associations websites were searched on 27/10/2022. Guideline quality was appraised using the Appraisal of Guidelines for Research and Evaluation II (AGREE II tool) (six domains). Higher quality was defined as scoring ≥60% for domains 3 (rigour of development), 6 (editorial independence), plus one other. Consistency in recommendations across higher-quality guidelines was reported descriptively. This review was registered prospectively (CRD42021216154).

Results: Seven higher-quality and 18 lesser-quality guidelines were included. AGREE II domain scores for higher-quality guidelines were > 60% except for applicability (average 46%). Higher-quality guidelines consistently recommended in favour of education, exercise, and weight management and non-steroidal anti-inflammatory drugs (hip and knee), and intra-articular corticosteroid injections (knee). Higher quality guidelines consistently recommended against hyaluronic acid (hip) and stem cell (hip and knee) injections. Other pharmacological recommendations in higher-quality guidelines (e.g., paracetamol, intra-articular corticosteroid (hip), hyaluronic acid (knee)) and adjunctive treatments (e.g., acupuncture) were less consistent. Arthroscopy was consistently recommended against in higher-quality guidelines. No higher-quality guidelines considered arthroplasty.

Conclusion: Higher-quality guidelines for hip and knee osteoarthritis consistently recommend clinicians implement exercise, education, and weight management, alongside consideration of Non-Steroidal Anti-Inflammatory Drugs and intra-articular corticosteroid injections (knee). Lack of consensus on some pharmacological options and adjunctive treatments creates challenges for guideline adherence. Future guidelines must prioritise providing implementation guidance, considering consistently low applicability scores.

Abstract
Objective: To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

Methods: We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

Results: The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

Conclusion: This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

Abstract
Surgical procedures are key drivers of pain development and opioid utilization globally. Various organizations have generated guidance on postoperative pain management, enhanced recovery strategies, multimodal analgesic and anesthetic techniques, and postoperative opioid prescribing. Still, comprehensive integration of these recommendations into standard practice at the institutional level remains elusive, and persistent postoperative pain and opioid use pose significant societal burdens. The multitude of guidance publications, many different healthcare providers involved in executing them, evolution of surgical technique, and complexities of perioperative care transitions all represent challenges to process improvement. This review seeks to summarize and integrate key recommendations into a "roadmap" for institutional adoption of perioperative analgesic and opioid optimization strategies. We present a brief review of applicable statistics and definitions as impetus for prioritizing both analgesia and opioid exposure in surgical quality improvement. We then review recommended modalities at each phase of perioperative care. We showcase the value of interprofessional collaboration in implementing and sustaining perioperative performance measures related to pain management and analgesic exposure, including those from the patient perspective. Surgery centers across the globe should adopt an integrated, collaborative approach to the twin goals of optimal pain management and opioid stewardship across the care continuum.

Keywords: Evidence-based medicine; Multimodal analgesia; Perioperative pain; Regional analgesia; Regional anesthesia.

Abstract
Background: Although pain is common in osteoarthritis, most people fail to achieve adequate analgesia. Increasing acknowledgement of the contribution of pain sensitisation has resulted in the investigation of medications affecting pain processing with central effects. Antidepressants contribute to pain management in other conditions where pain sensitisation is present.

Objectives: To assess the benefits and harms of antidepressants for the treatment of symptomatic knee and hip osteoarthritis in adults.

Search methods: We used standard, extensive Cochrane search methods. The latest search was January 2021.

Selection criteria: We included randomised controlled trials of adults with osteoarthritis that compared use of antidepressants to placebo or alternative comparator. We included trials that focused on efficacy (pain and function), treatment-related adverse effects and had documentation regarding discontinuation of participants. We excluded trials of less than six weeks of duration or had participants with concurrent mental health disorders.

Data collection and analysis: We used standard Cochrane methods. Major outcomes were pain; responder rate; physical function; quality of life; and proportion of participants who withdrew due to adverse events, experienced any adverse events or had serious adverse events. Minor outcomes were proportion meeting the OARSI (Osteoarthritis Research Society International) Response Criteria, radiographic joint structure changes and proportion of participants who dropped out of the study for any reason. We used GRADE to assess certainty of evidence.

Main results: Nine trials (2122 participants) met the inclusion criteria. Seven trials examined only knee osteoarthritis. Two also included participants with hip osteoarthritis. All trials compared antidepressants to placebo, with or without non-steroidal anti-inflammatory drugs. Trial sizes were 36 to 388 participants. Most participants were female, with mean ages of 54.5 to 65.9 years. Trial durations were 8 to 16 weeks. Six trials examined duloxetine. We combined data from nine trials in meta-analyses for knee and hip osteoarthritis. One trial was at low risk of bias in all domains. Five trials were at risk of attrition and reporting bias. High-certainty evidence found that antidepressants resulted in a clinically unimportant improvement in pain compared to placebo. Mean reduction in pain (0 to 10 scale, 0 = no pain) was 1.7 points with placebo and 2.3 points with antidepressants (mean difference (MD) -0.59, 95% confidence interval (CI) -0.88 to -0.31; 9 trials, 2122 participants). Clinical response was defined as achieving a 50% or greater reduction in 24-hour mean pain. High-certainty evidence demonstrated that 45% of participants receiving antidepressants had a clinical response compared to 28.6% receiving placebo (RR 1.55, 95% CI 1.32 to 1.82; 6 RCTs, 1904 participants). This corresponded to an absolute improvement in pain of 16% more responders with antidepressants (8.9% more to 26% more) and a number needed to treat for an additional beneficial effect (NNTB) of 6 (95% CI 4 to 11). High-certainty evidence showed that the mean improvement in function (on 0 to 100 Western Ontario and McMaster Universities Arthritis Index, 0 = best function) was 10.51 points with placebo and 16.16 points with antidepressants (MD -5.65 points, 95% CI -7.08 to -4.23; 6 RCTs, 1909 participants). This demonstrates a small, clinically unimportant response. Moderate-certainty evidence (downgraded for imprecision) showed that quality of life measured using the EuroQol 5-Dimension scale (-0.11 to 1.0, 1.0 = perfect health) improved by 0.07 points with placebo and 0.11 points with antidepressants (MD 0.04, 95% CI 0.01 to 0.07; 3 RCTs, 815 participants). This is clinically unimportant. High-certainty evidence showed that total adverse events increased in the antidepressant group (64%) compared to the placebo group (49%) (RR 1.27, 95% CI 1.15 to 1.41; 9 RCTs, 2102 participants). The number needed to treat for an additional harmful outcome (NNTH) was 7 (95% CI 5 to 11). Low-certainty evidence (downgraded twice for imprecision for very low numbers of events) found no evidence of a difference in serious adverse events between groups (RR 0.94, 95% CI 0.46 to 1.94; 9 RCTs, 2101 participants). The NNTH was 1000. Moderate-certainty evidence (downgraded for imprecision) showed that 11% of participants receiving antidepressants withdrew from trials due to an adverse event compared to 5% receiving placebo (RR 2.15, 95% CI 1.56 to 2.97; 6 RCTs, 1977 participants). The NNTH was 17 (95% CI 10 to 35).

Authors' conclusions: There is high-certainty evidence that use of antidepressants for knee osteoarthritis leads to a non-clinically important improvement in mean pain and function. However, a small number of people will have a 50% or greater important improvement in pain and function. This finding was consistent across all trials. Pain in osteoarthritis may be due to a variety of causes that differ between individuals. It may be that the cause of pain that responds to this therapy is only present in a small number of people. There is moderate-certainty evidence that antidepressants have a small positive effect on quality of life with heterogeneity between trials. High-certainty evidence indicates antidepressants result in more adverse events and moderate-certainty evidence indicates more withdrawal due to adverse events. There was little to no difference in serious adverse events (low-certainty evidence due to low numbers of events). This suggests that if antidepressants were being considered, there needs to be careful patient selection to optimise clinical benefit given the known propensity for adverse events with antidepressant use. Future trials should include alternative antidepressant agents or phenotyping of pain in people with osteoarthritis, or both.

Abstract
Study objective: Post-surgical chronic pain with a neuropathic component is usually more severe and leads to worse quality of life. We conducted this systematic review to examine the evidence of topical lidocaine for post-surgical neuropathic pain.

Design: Systematic review with meta-analysis.

Setting: Published randomized controlled trials (RCTs) comparing topical lidocaine with placebo or no topical lidocaine for post-surgical neuropathic pain.

Patients: Seven RCTs including 585 patients.

Interventions: We systematically searched databases for randomized controlled trials (RCTs) investigating the effect and safety outcomes of topical lidocaine compared with placebo or no intervention.

Measurements: We conducted meta-analyses to evaluate the effect of topical lidocaine on pain intensity, adverse events, and quality of life. Standardized mean difference (SMD) and relative risk (RR) with 95% CIs were effect measures for continuous and dichotomous outcomes, respectively. We assessed the risk of bias of included trials and the certainty of evidence for each outcome.

Main results: Our review included 7 studies with 585 participants. There is moderate certainty evidence that topical lidocaine may increase the likelihood of global pain relief, with a relative risk (RR) of 1.98 (95% confidence interval (CI): 1.04, 3.76; I2 = 70%, P = 0.04). Low certainty evidence suggested topical lidocaine may lead to more reduction in pain intensity (SMD: -0.70; 95% confidence interval: -1.46, 0.06; I2 = 93%, P = 0.07). High certainty evidence showed that topical lidocaine did not increase the adverse event risk (RR: 1.04; 95% CI: 0.93, 1.16; I2 = 0%, P = 0.51).

Conclusions: Topical lidocaine may lead to pain relief and is safe to use for patient with post-surgical pain, though its impact on quality of life is unclear. This review supports the use of topical lidocaine for patients with post-surgical pain, and reveals the evidence gap in topical lidocaine use. (Registration: PROSPERO CRD42021294100).

Abstract
The aging population and the obesity epidemic have led to an increased rate of joint arthroplasty procedures, specifically total knee arthroplasty and total hip arthroplasty. These surgeries are associated with increased hospital length of stay and, consequently, higher costs. Despite the benefits of outpatient surgery, only a small percentage of total joint arthroplasties (TJAs) are done in this manner. We reviewed the most up-to-date trends for outpatient TJA and discussed essential factors for a successful outpatient program, including the proper patient selection process and best available anesthetic and analgesic options, along with their risks and benefits. Risk stratification tools, such as the Outpatient Arthroplasty Risk Assessment, are helpful for predicting outcomes regarding outpatient TJA, and neuraxial anesthesia should be considered to minimize complications and facilitate early discharge. A multimodal analgesia regimen could be effective for pain management in outpatient TJA, and the currently recommended peripheral nerve blocks for total hip arthroplasty and total knee arthroplasty are the fascia iliaca compartment block and adductor canal block, respectively. However, blocks should be carefully considered for outpatient procedures. Enhanced recovery after surgery (ERAS) protocols help to guide perioperative care teams and allow for improved patient recovery, decreased length of stay, and increased patient satisfaction.

Abstract
Importance: Gabapentin has been increasingly used as part of a multimodal analgesia regimen to reduce opioid use in perioperative pain management. However, the safety of perioperative gabapentin use among older patients remains uncertain.

Objective: To examine in-hospital adverse clinical events associated with perioperative gabapentin use among older patients undergoing major surgery.

Design, setting, and participants: This retrospective cohort study using data from the Premier Healthcare Database included patients aged 65 years or older who underwent major surgery at US hospitals within 7 days of hospital admission from January 1, 2009, to March 31, 2018, and did not use gabapentin before surgery. Data were analyzed from June 14, 2021, to May 23, 2022.

Exposures: Gabapentin use within 2 days after surgery.

Main outcomes and measures: The primary outcome was delirium, identified using diagnosis codes, and secondary outcomes were new antipsychotic use, pneumonia, and in-hospital death between postoperative day 3 and hospital discharge. To reduce confounding, 1:1 propensity score matching was performed. Risk ratios (RRs) and risk differences (RDs) with 95% CIs were estimated.

Results: Among 967 547 patients before propensity score matching (mean [SD] age, 76.2 [7.4] years; 59.6% female), the rate of perioperative gabapentin use was 12.3% (119 087 patients). After propensity score matching, 237 872 (118 936 pairs) gabapentin users and nonusers (mean [SD] age, 74.5 [6.7] years; 62.7% female) were identified. Compared with nonusers, gabapentin users had increased risk of delirium (4040 [3.4%] vs 3148 [2.6%]; RR, 1.28 [95% CI, 1.23-1.34]; RD, 0.75 [95% CI, 0.75 [0.61-0.89] per 100 persons), new antipsychotic use (944 [0.8%] vs 805 [0.7%]; RR, 1.17 [95% CI, 1.07-1.29]; RD, 0.12 [95% CI, 0.05-0.19] per 100 persons), and pneumonia (1521 [1.3%] vs 1368 [1.2%]; RR, 1.11 [95% CI, 1.03-1.20]; RD, 0.13 [95% CI, 0.04-0.22] per 100 persons), but there was no difference in in-hospital death (362 [0.3%] vs 354 [0.2%]; RR, 1.02 [95% CI, 0.88-1.18]; RD, 0.00 [95% CI, -0.04 to 0.05] per 100 persons). Risk of delirium among gabapentin users was greater in subgroups with high comorbidity burden than in those with low comorbidity burden (combined comorbidity index <4 vs ≥4: RR, 1.20 [95% CI, 1.13-1.27] vs 1.40 [95% CI, 1.30-1.51]; RD, 0.41 [95% CI, 0.28-0.53] vs 2.66 [95% CI, 2.08-3.24] per 100 persons) and chronic kidney disease (absence vs presence: RR, 1.26 [95% CI, 1.19-1.33] vs 1.38 [95% CI, 1.27-1.49]; RD, 0.56 [95% CI, 0.42-0.69] vs 1.97 [95% CI, 1.49-2.46] per 100 persons).

Conclusion and relevance: In this cohort study, perioperative gabapentin use was associated with increased risk of delirium, new antipsychotic use, and pneumonia among older patients after major surgery. These results suggest careful risk-benefit assessment before prescribing gabapentin for perioperative pain management.

Abstract
Importance: Prehabilitation programs for patients undergoing orthopedic surgery have been gaining popularity in recent years. However, the current literature has produced varying results.

Objective: To evaluate whether prehabilitation is associated with improved preoperative and postoperative outcomes compared with usual care for patients undergoing orthopedic surgery.

Data sources: Bibliographic databases (MEDLINE, CINAHL [Cumulative Index to Nursing and Allied Health Literature], AMED [Allied and Complementary Medicine], Embase, PEDRO [Physiotherapy Evidence Database], and Cochrane Central Register of Controlled Trials) were searched for published trials, and the Institute for Scientific Information Web of Science, System for Information on Grey Literature in Europe, and European clinical trials registry were searched for unpublished trials from January 1, 2000, to June 30, 2022.

Study selection: Randomized clinical trials (RCTs) comparing prehabilitation with standard care for any orthopedic surgical procedure were included.

Data extraction and synthesis: Two independent reviewers screened trials. Data were pooled using a random-effects model. Recommendations were determined using the Grading of Recommendations Assessment, Development and Evaluation system and the study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline.

Main outcomes and measures: Pain, function, muscle strength, and health-related quality of life (HRQOL).

Results: Forty-eight unique trials involving 3570 unique participants (2196 women [61.5%]; mean [SD] age, 64.1 [9.1] years) were analyzed. Preoperatively, moderate-certainty evidence favoring prehabilitation was reported for patients undergoing total knee replacement (TKR) for function (standardized mean difference [SMD], -0.70 [95% CI, -1.08 to -0.32]) and muscle strength and flexion (SMD, 1.00 [95% CI, 0.23-1.77]) and for patients undergoing total hip replacement (THR) for HRQOL on the 36-item Short Form Health Survey (weighted mean difference [WMD], 7.35 [95% CI, 3.15-11.54]) and muscle strength and abduction (SMD, 1.03 [95% CI, 0.03-2.02]). High-certainty evidence was reported for patients undergoing lumbar surgery for back pain (WMD, -8.20 [95% CI, -8.85 to -7.55]) and moderate-certainty evidence for HRQOL (SMD, 0.46 [95% CI, 0.13-0.78]). Postoperatively, moderate-certainty evidence favoring prehabilitation was reported for function at 6 weeks in patients undergoing TKR (SMD, -0.51 [95% CI, -0.85 to -0.17]) and at 6 months in those undergoing lumbar surgery (SMD, -2.35 [95% CI, -3.92 to -0.79]). Other differences in outcomes favoring prehabilitation were of low to very low quality of evidence.

Conclusions and relevance: In this systematic review and meta-analysis of RCTs, moderate-certainty evidence supported prehabilitation over usual care in improving preoperative function and strength in TKR and HRQOL and muscle strength in THR, high-certainty evidence in reducing back pain, and moderate-certainty evidence in improving HRQOL in lumbar surgery. Postoperatively, moderate-certainty evidence supported prehabilitation for function following TKR at 6 weeks and lumbar surgery at 6 months. Prehabilitation showed promising results for other outcomes, although high risk of bias and heterogeneity affected overall quality of evidence. Additional RCTs with a low risk of bias investigating preoperative and postoperative outcomes for all orthopedic surgical procedures are required.

Abstract
Regional analgesia has been introduced successfully into the postoperative pain management after total knee arthroplasty, reducing pain scores, opioid use and adverse effects. Combination of regional analgesia techniques is associated with better pain management and lower side effects than single regional techniques. Adductor canal block provides good analgesia and considerably lower detrimental effect in muscular strength than femoral nerve block, enhancing surgical recovery. Infiltration techniques may have equivalent analgesic effect than epidural analgesia and peripheral nerve blocks, however there should be awareness of dose dependent toxicity. Novel long-acting local anesthetics role for regional analgesia is still to be determined, and will require larger randomized trials to support its advantage over traditional local anesthetics.

Abstract
Background: Approximately 23% of patients develop hip pain after total hip arthroplasty (THA). In this systematic review, we aimed to identify risk factors associated with postoperative pain after THA to optimize preoperative surgical planning.

Methods: Six literature databases were searched for articles published from January 1995 to August 2020. Controlled trials and observational studies that reported measurements of postoperative pain with assessments of preoperative modifiable and non-modifiable risk factors were included. Three researchers performed a literature review independently.

Results: Fifty-four studies were included in the study for analysis. The most consistent association between worse pain outcomes and the female sex is poor preoperative pain or function, and more severe medical or psychiatric comorbidities. The correlation was less strong between worse pain outcomes and preoperative high body mass index value, low radiographic grade arthritis, and low socioeconomic status. A weak correlation was found between age and worse pain outcomes.

Conclusions: Preoperative risk factors that were consistently predictive of greater/server postoperative pain after THA were identified, despite the varying quality of studies that prohibited the arrival of concrete conclusions. Modifiable factors should be optimized preoperatively, whereas non-modifiable factors may be valuable to patient education, shared decision-making, and individualized pain management.