Pain Management Associated with Total Joint Arthroplasty: A Primer

One Size Does Not Fit All: Women Experience More Pain Than Men After Total Knee Arthroplasty

BACKGROUND

Multimodal pain regimens are universally applied to all patients, despite known differences in pain and responses to medication between patients of different sexes, ethnicities, and races. The purpose of this study was to understand the influence of patient sex on postoperative total knee arthroplasty pain perception as well as the efficacy of perioperative pregabalin for pain control.

METHODS

Visual analog Scales (VASs) and Knee Injury and Osteoarthritis Outcome Junior (KOOS Jr.) scores were prospectively collected for 150 patients (64 men and 86 women). Mean pain scores, delta pain scores, time to achieve minimal clinically important differences, influence of pregabalin, and opioid consumption were recorded at baseline, day of surgery, 24 hours, 48 hours, and 72 hours postoperatively, as well as postoperatively weeks 1, 2, 6, 12, and 26, and compared between women and men cohorts. This study was registered on ClinicalTrials.gov (NCT04471233).

RESULTS

The VAS pain scores for women were higher than for men at all study time points (P < 0.05). The change in VAS walking and mean KOOS Jr. scores from baseline to final follow-up at 26 weeks were not significantly different between cohorts. Both cohorts achieved VAS minimal clinically important difference by 2 weeks postoperatively. No significant differences in opioid consumption between men and women were noted during the study time periods. Women were also noted to have significantly higher raw KOOS Jr. scores than men at all-time points, except for at 26 weeks postoperatively. Interim analysis revealed no significant influence of pregabalin on VAS scores, so this arm of the study was discontinued.

CONCLUSIONS

Patient sex plays a role in perceived postoperative total knee arthroplasty pain, as women reported higher pain scores than men. We recommend not overly relying on standardized protocols, but rather instituting patient-specific pain management strategies.

The Effect of Music on Postoperative Agitation, Pain, and Opioid Use among Patients Undergoing Total Knee Replacement

BACKGROUND

Postoperative pain and agitation is an ongoing issue among patients undergoing total knee replacement (TKR). Use of complementary therapies such as music may improve outcomes when combined with medical therapy.

AIM

The purpose of this quality improvement (QI) initiative was to evaluate postoperative use of classical music among adult patients who have undergone TKR on reported agitation, pain, and opioid use.

DESIGN

A prospective evidence-based QI initiative.

SETTING

A midwestern hospital post-anesthesia care unit.

PARTICIPANTS

Postoperative patients who had undergone TKR.

METHODS

Classical piano music was played postoperatively using an MP3 device. Adult patients who were undergoing TKR were consecutively offered music during their recovery period in the PACU. Agitation was measured using the Richmond Agitation Sedation Score (RASS). Patient perceived pain was measured on a scale of 0-10 with 0 being no pain and 10 being extreme pain. Opioid use was measured using the morphine milligram equivalents (MME).

FINDINGS

A total of (n=40) patients received music and (n=50) patients received standard care without music. RASS was significantly lower in the music group than in the baseline non-music group X2 (1, N = 89) = 17.8, p < .001. Patient reported pain scores were significantly lower in the music group, 3.98(SD = 2.71), compared to the baseline non-music group, 6.27(SD = 2.60). Opioid use was also significantly decreased in the music group to MME 9.51(SD = 8.62) compared to the baseline non-music group 13.38 (SD = 9.71).

CONCLUSION

Music is an effective nonpharmacologic intervention in decreasing agitation, pain, and opioid use among patients undergoing TKR. These findings provide evidence for nurses to incorporate music as an adjunctive approach to enhance the patient's experience and improve outcomes.

Assessing pain management in total joint arthroplasty using the Detroit interventional pain assessment scale-A prospective cohort study

BACKGROUND

Total joint arthroplasty (TJA) is an effective treatment for end-stage osteoarthritis, but postoperative pain has been poorly managed. The purpose of this study was to (1) assess how much narcotic medication was prescribed after TJA; (2) assess if patients were satisfied with their pain management; (3) compare these same data between total hip arthroplasty (THA)/total knee arthroplasty (TKA); (4) compare these same data between preoperative opioid users/opioid-naïve patients.

METHODS

An IRB-approved prospective study was conducted at a US academic joint replacement practice. Patients were evaluated by an independent observer at three weeks, three months, and six months postoperatively using the Detroit Interventional Pain Assessment (DIPA) scale. Patients verbally rated their pain with their current medication regimen as 0 (no pain), 1 (tolerable pain), or 2 (intolerable pain) on the DIPA scale. Narcotic usage was verified by the Michigan Automated Prescription System (MAPS). Patients were divided into THA, TKA, previously on opioids, and opioid-naïve groups. Provider efficiency scores reflected pain management satisfaction and were calculated as the percentage of patients reporting no pain or tolerable pain.

RESULTS

Out of 200 patients, the percentage of patients using narcotics and their daily usage (MMEs) significantly decreased from 75.5% (27.5 MMEs) at three weeks to 42.9% (5.3 MMEs) at six months (P < 0.001). In 80% of patients, narcotics taken at six months were prescribed by outside providers. Significantly fewer patients used narcotics at six months for THA (15.4%) compared to TKA (52.7%) (P < 0.021). There was a significant difference in daily narcotic usage between patients who took narcotics preoperatively (22.9 MMEs) and opioid-naïve ones (13.4 MMEs) (P < 0.001). Provider efficiency scores were best at three weeks (76.6%) and three months (70%) but declined at six months (57.2%).

CONCLUSIONS

Narcotic tapering practices were observed as postoperative daily narcotic intake decreased across six months. However, outside providers prescribed 80% of narcotics at six months, necessitating a better-coordinated practice with surgeons. Patients taking preoperative narcotics experienced higher daily MME requirements than their opioid-naïve counterparts. In terms of the percentage of patients on narcotics, THA is a better procedure for tapering patients off narcotics by six months.

Management of Acute Surgical Pain in Plastic and Reconstructive Surgery

SUMMARY

Fewer than half of all patients undergoing surgery report adequate postoperative pain relief. Poorly managed postoperative pain can lead to complications, increased hospital stays, prolonged rehabilitation, and a decreased quality of life. Pain rating scales are commonly used to identify, manage, and track the perceived intensity of pain. Changes in perceived pain severity and intensity are a key indicator for course of treatment. Postoperative pain is best treated with multimodal management with a variety of analgesic medications and techniques that target different receptors and mechanisms of action in the peripheral and central nervous systems. This includes systemic analgesia, regional analgesia, local analgesia (eg, topical and tumescent analgesia), and nonpharmacologic modalities. It is recommended that this approach is individually tailored and discussed through a shared decision-making approach. This review provides an overview of multimodal management for acute postoperative pain related to plastic surgery procedures. To increase patient satisfaction and provide effective pain control, it is recommended to educate patients on expectations of pain, multimodal options for pain control (including peripheral nerve blocks), complications of unrelieved pain, tracking and monitoring of pain by self-reporting, and how to reduce the use of opioid-based pain medication.

Acute Perioperative Pain Management of the Orthopaedic Patient: Guidance for Operationalizing Evidence Into Practice

Orthopaedic surgery often results in pain, with less than half of patients reporting adequate relief. Unrelieved acute pain occurring after surgery increases the risk of negative sequelae, including delayed healing, increased morbidity, pulmonary complications, limited rehabilitation participation, anxiety, depression, increased length of stay, prolonged duration of opioid use, and the development of chronic pain. Interventions that are individualized, evidence-informed, and applied within an ethical framework improve healthcare delivery for patients, clinicians, and healthcare organizations. Recommendations for using the principles of effective pain management from preoperative assessment through discharge are detailed, including recommendations for addressing barriers and challenges in applying these principles into clinical practice.

Comparative analysis of lumbar quadratus lumborum block and epidural block for analgesia in uterine surgery at Dr. Soetomo Hospital, Surabaya

Over 80% of surgical patients experience postoperative pain, which, if inadequately managed, can lead to complications, prolonged rehabilitation, chronic pain, and decreased quality of life. Epidural block and quadratus lumborum block are techniques commonly used for postoperative pain management. This comparative analytic study aimed to analyze the differences in the analgesic effects of quadratus lumborum block and epidural block in uterine surgery at Dr. Soetomo General Hospital. The outcomes assessed were the numerical rating score (NRS) as a pain score and the administration of opioids as an adjuvant analgesic. Statistical analysis employed the Mann-Whitney test and Chi-square test. The study included 32 patients who underwent uterine surgery at Dr. Soetomo General Hospital and met the inclusion and exclusion criteria. Among the patients, 90.6% experienced mild pain, and 9.4% experienced moderate pain. Epidural blocks were performed in 50% of the patients, while quadratus lumborum blocks were performed in the other 50%. Additionally, 9.4% of the patients received opioids as adjuvant analgesics. The Mann-Whitney test revealed no significant difference in NRS between the epidural block and quadratus lumborum block groups (p-value>0.05). However, the Chi-square test indicated a significant difference in NRS between patients who received additional opioids as adjuvant analgesics and those who did not (p-value<0.00). There was no significant difference in NRS between patients who underwent epidural block and quadratus lumborum block as analgesic techniques.

Body Habitus Impact on Success of Cryoneurolysis for Postoperative Total Knee Arthroplasty Pain Control: A Retrospective Cohort Study

Background

Cryoneurolysis utilizes temperatures below -20°C for nonpermanent analgesia to control pain in total knee arthroplasty (TKA). There is concern that body habitus could limit pain control because of accuracy of cryoneurolysis to subcutaneous nerves. This study aimed to determine the relationship between body habitus and effectiveness of cryoneurolysis on postoperative pain control.

Methods

A retrospective chart review was performed on patients undergoing cryoneurolysis before primary TKA from 2017 to 2019. Included were 114 patients (58 control group and 56 treatment group). Cryoneurolysis patients were divided into 3 groups (small, medium, and large) based on the soft tissue to femoral diaphysis ratio of 7 cm proximal to superior pole of the patella. Postoperative outcome measures were morphine equivalents, numerical rating score for pain, range of motion, and Knee Injury and Osteoarthritis Outcome Score Joint Replacement.

Results

The small cryoneurolysis group showed decreased opioid consumption at the 2, 6, and 12 weeks compared with control group, with morphine equivalents significantly decreased at 2 weeks for small compared with medium groups (54.3 vs 142.9, P = .0097). Numerical rating score for pain decreased significantly between small and medium groups (3.4 vs 4.0, P = .012) and between medium and large groups (4.0 vs 2.4, P = .012). Range of motion increased at 12 weeks for small group compared with medium group (118 vs 112, P = .042). There were no differences in any outcome measure between small and large groups.

Conclusions

Body habitus does not appear to affect efficacy of cryoneurolysis in controlling postoperative pain following TKA. Cryoneurolysis remains a useful tool for multimodal pain management.

Positive Association between Peri-Surgical Opioid Exposure and Post-Discharge Opioid-Related Outcomes

Background: Multiple studies have investigated the epidemic of persistent opioid use as a common postsurgical complication. However, there exists a knowledge gap in the association between the level of opioid exposure in the peri-surgical setting and post-discharge adverse outcomes to patients and healthcare settings. We analyzed the association between peri-surgical opioid exposure use and post-discharge outcomes, including persistent postsurgical opioid prescription, opioid-related symptoms (ORS), and healthcare resource utilization (HCRU). Methods: A retrospective cohort study included patients undergoing cesarean delivery, hysterectomy, spine surgery, total hip arthroplasty, or total knee arthroplasty in an academic healthcare system between January 2015 and June 2018. Peri-surgical opioid exposure was converted into morphine milligram equivalents (MME), then grouped into two categories: high (>median MME of each surgery cohort) or low (≤median MME of each surgery cohort) MME groups. The rates of persistent opioid use 30 and 90 days after discharge were compared using logistic regression. Secondary outcomes, including ORS and HCRU during the 180-day follow-up, were descriptively compared between the high and low MME groups. Results: The odds ratios (95% CI) of high vs. low MME for persistent opioid use after 30 and 90 days of discharge were 1.38 (1.24−1.54) and 1.41 (1.24−1.61), respectively. The proportion of patients with one or more ORS diagnoses was greater among the high-MME group than the low-MME group (27.2% vs. 21.2%, p < 0.01). High vs. low MME was positively associated with the rate of inpatient admission, emergency department admissions, and outpatient visits. Conclusions: Greater peri-surgical opioid exposure correlates with a statistically and clinically significant increase in post-discharge adverse opioid-related outcomes. The study findings warrant intensive monitoring for patients receiving greater peri-surgical opioid exposure.

Admission NarxCare Narcotic Scores Are Associated With Increased Odds of Readmission and Prolonged Length of Hospital Stay After Primary Elective Total Knee Arthroplasty

INTRODUCTION

The association of preoperative narcotic use with postoperative outcomes after primary elective total knee arthroplasty (TKA) has remained poorly characterized. The NarxCare platform analyzes patients' state Prescription Drug Monitoring Program records to assign numerical scores that approximate a patient's overall opioid usage. The present study investigated the utility of admission NarxCare narcotic scores in predicting the odds of adverse events (AEs) after primary elective TKA.

METHODS

Elective primary TKA patients performed at a single institution between October 2017 and May 2020 were evaluated. NarxCare narcotic scores at the time of admission, patient characteristics, 30-day AEs, readmissions, revision surgeries, and mortality were abstracted. Elective TKA patients were binned based on admission NarxCare narcotic scores. The odds of experiencing adverse outcomes were compared.

RESULTS

In total, 1136 patients met the criteria for inclusion in the study (Narx Score 0: n = 293 [25.8%], 1 to 99: n = 253 [22.3%], 100 to 299: n = 368 [32.4%], 300 to 499: n = 161 [14.2%], and 500+: n = 61 [5.37%]). By logistic regression, patients with higher admission narcotic scores tended to have a dose-dependent increase in the odds of prolonged length of hospital stay, readmission within 30 days, and aggregated AEs.

DISCUSSION

Admission narcotic scores may be used to predict readmission and to stratify TKA patients by risk of AEs.

The m6A demethylase FTO promotes the osteogenesis of mesenchymal stem cells by downregulating PPARG

N⁶-methyladenosine (m⁶A) is the most abundant posttranscriptional methylation modification that occurs in mRNA and modulates the fine-tuning of various biological processes in mammalian development and human diseases. In this study we investigated the role of m⁶A modification in the osteogenesis of mesenchymal stem cells (MSCs), and the possible mechanisms by which m⁶A modification regulated the processes of osteoporosis and bone necrosis. We performed systematic analysis of the differential gene signatures in patients with osteoporosis and bone necrosis and conducted m⁶A-RNA immunoprecipitation (m⁶A-RIP) sequencing to identify the potential regulatory genes involved in osteogenesis. We showed that fat mass and obesity (FTO), a primary m⁶A demethylase, was significantly downregulated in patients with osteoporosis and osteonecrosis. During the differentiation of human MSCs into osteoblasts, FTO was markedly upregulated. Both depletion of FTO and application of the FTO inhibitor FB23 or FB23-2 impaired osteogenic differentiation of human MSCs. Knockout of FTO in mice resulted in decreased bone mineral density and impaired bone formation. PPARG, a biomarker for osteoporosis, was identified as a critical downstream target of FTO. We further revealed that FTO mediated m⁶A demethylation in the 3'UTR of PPARG mRNA, and reduced PPARG mRNA stability in an YTHDF1-dependent manner. Overexpression of PPARG alleviated FTO-mediated osteogenic differentiation of MSCs, whereas knockdown of PPARG promoted FTO-induced expression of the osteoblast biomarkers ALPL and OPN during osteogenic differentiation. Taken together, this study demonstrates the functional significance of the FTO-PPARG axis in promoting the osteogenesis of human MSCs and sheds light on the role of m⁶A modification in mediating osteoporosis and osteonecrosis.

Association of Acute Postoperative Pain and Cigarette Smoking With Cerebrospinal Fluid Levels of Beta-Endorphin and Substance P

Objectives: Cigarette smoking is associated with postoperative pain perception, which might be mediated by beta-endorphin and substance P. These effects on postoperative pain perception have never been investigated in human cerebrospinal fluid (CSF), which reflects biochemical alterations in the brain. Therefore, we investigated the associations among cigarette smoking, postoperative pain, and levels of beta-endorphin and substance P in human CSF. Methods: We recruited 160 Chinese men (80 active smokers and 80 nonsmokers) who underwent lumbar puncture before anterior cruciate ligament reconstruction, and 5-ml CSF samples were collected. Pain visual analog scale (VAS) scores, post-anesthetic recovery duration (PARD), and smoking variables were obtained. CSF levels of beta-endorphin and substance P were measured. Results: Compared to non-smokers, active smokers had significantly higher pain VAS (2.40 ± 0.67 vs. 1.70 ± 0.86, p < 0.001) and PARD scores (9.13 ± 2.11 vs. 7.27 ± 1.35, p = 0.001), lower CSF beta-endorphin (33.76 ± 1.77 vs. 35.66 ± 2.20, p = 0.001) and higher CSF substance P (2,124.46 ± 217.34 vs. 1,817.65 ± 302.14, p < 0.001) levels. Pain VAS scores correlated with PARD in active smokers (r = 0.443, p = 0.001). Conclusions: Cigarette smoking is associated with increased postoperative pain intensity, shown by delayed pain perception, higher pain VAS scores, and lower beta-endorphin and higher substance P levels in the CSF of active smokers. The more extended postoperative pain perception is delayed, the more pain intensity increases.

Avascular necrosis after femoral neck fracture in children and adolescents: poor prognosis and risk factors

INTRODUCTION

Avascular necrosis (AVN) after femoral neck fracture (FNF) is a rare and severe paediatric condition, but only few studies described its prognosis and risk factors. The present study aimed to evaluate the outcomes and independent factors for poor prognosis of AVN after FNF in children and adolescents.

METHOD

This retrospective study included children and adolescents with AVN after FNF who received conservative treatment (CT group) or non-vascularized bone grafting (NVBG group) between 2000 and 2018. The primary outcomes were the risk of hip arthritis (Tönnis grade) and hip deformity risk (Stulberg classification). All patients were followed for at least two years to assess AVN progression.

RESULTS

Study included 81 patients. In the CT group, 23/43 patients (53.4%) developed hip arthritis, and 24/43 patients (55.8%) showed hip deformity. In the NVBG group, 23/38 patients (60.5%) developed hip arthritis, and 34/38 patients (89.5%) had a hip deformity. The multivariable analysis indicated that NVBG surgery had no significant effect on the outcomes. Post-treatment femoral head collapse (P = 0.05, OR = 3.80, 95% CI = 1.01-14.29) and post-treatment hip subluxation (P = 0.01, OR = 2.85, 95% CI = 2.31-129.56) were independent risk factors for severe hip arthritis. Post-treatment femoral head collapse (P < 0.01, OR = 7.64, 95% CI = 3.23-18.04) and pre-treatment hip subluxation (P = 0.02, OR = 7.33, 95% CI = 1.44-37.41) were independent risk factors for severe hip deformity.

CONCLUSION

Neither CT nor NVBG have demonstrated superiority regarding long-term outcomes in patients with AVN after FNF. Upon the disease progression to severe collapse with subluxation and severe arthritis, further hip preservation attempts could be futile.

Economic Impact of Preoperative Meloxicam IV Administration in Total Knee Arthroplasty: A Randomized Trial Sub-Study

We evaluated the economic impact associated with preoperative meloxicam IV 30 mg vs placebo administration among adult total knee arthroplasty (TKA) recipients enrolled in Phase IIIB NCT03434275 trial. Data on total hospital costs and length of stay (LOS) obtained from the trial were compared between meloxicam IV 30 mg and placebo groups. Patients in the meloxicam IV 30 mg vs placebo group (n = 93 vs 88) incurred an adjusted $2,266 (95% CI: -$1,035, $5,116; p = 0.1689) lower total hospital costs and an adjusted 8.6% (95% confidence interval [CI]: -2.0%, 18.1%; p = 0.1082) shorter LOS. While statistically non-significant, based on 95% CIs, the results from this sub-study may suggest a favorable impact associated with meloxicam IV 30 mg on hospital costs and LOS.

Safety and Efficacy of Perioperative Intravenous Meloxicam for Moderate-to-Severe Pain Management in Total Knee Arthroplasty: A Randomized Clinical Trial

Objective

To evaluate the effect of perioperative meloxicam IV 30 mg on opioid consumption in primary total knee arthroplasty (TKA).

Design

Multicenter, randomized, double-blind, placebo-controlled trial.

Subjects

In total, 181 adults undergoing elective primary TKA.

Methods

Subjects received meloxicam 30 mg or placebo via an IV bolus every 24 hours, the first dose administered prior to surgery as part of a multimodal pain management protocol. The primary efficacy parameter was total opioid use from end of surgery through 24 hours.

Results

Meloxicam IV was associated with less opioid use versus placebo during the 24 hours after surgery (18.9 ± 1.32 vs 27.7 ± 1.37 mg IV morphine equivalent dose; P < 0.001) and was superior to placebo on secondary endpoints, including summed pain intensity (first dose to 24 hours postdosing, first dose to first assisted ambulation, and first dose to discharge) and opioid use (48–72 hrs., 0–48 hrs., 0–72 hrs., hour 0 to end of treatment, and the first 24 hours after discharge). Adverse events (AEs) were reported for 69.9% and 92.0% of the meloxicam IV and placebo groups, respectively; the most common AEs were nausea (40% vs. 59%), vomiting (16% vs 22%), hypotension (14% vs 15%), pruritus (15% vs 11%), and constipation (11% vs 13%).

Conclusions

Perioperative meloxicam IV 30 mg as part of a multimodal analgesic regimen for elective primary TKA reduced opioid consumption in the 24-hour period after surgery versus placebo and was associated with a lower incidence of AEs typically associated with opioid use.

Management of Refractory Pain After Total Joint Replacement

PURPOSE OF REVIEW

Chronic pain after total joint replacement (TJA), specifically total knee replacement (TKA), is becoming more of a burden on patients, physicians, and the healthcare system as the number of joint replacements performed increases year after year. The management of this type of pain is critical, and therefore, understanding the various modalities physicians can use to help patients with refractory pain after TJA is essential.

RECENT FINDINGS

The modalities by which chronic pain can be successfully managed include genicular nerve radioablation therapy (GN-RFA), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and peripheral subcutaneous field stimulation (PSFS). Meta-analyses and case reports have demonstrated the effectiveness of these treatment options in improving pain and functional outcomes in patients with chronic pain after TKA. The purpose of this paper is to review and synthesize the current literature investigating the different ways that refractory pain is managed after TJA, with the goal being to provide treatment recommendations for providers treating these patients.

Robotic Total Knee Arthroplasty vs Conventional Total Knee Arthroplasty: A Nationwide Database Study

Background

As robot-assisted equipment is continuously being used in orthopaedic surgery, the past few decades have seen an increase in the usage of robotics for total knee arthroplasty (TKA). Thus, the purpose of the present study is to investigate the differences between robotic TKA and nonrobotic TKA on perioperative and postoperative complications and opioid consumption.

Methods

An administrative database was queried from 2010 to Q2 of 2017 for primary TKAs performed via robot-assisted surgery vs non-robot-assisted surgery. Systemic and joint complications and average morphine milligram equivalents were collected and compared with statistical analysis.

Results

Patients in the nonrobotic TKA cohort had higher levels of prosthetic revision at 1-year after discharge (P < .05) and higher levels of manipulation under anesthesia at 90 days and 1-year after discharge (P < .05). Furthermore, those in the nonrobotic TKA cohort had increased occurrences of deep vein thrombosis, altered mental status, pulmonary embolism, anemia, acute renal failure, cerebrovascular event, pneumonia, respiratory failure, and urinary tract infection during the inpatient hospital stay (all P < .05) and at 90 days after discharge (all P < .05). All of these categories remained statistically increased at the 90-days postdischarge date, except pneumonia and stroke. Patients in the nonrobotic TKA cohort had higher levels of average morphine milligram equivalents consumption at all time periods measured (P < .001).

Conclusions

In the present study, the use of robotics for TKA found lower revision rates, lower incidences of manipulation under anesthesia, decreased occurrence of systemic complications, and lower opiate consumption for postoperative pain management. Future studies should look to further examine the long-term outcomes for patients undergoing robot-assisted TKA.

Level of Evidence

Level III.

Fascia iliaca compartment block for analgesia in total hip replacement: A randomized controlled study protocol

BACKGROUND

Pain management after the total joint arthroplasty is still challenging, but worthy of attention, because good pain management can improve the outcomes of patient. It is still controversial whether fascia iliaca compartment block (FICB) can effectively decrease the opioid consumption and pain after total hip replacement (THR) owing to the number of published investigations is small. The purpose of this present study is to assess the efficacy and safety of FICB for postoperative analgesia after THR.

METHODS

This is a single center, placebo-controlled randomized trial which is performed in accordance with the SPIRIT Checklist for randomized studies. It was authorized via the Chifeng Municipal Hospital institutional review committee (H2020-19-8). 100 patients undergoing THR will be included in this study. Patients are randomly divided into 2 groups: FICB group or Non-FICB group, FICB with 5mgmL of epinephrine and 40 mL of ropivacaine 0.2%. Primary outcomes are pain score at different time point. Visual analog scale is used to assess the pain (10: the maximum possible pain and 0: absent pain). The secondary outcomes are the postoperative complications, length of hospital stay and total consumption of opioid. All the needed analyses are implemented through utilizing SPSS for Windows Version 15.0.

RESULTS

Figure 1 will show the primary and secondary outcomes.

CONCLUSION

This trial can provide an evidence for the use of FICB for analgesia after THR.

Development and validation of machine learning algorithms for postoperative opioid prescriptions after TKA

Objective

The aims of this study were to develop machine learning algorithms for preoperative prediction of prolonged opioid prescriptions after TKA and to identify variables that can predict the probability of this adverse outcome.

Methods

Five algorithms were developed for prediction of prolonged postoperative opioid prescriptions.

Results

The stochastic gradient boosting (SGB) model had the best performance. Age, history of preoperative opioid use, marital status, diagnosis of diabetes, and several preoperative medications were predictive of prolonged postoperative opioid prescriptions.

Conclusion

The SGB algorithm developed could help improve preoperative identification of TKA patients at risk for prolonged postoperative opioid prescriptions.