Mechanical and suboptimal pharmacologic prophylaxis and delayed mobilization but not morbid obesity are associated with venous thromboembolism after total knee arthroplasty: a case-control study

Are Patients With Morbid Obesity at Increased Risk of Pulmonary Embolism or Proximal Deep Vein Thrombosis After Lower Limb Arthroplasty? A Large-database Study

BACKGROUND

Whether increased BMI is associated with an increased risk of venous thromboembolism (VTE) is controversial. Despite this, BMI > 40 kg/m 2 remains a common cutoff for lower limb arthroplasty eligibility. Current United Kingdom national guidelines list obesity as a risk factor for VTE, but these are based on evidence that has largely failed to differentiate between potentially minor (distal deep vein thrombosis [DVT]), and more harmful (pulmonary embolism [PE] and proximal DVT) diagnoses. Determining the association between BMI and the risk of clinically important VTE is needed to improve the utility of national risk stratification tools.

QUESTIONS/PURPOSES

(1) In patients undergoing lower limb arthroplasty, is BMI 40 kg/m 2 or higher (morbid obesity) associated with an increased risk of PE or proximal DVT within 90 days of surgery, compared with patients with BMI less than 40 kg/m 2 ? (2) What proportion of investigations ordered for PE and proximal DVT were positive in patients with morbid obesity who underwent lower limb arthroplasty compared with those with BMI less than 40 kg/m 2 ?

METHODS

Data were collected retrospectively from the Northern Ireland Electronic Care Record, a national database recording patient demographics, diagnoses, encounters, and clinical correspondence. Between January 2016 and December 2020, 10,217 primary joint arthroplasties were performed. Of those, 21% (2184 joints) were excluded; 2183 were in patients with multiple arthroplasties and one had no recorded BMI. All 8033 remaining joints were eligible for inclusion, 52% of which (4184) were THAs, 44% (3494) were TKAs, and 4% (355) were unicompartmental knee arthroplasties; all patients had 90 days of follow-up. The Wells score was used to guide the investigations. Indications for CT pulmonary angiography for suspected PE included pleuritic chest pain, reduced oxygen saturations, dyspnea, or hemoptysis. Indications for ultrasound scans for suspected proximal DVT included leg swelling, pain, warmth, or erythema. Distal DVTs were recorded as negative scans because we do not treat them with modified anticoagulation. The division of categories was set at BMI 40 kg/m 2 , a common clinical cutoff used in surgical eligibility algorithms. Patients were grouped according to WHO BMI categories to assess for the following confounding variables: sex, age, American Society of Anesthesiologists grade, joint replaced, VTE prophylaxis, grade of operative surgeon, and implant cement status.

RESULTS

We found no increase in the odds of PE or proximal DVT in any WHO BMI category. When comparing patients with BMI less than 40 kg/m 2 with those with a BMI of 40 kg/m 2 or higher, there was no difference in the odds of PE (0.8% [58 of 7506] versus 0.8% [four of 527]; OR 1.0 [95% CI 0.4 to 2.8]; p > 0.99) or proximal DVT (0.4% [33 of 7506] versus 0.2% [one of 527]; OR 2.3 [95% CI 0.3 to 17.0]; p = 0.72). Of those who received diagnostic imaging, 21% (59 of 276) of CT pulmonary angiograms and 4% (34 of 718) of ultrasounds were positive for patients with BMI less than 40 kg/m 2 compared with 14% (four of 29; OR 1.6 [95% CI 0.6 to 4.5]; p = 0.47) and 2% (one of 57; OR 2.7 [95% CI 0.4 to 18.6]; p = 0.51) for patients with BMI 40 kg/m 2 or higher. There was no difference in the percentage of CT pulmonary angiograms ordered (4% [276 of 7506] versus 5% [29 of 527]; OR 0.7 [95% CI 0.5 to 1.0]; p = 0.07) or ultrasounds ordered (10% [718 of 7506] versus 11% [57 of 527]; OR 0.9 [95% CI 0.7 to 1.2]; p = 0.49) for BMI less than 40 kg/m 2 and BMI 40 kg/m 2 or higher.

CONCLUSION

Increased BMI should not preclude individuals from lower limb arthroplasty based on suspected risk of clinically important VTE. National VTE risk stratification tools should be based on evidence assessing clinically relevant VTE (specifically, proximal DVT, PE, or death of thromboembolism) only.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Operative Techniques to Reduce Hip and Knee Arthroplasty Complications in Morbidly Obese Patients

Obesity, defined as a body mass index (BMI) >30, is associated with an increased likelihood of osteoarthritis and need for total joint arthroplasty (TJA). Unfortunately, the morbidly obese population has a higher risk of postoperative complications. For some surgeons, patient selection criteria for TJA includes BMI<40. The associated risks are recognized by The American Association of Hip And Knee Surgeons, and many surgeons follow these guidelines. Importantly, as obese patients have been demonstrated to have equal or greater gains in functional outcomes and quality of life metrics, it is important for obese patients to have access to TJA. Through a comprehensive literature review and structured interviews with leading surgeons in the field, we provide guidance for orthopedic surgeons treating patients with BMI>40 to minimize risks, including tailored preoperative, intraoperative, and postoperative considerations.

Guideline No. 417: Prevention of Venous Thromboembolic Disease in Gynaecological Surgery

OBJECTIVE

The primary objective of this clinical practice guideline is to provide gynaecologists with an algorithm and evidence to guide the use of thromboprophylaxis in gynaecological surgery.

TARGET POPULATION

All patients undergoing gynaecological surgery for benign or malignant indications.

BENEFITS, HARMS, AND COSTS

The implementation of this guideline will benefit patients undergoing gynaecological surgery and provide physicians with a standard algorithm for the use of perioperative thromboprophylaxis.

EVIDENCE

The following search terms were entered into MEDLINE, Google Scholar, and Cochrane in 2017 and 2018: VTE, PE, DVT, thromboprophylaxis, gynaecological surgery, heparin, graduated compression stocking, intermittent pneumatic stocking, obesity, pediatrics, minimally invasive surgery, heparin induced thrombocytopenia, regional anesthesia). Articles included were randomized controlled trials, meta-analyses, systematic reviews, and observational studies. Additional publications were identified from the reference lists of these articles. There were no date limits, but search results were limited to English language articles only. Searches were updated and incorporated into the guideline up to September 2018.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED USERS

Gynaecologists and other members of the surgical team. RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).

Morbid obesity is not a contraindication to lower limb arthroplasty

There are concerns that increased BMI is associated with a greater length of stay (LOS) and perioperative complications following total knee (TKR) and total hip replacements (THR). We analysed data from a six-month period to see if there was a correlation between BMI and LOS. We performed a subgroup analysis for patients with morbid obesity (BMI >40) looking at perioperative complications. 285 TKRs and 195 THRs were analysed. For TKRs, the average length of stay was 2.7 days. The average BMI was 32.4. There was no significant correlation between BMI and LOS (r=-0.0447, p=0.2267). The morbidly obese category (n=33) had the shortest LOS (2.5 days) compared to other BMI categories. 30- day readmission rate was 6%. 90-day re-admission rate was 12%. Six patients had minor wound issues requiring no intervention or antibiotics only. The was one prosthetic joint infection, one stitch abscess, one DVT and one patellar tendon injury. For THRs, the average LOS was 2.9 days. The average BMI was 29.9. There was no significant correlation between BMI and LOS (r=0.007, p=0.4613). The morbid obese category (n=9) had the shortest LOS (1.9 days) compared to other BMI categories. No patients were readmitted within 90 days or had documented complications. We have shown that for TKRs and THRs, increased BMI is not associated with increased LOS. The morbidly obese were found to have the shortest LOS. Re-admission rates and complications were commendable for patients with morbid obesity. BMI >40 is not a contraindication to TKR or THR.

Risk Factors Associated With Early Postoperative Respiratory Failure: A Matched Case-Control Study

BACKGROUND

Postoperative respiratory failure is the most common serious postoperative pulmonary complication, yet little is known about factors that can reduce its incidence. We sought to elucidate modifiable factors associated with respiratory failure that developed within the first 5 d after an elective operation.

MATERIALS AND METHODS

Matched case-control study of adults who had an operation at five academic medical centers between October 1, 2012 and September 30, 2015. Cases were identified using administrative data and confirmed via chart review by critical care clinicians. Controls were matched 1:1 to cases based on hospital, age, and surgical procedure.

RESULTS

Our total sample (n = 638) was 56.4% female, 71.3% white, and had a median age of 62 y (interquartile range 51, 70). Factors associated with early postoperative respiratory failure included male gender (odds ratio [OR] 1.72, 95% confidence interval [CI] 1.12-2.63), American Society of Anesthesiologists class III or greater (OR 2.85, 95% CI 1.74-4.66), greater number of preexisting comorbidities (OR 1.14, 95% CI 1.004-1.30), increased operative duration (OR 1.14, 95% CI 1.06-1.22), increased intraoperative positive end-expiratory pressure (OR 1.23, 95% CI 1.13-1.35) and tidal volume (OR 1.13, 95% CI 1.004-1.27), and greater net fluid balance at 24 h (OR 1.17, 95% CI 1.07-1.28).

CONCLUSIONS

We found greater intraoperative ventilator volume and pressure and 24-h fluid balance to be potentially modifiable factors associated with developing early postoperative respiratory failure. Further studies are warranted to independently verify these risk factors, explore their role in development of early postoperative respiratory failure, and potentially evaluate targeted interventions.

Prophylactic Enoxaparin Dosing in Obese Orthopedic Patients: A Literature Search

Objective: The objective of the study was to review the current literature for prophylactic enoxaparin dosing in obese orthopedic patients. Method: A literature search was undertaken using OVID Medline, OVID Embase, and Cochrane Central databases, accessed through hospital library websites. Key search terms (in UK and US spelling) included orthopaedics, low-molecular-weight heparin, enoxaparin, venous thromboembolism prophylaxis, weight, obese, morbid obesity. Possible related subheadings, such as bone, fractures, anticoagulants, overweight, body mass index, deep vein thrombosis, pulmonary embolism, were also included in the database search to optimize the search strategies. The search was restricted to human subjects and limited to articles published from 1998 to the present. Results: The search identified 429 potentially relevant articles. Once duplicates were removed, 345 were screened for inclusion in this review. Only 3 articles (a case-control study, an observational prospective study, and a case report) met both the inclusion and exclusion criteria. The findings from this review need to be interpreted cautiously due to limitations in study designs and the potential for confounding bias. Conclusion: The results of a multiple database search draw one to the conclusion that there is very limited evidence in the literature with regard to prophylactic enoxaparin dosing in obese orthopedic-specific patients. Orthopedic patients are among the highest risk of all surgical specialties for venous thromboembolism. There is strong evidence to support an increased prophylactic low-molecular-weight heparin doses in obese patients; thus, the authors recommend higher prophylactic enoxaparin dosing in obese orthopedic patients.

The use of an activity tracker to objectively measure inpatient activity after bariatric surgery

BACKGROUND

Early postoperative ambulation reduces length of stay and prevents postoperative complications after bariatric surgery. Rarely is postoperative inpatient activity objectively measured despite readily available commercial activity trackers.

OBJECTIVES

Evaluate the impact of using activity trackers to record number of inpatient steps taken after bariatric surgery and assess how patient characteristics may affect the number of steps recorded.

SETTING

University Hospital, United States.

METHODS

Using an activity tracker, the number of steps taken during the postoperative hospital stay was recorded for 235 patients undergoing either laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy. Patients were randomly assigned to either being informed about the devices' ability to record the number of steps taken or blinded to the purpose of the devices. Descriptive statistics were used to summarize study sample, a t test was used to compare number of steps recorded between groups, and a multivariate regression model was used to examine the effect of age, sex, preoperative body mass index (BMI), types of surgery, and length of stay on number of steps recorded.

RESULTS

One hundred twenty-five patients (52.8%) were randomized to the blinded group while 111 (47.2%) were informed that the device would record the number of steps taken. There were no differences in the number of steps recorded between the 2 groups. Patients with prolonged length of stay recorded lower numbers of steps taken on postoperative day 0. Increasing age was seen to reduce the number of steps recorded on postoperative day number 1. There were no significant differences in number of steps recorded based on sex, preoperative BMI, or surgery type.

CONCLUSION

The present study found that knowledge of an activity tracker being used did not affect the patient's activity level as measured by steps recorded. Increasing age correlated to reduced number of steps recorded on postoperative day 1 after bariatric surgery.

Perioperative morbidity in total knee arthroplasty

Introduction

As the life expectancy and weight of patients are increasing, more old and obese patients are undergoing total knee arthroplasty (TKA). TKA may lead to several perioperative complications. These include anesthesia-related risks, exacerbation of comorbid medical issues and complications of surgical procedure. We have no studies reporting medical complications following TKA among our population. This study aimed to evaluate perioperative complications of TKA and to identify the related risk factors.

Methods

It was a monocentric retrospective including 410 observations in the local TKA registry. Data of patients operated for primary unilateral TKA during the period from January 2014 to December 2017 were reviewed. All patients had standardized protocols of anesthesia and post operative care for three days following surgery. Multivariate logistic regression was used to identify the predicting factors for complications.

Results

Incidence of perioperative complications was 37.1%. The most frequent were per operative hypotension (14.1%) and postoperative desaturation (21.7%, including pulmonary embolism in 2.4%). Multivariate logistic regression analysis identified: age ≥ 65 years (OR=1.9; p=0.006), respiratory diseases (OR=1.8; p=0.042) and general anesthesia (OR=2.8; p=0.009) as significant risk factors for any complications. Loss of autonomy (OR=4.8; p <0.001) and general anesthesia (OR=2.6; p=0.03) were significant risk factors for hypotension. Age ≥ 65 years (OR=2.6;p<0.001), female gender (OR=4.3;p=0.006) and respiratory diseases(OR=1.9;p=0.02) were associated with postoperative desaturation.

Conclusion

This study highlighted hemodynamic and respiratory complications as the most common early complications in TKA. Age ≥ 65years, general anesthesia and respiratory diseases were significant risk factors.

A quality improvement project decreases incidence of pulmonary embolism following arthroplasty

Objective

To develop a quality improvement initiative to reduce the incidence of pulmonary embolism (PE) following elective lower extremity joint replacement surgery.

Methods

866 Patients undergoing a total knee or total or partial hip replacement surgery at a from 2014 to 2016 were included in this prospective pre-post interventional study.

Results

There were 13 PE's before the intervention and 2 after the intervention. The incidence of PE was significantly higher prior to the intervention (2.8% vs. 0.7%; p = 0.044).

Conclusions

Our results suggest that our bundle of interventions was successfully implemented and helped to reduce the incidence of pulmonary embolism following surgery.

Venous Thromboembolism Quality Measures Fail to Accurately Measure Quality

Venous thromboembolism (VTE) is 1 of the most common causes of preventable harm for patients in hospitals. Consequently, the Joint Commission, the Centers for Medicare and Medicaid Services, the Agency for Healthcare Research and Quality, the United Kingdom Care Quality Commission, the Australian Commission on Safety and Quality in Health Care, the Maryland Health Services Cost Review Commission, and the American College of Surgeons have prioritized measuring and reporting VTE outcomes with the goal of reducing the incidence of and preventable harm from VTE. We developed a rubric for defect-free VTE prevention, graded each organizational VTE quality measure, and found that none of the current VTE-related quality measures adequately characterizes VTE prevention efforts or outcomes in hospitalized patients. Effective VTE prevention is multifactorial: clinicians must assess patients’ risk for VTE and prescribe therapy appropriate for each patient’s risk profile, patients must accept the prescribed therapy, and nurses must administer the therapy as prescribed. First, an ideal, defect-free VTE prevention process measure requires: (1) documentation of a standardized VTE risk assessment; (2) prescription of optimal, risk-appropriate VTE prophylaxis; and (3) administration of all risk-appropriate VTE prophylaxis as prescribed. Second, an ideal VTE outcome measure should define potentially preventable VTE as VTE that developed in patients who experienced any VTE prevention process failures.

Effect of joint mobilization techniques for primary total knee arthroplasty: Study protocol for a randomized controlled trial

BACKGROUND

Total knee arthroplasty (TKA) has become the most preferred procedure by patients for the relief of pain caused by knee osteoarthritis. TKA patients aim a speedy recovery after the surgery. Joint mobilization techniques for rehabilitation have been widely used to relieve pain and improve joint mobility. However, relevant randomized controlled trials showing the curative effect of these techniques remain lacking to date. Accordingly, this study aims to investigate whether joint mobilization techniques are valid for primary TKA.

METHODS/DESIGN

We will manage a single-blind, prospective, randomized, controlled trial of 120 patients with unilateral TKA. Patients will be randomized into an intervention group, a physical modality therapy group, and a usual care group. The intervention group will undergo joint mobilization manipulation treatment once a day and regular training twice a day for a month. The physical modality therapy group will undergo physical therapy once a day and regular training twice a day for a month. The usual care group will perform regular training twice a day for a month. Primary outcome measures will be based on the visual analog scale, the knee joint Hospital for Special Surgery score, range of motion, surrounded degree, and adverse effect. Secondary indicators will include manual muscle testing, 36-Item Short Form Health Survey, Berg Balance Scale function evaluation, Pittsburgh Sleep Quality Index, proprioception, and muscle morphology. We will direct intention-to-treat analysis if a subject withdraws from the trial.

DISCUSSION

The important features of this trial for joint mobilization techniques in primary TKA are randomization procedures, single-blind, large sample size, and standardized protocol. This study aims to investigate whether joint mobilization techniques are effective for early TKA patients. The result of this study may serve as a guide for TKA patients, medical personnel, and healthcare decision makers.

TRIAL REGISTRATION

It has been registered at http://www.chictr.org.cn/showproj.aspx?proj=15262 (Identifier:ChiCTR-IOR-16009192), Registered 11 September 2016. We also could provide the correct URL of the online registry in the WHO Trial Registration. http://apps.who.int/trialsearch/Trial2.aspx?TrialID=ChiCTR-IOR-16009192.

Obesity and Venous Thromboembolism in Total Knee Arthroplasty Patients in an Asian Population

BACKGROUND

Venous thromboembolism (VTE) is a known complication of total knee arthroplasty (TKA). In addition, obesity has been implicated as a risk factor and justification for chemoprophylaxis for VTE. We wanted to review the prevalence of VTE among our patients and evaluate the incidence rates of VTE among nonobese and obese patients.

METHODS

We reviewed 894 patients who underwent elective unilateral total knee arthroplasty by a single surgeon from March 2003 to November 2014 in our center. Any patients with clinically significant symptoms or signs of VTE such as deep venous thrombosis (DVT) or pulmonary embolism (PE) were diagnosed radiologically. The patient demographics analyzed included age, gender, body mass index, the number of comorbid diseases, and a history of hyperlipidemia.

RESULTS

We found the incidence of VTE of 0.67% in our patients (6 patients of 894). Four of the 6 patients (66.7%) who developed DVT and PE belonged to nonobese group. The frequency of VTE in nonobese patients was 0.65% and 0.73% in the obese patients. There were no significant differences in age, number of comorbidities, and a history of hyperlipidemia between those who developed DVT and PE and those who did not.

CONCLUSION

With the low prevalence of VTE among our study population, including patients with obesity, advanced age, multiple comorbidities, or hyperlipidemia, the practice of routine chemoprophylaxis should be reviewed.

Development of a Novel Composite Process Measure for Venous Thromboembolism Prophylaxis

BACKGROUND

Postoperative venous thromboembolism (VTE) is important clinically, and VTE quality metrics are used in public reporting and pay-for-performance programs. However, current VTE outcome measures are not valid due to surveillance bias, and the Surgical Care Improvement Project (SCIP-VTE-2) process measure only requires prophylaxis within 24 hours of surgery.

OBJECTIVES

We sought to (1) develop a novel measure of VTE prophylaxis that requires early ambulation, mechanical prophylaxis, and chemoprophylaxis throughout the hospitalization, and (2) compare hospital performance on the SCIP-VTE-2 process measure to this novel measure.

RESEARCH DESIGN

A new composite measure of ambulation, sequential compression device (SCD), and chemoprophylaxis component measures was developed. The ambulation component required daily ambulation, the SCD component required documentation of continuous use, and the chemoprophylaxis component required patient-appropriate and medication-appropriate dosing and administration. Requirements could also be met with component-specific exceptions. Surgical patients at an academic center from 2012 to 2013 were assessed for SCIP-VTE-2 and composite measure adherence.

RESULTS

Of 786 patients, 589 (74.9%) passed the ambulation measure, 494 (62.8%) passed the SCD measure, and 678 (86.3%) passed the chemoprophylaxis measure. A total of 268 (91.8%) SCD failures and 46 (42.6%) chemoprophylaxis failures were ordered but not administered. When comparing the 2 measures, 784 (99.7%) passed SCIP-VTE-2, whereas only 364 (46.3%) passed the composite measure (P<0.001).

CONCLUSIONS

This new measure incorporates the critical aspects of VTE prevention to ensure defect-free care. After additional evaluation, this composite VTE prophylaxis measure with appropriate exclusion criteria may be a better alternative to existing VTE process and outcome measures.

Obesity, orthopaedics, and outcomes

Obesity, one of the most common health conditions, affects an ever-increasing percentage of orthopaedic patients. Obesity is also associated with other medical conditions, including diabetes, cardiovascular disease, pulmonary disease, metabolic syndrome, and obstructive sleep apnea. These comorbidities require specific preoperative and postoperative measures to improve outcomes in this patient population. Patients who are obese are at risk for increased perioperative complications; however, orthopaedic procedures may still offer notable pain relief and improved quality of life.