Racial and Ethnic Minorities Underrepresented in Pain Management Guidelines for Total Joint Arthroplasty: A Meta-analysis.

BACKGROUND: Total joint arthroplasty aims to improve quality of life and functional outcomes for all patients, primarily by reducing their pain. This goal requires clinical practice guidelines (CPGs) that equitably represent and enroll patients from all racial/ethnic groups. To our knowledge, there has been no formal evaluation of the racial/ethnic composition of the patient population in the studies that informed the leading CPGs on the topic of pain management after arthroplasty surgery. QUESTIONS/PURPOSES: Using papers included in the 2021 Anesthesia and Analgesia in Total Joint Arthroplasty Clinical Practice Guidelines and comparing them with US National census data, we asked: (1) What is the representation of racial/ethnic groups in randomized controlled trials compared with their representation in the US national population? (2) Is there a relationship between the reporting of racial/ethnic groups and year of data collection/publication, location of study, funding source, or guideline section? METHODS: Participant demographic data (study year published, study type, guideline section, year of data collection, study site, study funding, study size, gender, age, and race/ethnicity) were collected from articles cited by this guideline. Studies were included if they were full text, were primary research articles conducted primarily within the United States, and if they reported racial and ethnic characteristics of the participants. The exclusion criteria included duplicate articles, articles that included the same participant population (only the latest dated article was included), and the following article types: systematic reviews, nonsystematic reviews, terminology reports, professional guidelines, expert opinions, population-based studies, surgical trials, retrospective cohort observational studies, prospective cohort observational studies, cost-effectiveness studies, and meta-analyses. Eighty-two percent (223 of 271) of articles met inclusion criteria. Our original literature search yielded 27 papers reporting the race/ethnicity of participants, including 24 US-based studies and three studies conducted in other countries; only US-based studies were utilized as the focus of this study. We defined race/ethnicity reporting as the listing of participants' race or ethnicity in the body, tables, figures, or supplemental data of a study. National census information from 2000 to 2019 was then used to generate a representation quotient (RQ), which compared the representation of racial/ethnic groups within study populations to their respective demographic representation in the national population. An RQ value greater than 1 indicates an overrepresented group and an RQ value less than 1 indicates an underrepresented group, relative to the US population. Primary outcome measures of RQ value versus time of publication for each racial/ethnic group were evaluated with linear regression analysis, and race reporting and manuscript parameters were analyzed with chi-square analyses. RESULTS: Two US-based studies reported race and ethnicity independently. Among the 24 US-based studies reporting race/ethnicity, the overall RQ was 0.70 for Black participants, 0.09 for Hispanic participants, 0.1 for American Indian/Alaska Natives, 0 for Native Hawaiian/Pacific Islanders, 0.08 for Asian participants, and 1.37 for White participants, meaning White participants were overrepresented by 37%, Black participants were underrepresented by 30%, Hispanic participants were underrepresented by 91%, Asian participants were underrepresented by 92%, American Indian/Alaska Natives were 90% underrepresented, and Native Hawaiian Pacific Islanders were virtually not represented compared with the US national population. On chi-square analysis, there were differences between race/ethnicity reporting among studies with academic, industry, and dual-supported funding sources (χ2 = 7.449; p = 0.02). Differences were also found between race/ethnicity reporting among US-based and non-US-based studies (χ2 = 36.506; p < 0.001), with 93% (25 of 27) of US-based studies reporting race as opposed to only 7% (2 of 27) of non-US-based studies. Finally, there was no relationship between race/ethnicity reporting and the year of data collection or guideline section referenced. CONCLUSION: The 2021 Anesthesia and Analgesia in Total Joint Arthroplasty Clinical Practice Guidelines provide evidence-based recommendations that reflect the current standards in orthopaedic surgery, but the studies upon which they are based overwhelmingly underenroll and underreport racial/ethnic minorities relative to their proportions in the US population. As these factors impact analgesic administration, their continued neglect may perpetuate inequities in outcomes after TJA. CLINICAL RELEVANCE: Our study demonstrates that all non-White racial/ethnic groups were underrepresented relative to their proportion of the US population in the 2021 Anesthesia and Analgesia in Total Joint Arthroplasty Clinical Practice Guidelines, underscoring a weakness in the orthopaedic surgery evidence base and questioning the overall external validity and generalizability of these combined CPGs. An effort should be made to equitably enroll and report outcomes for all racial/ethnic groups in any updated CPGs.

Quantifying Patient Expectations for Total Knee Arthroplasty: Expectations for Improvement Are Greater Than Minimal Clinically Important Difference.

BACKGROUND: Achieving a minimal clinically important difference (MCID) in patient-reported outcomes following total knee arthroplasty (TKA) is common, yet up to 20% patient dissatisfaction persists. Unmet expectations may explain post-TKA dissatisfaction. No prior studies have quantified patient expectations using the same patient-reported outcome metric as used for MCID to allow direct comparison. METHODS: This was a prospective study of patients undergoing TKA with 5 fellowship-trained arthroplasty surgeons at one academic center. Baseline Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) and Pain Interference (PI) domains were assessed. Expected PROMIS scores were determined by asking patients to indicate the outcomes they were expecting at 12 months postoperatively. Predicted scores were generated from a predictive model validated in the Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement (FORCE-TJR) dataset. T-tests were used to compare baseline, expected, and predicted PROMIS scores. Expected scores were compared to PROMIS MCID values obtained from the literature. Regression models were used to identify patient characteristics associated with high expectations. RESULTS: There were 93 patients included. Mean age was 67 years (range, 30 to 85) and 55% were women. Mean baseline PROMIS PF and PI was 34.4 ± 6.7 and 62.2 ± 6.4, respectively. Patients expected significant improvement for PF of 1.9 times the MCID (MCID = 11.3; mean expected improvement = 21.6, 95% confidence interval [CI] 19.6 to 23.5, P < .001) and for PI of 2.3 times the MCID (MCID = 8.9; mean expected improvement = 20.6, 95% CI 19.1-22.2, P < .001). Predicted scores were significantly lower than expected scores (mean difference = 9.5, 95% CI 7.7 to 11.3, P < .001). No unique patient characteristics were associated with high expectations (P > .05). CONCLUSIONS: To our knowledge, this study is the first to quantify preoperative patient expectations using the same metric as MCID to allow for direct comparison. Patient expectations for improvement following TKA are ∼2× greater than MCID and are significantly greater than predicted outcome scores. This discrepancy challenges currently accepted standards of success after TKA and indicates a need for improved expectation setting prior to surgery.

Association Between Nonsurgical Weight Loss From Body Mass Index >40 to Body Mass Index <40 and Complications and Readmissions Following Total Hip Arthroplasty.

BACKGROUND: Elevated body mass index (BMI) is a risk factor for adverse outcomes following total hip arthroplasty (THA). It is unknown if preoperative weight loss to a BMI <40 kg/m2 is associated with reduced risk of adverse outcomes. METHODS: We retrospectively reviewed elective, primary THA performed at an academic center from 2015 to 2019. Patients were split into groups based on their BMI trajectory prior to THA: BMI consistently <40 ("BMI <40"); BMI >40 at the time of surgery ("BMI >40"); and BMI >40 within 2 years preoperatively, but <40 at the time of surgery ("Weight Loss"). Length of stay (LOS), 30-day readmissions, and complications as defined by Centers for Medicare and Medicaid Services were compared between groups using parsimonious regression models and Fisher's exact testing. Adjusted analyses controlled for sex, age, and American Society of Anesthesiologists class. RESULTS: In total, 1589 patients were included (BMI <40: 1387, BMI >40: 96, Weight Loss: 106). The rate of complications in each group was 3.5%, 6.3%, and 8.5% and the rate of 30-day readmissions was 3.0%, 4.2%, and 7.5%, respectively. Compared to the BMI <40 group, the weight loss group had a significantly higher risk of 30-day readmission (odds ratio [OR] 2.70, 95% confidence interval [CI] 1.19-6.17, P = .02), higher risk of any complication (OR 2.47, 95% CI 1.09-5.59, P = .03), higher risk of mechanical complications (OR 3.07, 95% CI 1.14-8.25, P = .03), and longer median LOS (16% increase, P = .002). The BMI >40 group had increased median LOS (10% increase, P = .03), but no difference in readmission or complications (P > .05) compared to BMI <40. CONCLUSION: Weight loss from BMI >40 to BMI <40 prior to THA was associated with increased risk of readmission and complications compared to BMI <40, whereas BMI >40 was not. LEVEL OF EVIDENCE: Level III - Retrospective Cohort Study.

Do In-Hospital Rothman Index Scores Predict Postdischarge Adverse Events and Discharge Location After Total Knee Arthroplasty?

BACKGROUND: There have been efforts to reduce adverse events and unplanned readmissions after total joint arthroplasty. The Rothman Index (RI) is a real-time, composite measure of medical acuity for hospitalized patients. We aimed to examine the association among in-hospital RI scores and complications, readmissions, and discharge location after total knee arthroplasty (TKA). We hypothesized that RI scores could be used to predict the outcomes of interest. METHODS: This is a retrospective study of an institutional database of elective, primary TKA from July 2018 until December 2019. Complications and readmissions were defined per Centers for Medicare and Medicaid Services. Analysis included multivariate regression, computation of the area under the curve (AUC), and the Youden Index to set RI thresholds. RESULTS: The study cohort's (n = 957) complications (2.4%), readmissions (3.6%), and nonhome discharge (13.7%) were reported. All RI metrics (minimum, maximum, last, mean, range, 25th%, and 75th%) were significantly associated with increased odds of readmission and home discharge (all P < .05). RI scores were not significantly associated with complications. The optimal RI thresholds for increased risk of readmission were last ≤ 71 (AUC = 0.65), mean ≤ 67 (AUC = 0.66), or maximum ≤ 80 (AUC = 0.63). The optimal RI thresholds for increased risk of home discharge were minimum ≥ 53 (AUC = 0.65), mean ≥ 69 (AUC = 0.65), or maximum ≥ 81 (AUC = 0.60). CONCLUSION: RI values may be used to predict readmission or home discharge after TKA.

The Impact of Pre-Operative Healthcare Utilization on Complications, Readmissions, and Post-Operative Healthcare Utilization Following Total Joint Arthroplasty.

BACKGROUND: Identifying risk factors for adverse outcomes and increased costs following total joint arthroplasty (TJA) is needed to ensure quality. The interaction between pre-operative healthcare utilization (pre-HU) and outcomes following TJA has not been fully characterized. METHODS: This is a retrospective cohort study of patients undergoing elective, primary total hip arthroplasty (THA, N = 1785) or total knee arthroplasty (TKA, N = 2159) between 2015 and 2019 at a single institution. Pre-HU and post-operative healthcare utilization (post-HU) included non-elective healthcare utilization in the 90 days prior to and following TJA, respectively (emergency department, urgent care, observation admission, inpatient admission). Multivariate regression models including age, gender, American Society of Anesthesiologists, Medicaid status, and body mass index were fit for 30-day readmission, Centers for Medicare and Medicaid services (CMS)-defined complications, length of stay, and post-HU. RESULTS: The 30-day readmission rate was 3.2% and 3.4% and the CMS-defined complication rate was 3.8% and 2.9% for THA and TKA, respectively. Multivariate regression showed that for THA, presence of any pre-HU was associated with increased risk of 30-day readmission (odds ratio [OR] 2.85, 95% confidence interval [CI] 1.48-5.50, P = .002), CMS complications (OR 2.42, 95% CI 1.27-4.59, P = .007), and post-HU (OR 3.65, 95% CI 2.54-5.26, P < .001). For TKA, ≥2 pre-HU events were associated with increased risk of 30-day readmission (OR 3.52, 95% CI 1.17-10.61, P = .026) and post-HU (OR 2.64, 95% CI 1.29-5.40, P = .008). There were positive correlations for THA (any pre-HU) and TKA (≥2 pre-HU) with length of stay and number of post-HU events. CONCLUSION: Patients who utilize non-elective healthcare in the 90 days prior to TJA are at increased risk of readmission, complications, and unplanned post-HU. LEVEL OF EVIDENCE: Level III.

What Mid-term Patient-reported Outcome Measure Scores, Reoperations, and Complications Are Associated with Concurrent Hip Arthroscopy and Periacetabular Osteotomy to Treat Dysplasia with Associated Intraarticular Abnormalities?

BACKGROUND: Periacetabular osteotomy (PAO) is a well-accepted treatment for acetabular dysplasia, but treatment success is not uniform. Concurrent hip arthroscopy has been proposed for select patients to address intraarticular abnormalities. The patient-reported outcomes, complications, and reoperations for concurrent arthroscopy and PAO to treat acetabular dysplasia remain unclear. QUESTIONS/PURPOSES: (1) What are the functional outcome scores among select patients treated with PAO plus concurrent hip arthroscopy at mid-term follow-up? (2) What factors are associated with conversion to THA or persistent symptoms (modified Harris hip score ≤ 70 or WOMAC pain subscore ≥ 10)? (3) What proportion of patients underwent further hip preservation surgery at mid-term follow-up? (4) What are the complications associated with the procedure? METHODS: Between November 2005 and December 2012, 78 patients (81 hips) who presented with symptomatic acetabular dysplasia-defined as a lateral center-edge angle less than 20° with hip pain for more than 3 months that interfered with daily function-had undergone unsuccessful nonsurgical treatment, had associated intraarticular abnormalities on MRI, and underwent combined hip arthroscopy and PAO. Eleven patients did not have minimum 4-year follow-up and were excluded, leaving 67 patients (70 hips) who met our inclusion criteria and had a mean follow-up duration of 6.5 ± 1.6 years. We retrospectively evaluated patient-reported outcomes at final follow-up using the University of California Los Angeles (UCLA) activity score, the modified Harris Hip Score (mHHS), and the WOMAC pain subscore. Conversion to THA or persistent symptoms were considered clinical endpoints. Repeat surgical procedures were drawn from a prospectively maintained database, and major complications were graded according to the validated Clavien-Dindo classification (Grade III or IV). Student t-tests, chi-square tests, and Fisher exact tests identified the association of patient factors, radiographic measures, and surgical details with clinical endpoints. For patients who underwent bilateral procedures, only the first hip was included in our analyses. RESULTS: At final follow-up, the mean mHHS for all patients improved from a mean ± SD of 55 ± 19 points to 85 ± 17 points (p < 0.001), the UCLA activity score improved from 6.5 ± 2.7 points to 7.5 ± 2.2 points (p = 0.01), and the WOMAC pain score improved from 9.1 ± 4.3 points to 3.2 ± 3.9 points (p < 0.001). Three percent (2 of 67) of patients underwent subsequent THA, while 21% (15 of 70) of hips were persistently symptomatic, defined as mHHS less than or equal to 70 or WOMAC pain subscore greater than or equal to 10. Univariate analyses indicated that no patient demographics, preoperative or postoperative radiographic metrics, or intraoperative findings or procedures were associated with subsequent THA or symptomatic hips. Worse baseline mHHS and WOMAC pain scores were associated with subsequent THA or symptomatic hips. Seven percent (5 of 67) of patients underwent repeat hip preservation surgery for recurrent symptoms, and 4% (3 of 67) of patients had major complications (Clavien-Dindo Grade III or IV). CONCLUSION: This study demonstrated that concurrent hip arthroscopy and PAO to treat symptomatic acetabular dysplasia (with intraarticular abnormalities) has good clinical outcomes at mid-term follow-up in many patients; however, persistent symptoms or conversion to THA affected almost a quarter of the sample. We noted an acceptable complication profile. Further study is needed to directly compare this approach to more traditional techniques that do not involve arthroscopy. We do not use isolated hip arthroscopy to treat symptomatic acetabular dysplasia. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Assessment of Psychological Factors in Short-Stay Total Hip Arthroplasty Protocol.

BACKGROUND: Several variables are known to correlate with the successful completion of short-stay total hip arthroplasty (THA) protocols. The role of psychological factors remains unclear. We investigated the interaction between patient-reported measures of psychological fitness and successful completion of a short-stay THA protocol. METHODS: We performed a prospective cohort study of patients undergoing elective anterior total hip arthroplasty enrolled in a short-stay protocol (success defined as LOS ≤1 midnight versus failed, LOS >1 midnight). Psychological fitness was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) domains for self-efficacy, depression, anxiety, emotional support, and the ability to participate in social roles. PROMIS scores, patient demographics, and surgical factors were assessed for a relationship with failure to complete short-stay protocol. RESULTS: Patients that failed to complete the short-stay protocol had higher mean pre-operative PROMIS depression scores (50.8 vs 47.1, P = .025) and anxiety scores (53.6 vs 49.2, P = .008) and higher postoperative PROMIS depression (48.19 vs 43.49, P = .003) and anxiety scores (51.7 vs 47.1, P = .01). Demographic and surgical variables did not correlate with the successful completion of the short-stay protocol. That seventy-six percent of the patients did not adhere to the short-stay protocol was due to the inability to complete a physical therapy standardized safety assessment. CONCLUSION: Higher levels of preoperative and postoperative anxiety and depression in otherwise psychologically healthy patients, is associated with an increased risk of failure to complete a short-stay protocol following THA. Targeted interventions are needed to facilitate rapid recovery in patients with psychological barriers to early mobilization.

Choices, Compromises, and Controversies in Total Knee Arthroplasty.

Although condylar total knee arthroplasty (TKA) has been performed for almost 40 years, many choices, compromises, and controversies remain. In the effort to provide optimal care and beneficial, enduring treatment for an expanding population of patients with debilitating arthritis of the knee and who are using ever-diminishing provider and financial resources, orthopaedic surgeons must carefully examine the available evidence to determine best practices. First, there is debate as to who should be a candidate for TKA. Beyond the established criteria of disease severity, should all patients who can benefit from TKA undergo the procedure, or should surgeons develop exclusion criteria based on complication risk? Current concepts for identifying and managing modifiable risk factors should be considered. Second, there is debate regarding the choice of TKA versus partial knee arthroplasty to manage unicompartmental arthritis. Third, surgeons continue to debate the ideal implant design for primary condylar TKA, whether to proceed with an anatomic approach of preserving one or both cruciate ligaments or a functional approach of resecting and substituting for the cruciate ligaments in various ways.

Statistical Methods Dictate the Estimated Impact of Body Mass Index on Major and Minor Complications After Total Joint Arthroplasty.

BACKGROUND: Elevated body mass index (BMI) is considered a risk factor for complications after THA and TKA. Stakeholders have proposed BMI cutoffs for those seeking arthroplasty. The research that might substantiate BMI cutoffs is sensitive to the statistical methods used, but the impact of the statistical methods used to model BMI has not been defined. QUESTIONS/PURPOSES: (1) How does the estimated postarthroplasty risk of minor and major complications vary as a function of the statistical method used to model BMI? (2) What is the prognostic value of BMI for predicting complications with each statistical method? METHODS: Using the American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2012, we investigated the impact of BMI on major and minor complication risk for THA and TKA. Analyses were weighted with covariate-balancing propensity scores to account for the differential rate of comorbidities across the range of BMI. We specified BMI in two ways: (1) categorically by World Health Organization (WHO) BMI classes; and (2) as a smooth, continuous variable using splines. Models of risk for major complications (deep surgical site infection [SSI], pulmonary embolism, stroke, cardiac arrest, myocardial infarction, wound disruption, implant failure, unplanned intubation, > 48 hours on a ventilator, acute renal insufficiency, coma, sepsis, reoperation, or mortality) and minor complications (superficial SSI, pneumonia, urinary tract infection, deep vein thrombosis, or peripheral nerve injury) were constructed and were adjusted for confounding variables known to correlate with complications (eg, American Society of Anesthesiologists classification). Results were compared for different specifications of BMI. Receiver operating characteristic (ROC) curves were compared to determine the additive prognostic value of BMI. RESULTS: The type of BMI parameterization leads to different assessments of risk of postarthroplasty complications for BMIs > 30 kg/m and < 20 kg/m with the spline specification showing better fit in all adjusted models (Akaike Information Criteria favors spline). Modeling BMI categorically using WHO classes indicates that BMI cut points of 40 kg/m for TKA or 35 kg/m for THA are associated with higher risks of major complications. Modeling BMI continuously as a spline suggests that risk of major complications is elevated at a cut point of 44 kg/m for TKA and 35 kg/m for THA. Additionally, in these models, risk does not uniformly increase with increasing BMI. Regardless of the method of modeling, BMI is a poor prognosticator for complications with area under the ROC curves between 0.51 and 0.56, false-positive rates of 96% to 97%, and false-negative rates of 2% to 3%. CONCLUSIONS: The statistical assumptions made when modeling the effect of BMI on postarthroplasty complications dictate the results. Simple categorical handling of BMI creates arbitrary cutoff points that should not be used to inform larger policy decisions. Spline modeling of BMI avoids arbitrary cut points and provides a better model fit at extremes of BMI. Regardless of statistical management, BMI is an inadequate independent prognosticator of risk for individual patients considering total joint arthroplasty. Stakeholders should instead perform comprehensive risk assessment and avoid use of BMI as an isolated indicator of risk. LEVEL OF EVIDENCE: Level III, diagnostic study.

Systemic Absorption of Antibiotics From Antibiotic-Loaded Cement Spacers for the Treatment of Periprosthetic Joint Infection.

BACKGROUND: Two-stage treatment of periprosthetic joint infections involves placement of high-dose antibiotic-loaded cement spacers (ACSs). Reports of ACS-induced nephrotoxicity have raised concern regarding systemic absorption of antibiotics after ACS placement. We sought to characterize the serum concentrations of antibiotics that occur after ACS placement. METHODS: We performed a prospective study of patients with an infected primary total hip (THA) or knee arthroplasty (TKA) treated with standardized ACSs with vancomycin, gentamicin, and tobramycin. Serum antibiotic levels were collected weekly for 8 weeks. RESULTS: Twenty-one patients (10 THA, 11 TKA) were included. Mean serum gentamicin levels ranged between 0.275±0.046 and 0.364±0.163 mg/L; mean serum tobramycin levels ranged from 0.313±0.207 to 0.527±0.424 mg/L; and mean serum vancomycin levels ranged from 5.46±6.6 to 15.34±9.6 mg/L. Serum antibiotic levels were detectable throughout the 8-week duration of ACS treatment. Regression analysis found that diabetes (coefficient 6.73, 95% CI 0.92-12.54, P < .05), blood urea nitrogen (coefficient 0.83, 95% CI 0.45-1.22, P < .001), number of cement doses (coefficient 3.71, 95% CI 0.76-6.66, P < .05), and use of systemic vancomycin (coefficient 6.24, 95% CI 2.72-9.75, P < .001) correlated with serum vancomycin levels. Patient age (coefficient -0.01, 95% CI -0.02 to 0, P < .01) and male sex (coefficient 0.20, 95% CI 0-0.41, P < .05) correlated with serum aminoglycoside level. CONCLUSION: Systemic absorption of antibiotics from high-dose ACS persists for at least 8 weeks. Patients should be monitored closely for complications related to systemic absorption of antibiotics from ACS treatment.

Nephrotoxicity After the Treatment of Periprosthetic Joint Infection With Antibiotic-Loaded Cement Spacers.

BACKGROUND: Treatment of periprosthetic joint infections commonly involves insertion of an antibiotic-loaded cement spacer (ACS). The risk for acute kidney injury (AKI) related to use of antibiotic spacers has not been well defined. We aimed to identify the incidence of and risk factors for AKI after placement of an ACS. METHODS: We performed a prospective cohort study of patients with an infected primary total hip or knee arthroplasty treated with ACSs with vancomycin, gentamicin, and tobramycin. Serum creatinine and glomerular filtration rate data were collected at baseline and weekly intervals for 8 weeks. Patients were classified into Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) stages to determine incidence of AKI. Risk factors for kidney injury were identified via regression analysis. RESULTS: A total of 37 patients (20 total knee arthroplasty and 17 total hip arthroplasty) were included. During the 8 weeks after ACS placement, 10 patients (27%) fit RIFLE criteria for kidney injury and 2 patients (5%) fit RIFLE criteria for kidney failure. No baseline patient characteristics were associated with development of AKI. CONCLUSION: Patients should be monitored closely for development of AKI after placement of ACSs for the treatment of periprosthetic joint infection. Further research into minimizing risk for AKI is warranted.

The Impact of Metabolic Syndrome on 30-Day Complications Following Total Joint Arthroplasty.

BACKGROUND: The arthroplasty population increasingly presents with comorbid conditions linked to elevated risk of postsurgical complications. Current quality improvement initiatives require providers to more accurately assess and manage risk presurgically. In this investigation, we assess the effect of metabolic syndrome (MetS), as well as the effect of body mass index (BMI) within MetS, on the risk of complication following hip and knee arthroplasty. METHODS: We queried the American College of Surgeons National Surgical Quality Improvement Program database for total hip or knee arthroplasty cases. Thirty-day rates of Centers for Medicare and Medicaid Services (CMS)-reportable complications, wound complications, and readmissions were compared between patients with and without a diagnosis of MetS using multivariate logistic regression. Arthroplasty cases with a diagnosis of MetS were further stratified according to World Health Organization BMI class, and the role of BMI within the context of MetS was assessed. RESULTS: Of the 107,117 included patients, 11,030 (10.3%) had MetS. MetS was significantly associated with CMS complications (odds ratio [OR] = 1.415; 95% confidence interval [CI], 1.306-1.533; P < .001), wound complications (OR = 1.749; 95% CI, 1.482-2.064; P < .001), and readmission (OR = 1.451; 95% CI, 1.314-1.602; P < .001). When MetS was assessed by individual BMI class, the MetS + BMI >40 group was associated with significantly higher risk of CMS complications, wound complications, and readmission compared to the lower MetS BMI groups. CONCLUSION: MetS is an independent risk factor for CMS-reportable complications, wound complications, and readmission following total joint arthroplasty. The risk attributable to MetS exists irrespective of obesity class and increases as BMI increases.

The Interaction of Obesity and Metabolic Syndrome in Determining Risk of Complication Following Total Joint Arthroplasty.

BACKGROUND: The arthroplasty population is increasingly comorbid, and current quality improvement initiatives demand accurate risk stratification. Metabolic syndrome (MetS) has been identified as a risk factor for adverse events after arthroplasty; however, its interaction with obesity in contributing to risk is unclear. METHODS: A retrospective analysis of all Medicare patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at a single institution from 2009 to 2013 investigated the interaction between MetS, body mass index (BMI), and risk for Centers for Medicare and Medicaid Services (CMS)-reportable complications, readmission, and discharge disposition. RESULTS: A total of 1462 patients (942 TKA, 538 THA) were included, of which 16.2% had MetS. Regression analysis found that MetS was significantly related to risk of CMS complications (odds ratio [OR] = 1.96, 95% confidence interval [CI] 1.16-3.31, P = .012) and nonhome discharge (OR = 1.78, 95% CI 1.39-2.27, P < .001), but not readmission (OR = 1.23, 95% CI 0.7-2.18, P = .485). Within the MetS cohort, increasing BMI was not associated with increasing complications (P = .726) or readmissions (P = .206) but was associated with nonhome discharge (OR = 1.191 per unit increase in BMI, 95% CI 1.038-1.246, P = .001). CONCLUSION: MetS increases risk for CMS-reportable complications and nonhome discharge disposition after THA and TKA regardless of BMI. Obesity is of less value than MetS in assessing overall risk for complication after THA and TKA.

Perioperative Outcomes Following Unilateral Versus Bilateral Total Knee Arthroplasty.

Simultaneous bilateral total knee arthroplasty (SB-TKA) is potentially a cost saving manner of caring for patients with bilateral symptomatic knee arthritis. We performed a retrospective analysis using the 2010-2012 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) to evaluate the risk of perioperative complication following SB-TKA. Demographic characteristics, comorbidities, and 30-day complication rates were studied using a propensity score-matched analysis comparing patients undergoing unilateral TKA and SB-TKA. A total of 4489 patients met the inclusion criteria, of which 973 were SB-TKA. SB-TKA was associated with increased overall complications (P = 0.023), medical complications (P = 0.002) and reoperation (OR 2.12, P = 0.020). Further, total length of hospital stay (4.0 vs 3.4 days, P < 0.001) was significantly longer following bilateral surgery.

Can the American College of Surgeons Risk Calculator Predict 30-Day Complications After Knee and Hip Arthroplasty?

Accurate risk stratification of patients undergoing total hip (THA) and knee (TKA) arthroplasty is essential in the highly scrutinized world of pay-for-performance, value-driven healthcare. We assessed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculator's ability to predict 30-day complications using 1066 publicly-reported Medicare patients undergoing primary THA or TKA. Risk estimates were significantly associated with complications in the categories of any complication (P = .005), cardiac complication (P < .001), pneumonia (P < .001) and discharge to skilled nursing facility (P < .001). However, predictability of complication occurrence was poor for all complications assessed. To facilitate the equitable provision and reimbursement of patient care, further research is needed to develop accurate risk stratification tools in TKA and THA surgery.

Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs.

BACKGROUND: The coronal plane alignment of the knee (CPAK) classification was first developed using long leg radiographs (LLR) and has since been reported using image-based and imageless robotic total knee arthroplasty (TKA) systems. However, the correspondence between imageless robotics and LLR-derived CPAK parameters has yet to be investigated. This study therefore examined the differences in CPAK parameters determined with LLR and imageless robotic navigation using either generic or optimized cartilage wear assumptions. METHODS: Medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA) were determined from the intraoperative registration data of 61 imageless robotic TKAs using either a generic 2 mm literature-based wear assumption (Navlit) or an optimized wear assumption (Navopt) found using an error minimization algorithm. MPTA and LDFA were also measured from preoperative LLR by two observers and intraclass correlation coefficients (ICCs) were calculated. MPTA, LDFA, joint line obliquity (JLO), and arithmetic hip-knee-ankle angle (aHKA) were compared between the robotic and the average LLR measurements over the two observers. RESULTS: ICCs between observers for LLR were over 0.95 for MPTA, LDFA, JLO, and aHKA, indicating excellent agreement. Mean CPAK differences were not significant between LLR and Navlit (all differences within 0.6°, P > 0.1) or Navopt (all within 0.1°, P > 0.83). Mean absolute errors (MAE) between LLR and Navlit were: LDFA = 1.4°, MPTA = 2.0°, JLO = 2.1°, and aHKA = 2.7°. Compared to LLR, the generic wear classified 88% and the optimized wear classified 94% of knees within one CPAK group. Bland-Altman comparisons reported good agreement for LLR vs. Navlit and Navopt, with > 95% and > 91.8% of measurements within the limits of agreement across all CPAK parameters, respectively. CONCLUSIONS: Imageless robotic navigation data can be used to calculate CPAK parameters for arthritic knees undergoing TKA with good agreement to LLR. Generic wear assumptions determined MPTA and LDFA with MAE within 2° and optimizing wear assumptions showed negligible improvement.

Agreement of the American Academy of Orthopaedic Surgeons Appropriate Use Criteria With Treatment Recommendations From Arthroplasty Surgeons.

Background: The American Academy of Orthopaedic Surgeons (AAOS) Appropriate Use Criteria (AUC) for Surgical Management of Osteoarthritis of the Knee (2016) and Management of Osteoarthritis of the Hip (2017) are intended to provide treatment recommendations for osteoarthritis (OA). This study examined the agreement of AUC appropriateness classifications with arthroplasty surgeon recommendations for total knee arthroplasty (TKA) and total hip arthroplasty (THA). Methods: The cohort included 558 OA patients (397 knee, 161 hip) referred to a specialty arthroplasty clinic. Surgeons completed the online AAOS AUC patient profiles to generate appropriateness ratings. Surgeons' recommendations for treatment were recorded. We performed univariate and bivariate analyses to evaluate relationships between AUC appropriateness and surgeon recommendations. Results: The knee OA AUC classified TKA as "appropriate" for 309 (77.8%) of the 397 knee OA patients. Surgeons recommended TKA for 123 (31.0%), resulting in 46.8% (n = 186) higher rate of "appropriate" classification by AUC than TKA recommendation by surgeons. Weighted Cohen's κ demonstrated slight agreement (κ = 0.06, 95% confidence interval: 0.04, 0.09) between AUC appropriateness and surgeon TKA recommendation. The hip OA AUC classified THA as "appropriate" for 98 (60.9%) of the 161 hip OA patients. Surgeons recommended THA for 76 (47.2%), resulting in 13.7% (n = 22) higher rate of "appropriate" classification by AUC than THA recommendation by surgeons. Weighted Cohen's κ demonstrated moderate agreement (κ = 0.47, 95% confidence interval: 0.37, 0.57) between the AUC appropriateness classification and the surgeon's THA recommendation. Conclusions: AAOS AUC guidelines indicated surgical appropriateness significantly more than arthroplasty surgeons. AUC agreed slightly with surgeons for TKA and moderately for THA.

Age-Based Heuristics Bias Treatment of Displaced Femoral Neck Fractures in the Elderly.

Background: Surgeons performing arthroplasty for femoral neck fractures may rely on mental shortcuts (heuristics) when choosing total hip arthroplasty (THA) vs hemiarthroplasty (HA). We sought to quantify the extent to which age-based heuristics drive decision-making. Methods: We identified all Medicare beneficiaries from 2017-2018 with femoral neck fractures who underwent THA or HA. We compared the likelihood of THA vs HA among patients admitted within 4 weeks before vs 4 weeks after their birthday for each age under the hypothesis that these cohorts would be similar except for numerical age. We controlled for race/ethnicity, sex, comorbidities, poverty status, and hospital census region in a multivariable regression that included facility-level cluster effects. We generated predicted/adjusted probabilities for THA vs HA for different age transition points. Results: Thirteen thousand three hundred sixty-six elderly patients were included. One thousand eight hundred sixty-five (14%) received THA and 11,501 (86%) received HA. The likelihood of THA decreased from 50.3% among patients almost 67 to 8% among those ≥85 (P < .001). We found significant decreases in likelihood of THA across age transitions. The largest decrement was at age transition 69 (THA likelihood 28.7% for newly 69 vs 43.3% for almost 69, 33.7% relative change). Female gender, Black race, higher comorbidity burden, and lower socioeconomic status were also associated with a lower likelihood of THA. Conclusions: Our data demonstrate that patient age transitions seem to influence the choice of THA vs HA. Further research is needed to develop data-driven surgical decision aids for this population.

The Role of the Gut Microbiome in Orthopedic Surgery-a Narrative Review.

PURPOSE OF REVIEW: The importance of the gut microbiome has received increasing attention in recent years. New literature has revealed significant associations between gut health and various orthopedic disorders, as well as the potential for interventions targeting the gut microbiome to prevent disease and improve musculoskeletal outcomes. We provide a broad overview of available literature discussing the links between the gut microbiome and pathogenesis and management of orthopedic disorders. RECENT FINDINGS: Human and animal models have characterized the associations between gut microbiome dysregulation and diseases of the joints, spine, nerves, and muscle, as well as the physiology of bone formation and fracture healing. Interventions such as probiotic supplementation and fecal transplant have shown some promise in ameliorating the symptoms or slowing the progression of these disorders. We aim to aid discussions regarding optimization of patient outcomes in the field of orthopedic surgery by providing a narrative review of the available evidence-based literature involving gut microbiome dysregulation and its effects on orthopedic disease. In general, we believe that the gut microbiome is a viable target for interventions that can augment current management models and lead to significantly improved outcomes for patients under the care of orthopedic surgeons.

Peptidoglycan in osteoarthritis synovial tissue is associated with joint inflammation.

OBJECTIVES: Peptidoglycan (PG) is an arthritogenic bacterial cell wall component whose role in human osteoarthritis is poorly understood. The purpose of this study was to determine if PG is present in synovial tissue of osteoarthritis patients at the time of primary total knee arthroplasty (TKA), and if its presence is associated with inflammation and patient reported outcomes. METHODS: Intraoperative synovial tissue and synovial fluid samples were obtained from 56 patients undergoing primary TKA, none of whom had history of infection. PG in synovial tissue was detected by immunohistochemistry (IHC) and immunofluorescence microscopy (IFM). Synovial tissue inflammation and fibrosis were assessed by histopathology and synovial fluid cytokine quantification. Primary human fibroblasts isolated from arthritis synovial tissue were stimulated with PG to determine inflammatory cytokine response. RESULTS: A total of 33/56 (59%) of primary TKA synovial tissue samples were positive for PG by IHC, and PG staining colocalized with markers of synovial macrophages and fibroblasts by IFM. Synovial tissue inflammation and elevated IL-6 in synovial fluid positively correlated with PG positivity. Primary human fibroblasts stimulated with PG secreted high levels of IL-6, consistent with ex vivo findings. Interestingly, we observed a significant inverse correlation between PG and age at time of TKA, indicating younger age at time of TKA was associated with higher PG levels. CONCLUSION: Peptidoglycan is commonly found in synovial tissue from patients undergoing TKA. Our data indicate that PG may play an important role in inflammatory synovitis, particularly in patients who undergo TKA at a relatively younger age.