The Effect of BMI on 30 Day Outcomes Following Total Joint Arthroplasty

Patient-related risk factors for unplanned 30-day readmission following total knee arthroplasty: a protocol for a systematic review and meta-analysis

BACKGROUND

Osteoarthritis is a debilitating condition as well as a growing global health problem, and total knee arthroplasty is an effective treatment for advanced stages of disease. Unplanned 30-day hospital readmission is an indicator of complications, which is a significant financial burden on healthcare systems. The objective is to perform a systematic review of patient-related factors associated with unplanned 30-day readmission following total knee arthroplasty. This information will inform future strategies to improve health outcomes after knee arthroplasty surgery.

METHODS

MEDLINE and EMBASE will be systematically searched using a comprehensive search strategy. Studies of higher quality than case series will be included, in order to optimise the quality of the findings of this review. We will include studies reporting on patient-related risk factors for unplanned 30-day readmission following primary or revision total knee arthroplasty for any indication. Case series will be excluded, as will studies reporting exclusively on intraoperative, clinician, hospital, and health system risk factors. The reference lists of selected papers will then be screened for any additional literature. Two reviewers will independently apply stringent eligibility criteria to titles, abstracts, and full texts of studies identified in the literature search. They will then extract data from the final list of selected papers according to an agreed-upon taxonomy and vocabulary of the data to be extracted. Assessment of risk of bias and quality of evidence will then take place. Finally, the effect size of each identified risk factor will be determined; meta-analysis will be performed where adequate data is available.

DISCUSSION

The findings of this review and subsequent meta-analysis will aid clinicians as they seek to understand the risk factors for 30-day readmission following total knee arthroplasty. Clinicians and patients will be able to use this information to align expectations of the postoperative course, which will enhance the recovery process, and aid in the development of strategies to mitigate identified risks. Another purpose of this review is to assist policy-makers in developing quality indicators for care and provide insights into the drivers of health costs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019118154.

Higher BMI predicts additional surgery at the time of ACL reconstruction

PURPOSE

Despite public recognition, obesity is a growing epidemic affecting an estimated 34% of adults and 20% of children in the U.S.

POPULATION

As such, the number of ACL reconstructions performed in this population is likely to increase. The goal of this study is to evaluate the risk that increasing BMI poses for additional surgery at the time of ACL reconstruction.

METHODS

A retrospective analysis of the American College of Surgeons' National Surgical Quality Improvement Program's (ACS-NSQIP) database for the years 2005-2015 was conducted. Logistic regressions were used to assess the relationship between BMI and additional CPT codes for internal derangement at the time of ACL reconstruction. Internal derangement was defined as any CPT code for treatment of a meniscus tear, chondral lesion, or loose body removal. Surgeries for multi-ligamentous knee injuries were excluded.

RESULTS

A total of 11,403 patients undergoing ACL reconstruction were identified. 41.9% of patients had an associated CPT code for internal derangement. As BMI increased, there was a corresponding increase in the odds of additional surgery. Specifically, for every 1.0 increase in BMI, the risk of additional surgery increased by 1.6% (p < 0.001). Compared to patients with a BMI of 18.5-24.9, those with a BMI 25-29.9 had an odds ratio (OR) of 1.112, BMI 30-34.9 had an OR of 1.137, BMI 35-39.9 had an OR of 1.249, and those ≥ 40 had an OR of 1.442 for additional surgery (p < 0.001).

CONCLUSIONS

This nationally-representative, population-based study demonstrates that patients with elevated BMI are much more likely to require additional surgery in the setting of primary ACL reconstruction. This risk correlates with increasing BMI. Surgeons should keep these risks in mind when evaluating and counseling patients for surgery in the setting of ACL reconstruction.

LEVEL OF EVIDENCE

Case-control study, Level III.

Weight changes after total knee arthroplasty in Chinese patients: a matched cohort study regarding predictors and outcomes

BACKGROUND

The purpose of this study was to compare 2-year BMI changes between patients undergoing simultaneous bilateral total knee arthroplasty (TKA), staged bilateral TKA, and unilateral TKA. We also sought to determine the predictors of weight change and whether clinically meaningful weight changes affected outcomes.

PATIENTS AND METHODS

This retrospective, single-institution study included 202 Chinese patients who received simultaneously bilateral TKA, staged bilateral TKA, or unilateral TKA from 2008 to 2015. There were 49 simultaneous bilateral TKAs, 52 staged bilateral TKAs, and a matched 101 unilateral TKAs.

RESULTS

66.8% (135/202) of patients lost weight after TKA surgery. However, 20.7% (42/202) of patients experienced clinically meaningful weight loss (a BMI decrease of more than 5%). Paired t test showed that 2-year BMI was significantly lower than preoperative BMI (p < 0.001). Weight loss was significantly different between the surgical strategy (p < 0.001). Preoperative BMI and age were predictive of clinically significant weight loss or gain (p < 0.05). Multiple linear regression showed that post-operative weight loss was associated with better Western Ontario and McMaster Universities Osteoarthritis Index and SF-36 scores (p < 0.001).

CONCLUSION

Patients after TKA experience weight loss. Age and preoperative BMI predict clinically meaningful weight change. Simultaneous bilateral TKA is associated with higher likelihood of weight loss. Clinically meaningful weight loss experiences better patient-reported outcomes.

Preoperative Optimization Checklists Within the Comprehensive Care for Joint Replacement Bundle Have Not Decreased Hospital Returns for Total Knee Arthroplasty

BACKGROUND

The Comprehensive Care for Joint Replacement (CJR) model has resulted in the evolution of preoperative optimization programs to decrease costs and hospital returns. At the investigating institution, one center was not within the CJR bundle and has dedicated fewer resources to this effort. The remaining centers have adopted an 11 metric checklist designed to identify and mitigate modifiable preoperative risks. We hypothesized that this checklist would improve postoperative metrics that impact costs for total knee arthroplasty (TKA) patients eligible for participation in CJR.

METHODS

Patients undergoing TKA from 2014 to 2018 were retrospectively reviewed. Only patients with eligible participation in CJR were included. Outcome variables including length of stay, disposition, 90-day emergency department visits, and hospital readmissions were explored. Analysis was performed to determine differences in outcomes between CJR participating and non-CJR participating hospitals within the healthcare system.

RESULTS

In total, 2308 TKA patients including 1564 from a CJR participating center and 744 from a non-CJR center were analyzed. There was no significant difference in patient age or gender. Patients at the non-CJR hospital had significantly higher body mass index (P < .001) and American Society of Anesthesiologists scores (P < .001), while those in the CJR network had fewer skilled nursing facility discharges (P = .028) and shorter length of stay (P < .001). However, there was no reduction in 90-day emergency department visits or readmissions.

CONCLUSION

The resources utilized at CJR participating hospitals, including patient optimization checklists, did not effectively alter patient outcomes following discharge. Likely, a checklist alone is insufficient for risk mitigation and detailed optimization protocols for modifiable risk factors must be investigated.

The Effect of Body Mass Index on 30-day Complications After Revision Total Hip and Knee Arthroplasty

BACKGROUND

We aimed to explore the effect of body mass index (BMI) on 30-day complications after aseptic revision total knee arthroplasty (rTKA) and aseptic revision total hip arthroplasty (rTHA), considering BMI as both a categorical and continuous variable.

METHODS

A total of 18,866 patients (9093 rTHA and 9773 rTKA) patients were included for analysis using the American College of Surgeons National Surgical Quality Improvement Project database. Thirty-day rates of readmissions, reoperations, and major and minor complications were compared between different weight categories (overweight: BMI >25 and ≤30 kg/m²; obese: BMI >30 and ≤40 kg/m²; morbidly obese: BMI >40 kg/m²) and the normal weight category (BMI >18.5 and ≤25 kg/m²) using multivariate regression models. Spline regression models were created to study BMI as a continuous variable.

RESULTS

Both readmission rates and reoperation rates increased for rTKA as BMI increased (P < .005). There was a linear relationship between BMI and readmission rates for rTKA. Morbid obesity was associated with an increased reoperation rate for rTHA on univariate analysis (P = .022); however, multivariate analysis showed no statistically significant increase in readmission or reoperation rates as BMI increased for rTHA.

CONCLUSIONS

The relationship between BMI and complications after revision total joint arthroplasty is a J-shaped curve with the lowest rates of complications occurring around a BMI of 30 kg/m². The relationship between BMI and perioperative complications is stronger for revision TKA as opposed to revision THA.

Return to work after primary total hip arthroplasty: a nationwide cohort study

Background and purpose - While the number of working-age patients undergoing total hip arthroplasty (THA) is increasing, the effect of the surgery on patients' return to work (RTW) is not thoroughly studied. We aimed to identify risk factors of RTW after THA among factors related to demographic variables, general health, health risk behaviors, and socioeconomic status. Patients and methods - We studied 408 employees from the Finnish Public Sector (FPS) cohort (mean age 54 years, 73% women) who underwent THA. Information on demographic and socioeconomic variables, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of return to work was examined using Cox proportional hazard modeling. Results - 94% of the patients returned to work after THA on average after 3 months (10 days to 1 year) of sickness absence. The observed risk factors of successful return to work were: having < 30 sick leave days during the last year (HR 1.8; 95% CI 1.4-2.3); higher occupational position (HR 2.2; CI 1.6-2.9); and BMI < 30 (HR 1.4; CI 1.1-1.7). Age, sex, preceding health status, and health-risk behaviors were not correlated with RTW after the surgery. Interpretation - Most employees return to work after total hip arthroplasty. Obese manual workers with prolonged sick leave before the total hip replacement were at increased risk of not returning to work after the surgery.

Relationship between Body Mass Index and Complications during the First 45 Days after Primary Total Hip and Knee Replacement: A Single-Center Study from South America

Background

The goal of this study was to evaluate the relationship between body mass index (BMI) and early complications of total hip replacement (THR) and total knee replacement (TKR).

Methods

This is a retrospective study of patients who underwent primary THR and TKR between January 2011 and December 2015. We included patients between 18 and 90 years of age with BMI less than 40 kg/m² with a minimal postoperative follow-up time of 45 days. The primary outcomes were the presence of infection, mechanical complications (dislocation, fractures, arthrofibrosis, or neuropraxia), and thromboembolic events. Overweight and obesity were defined as a BMI of 25-29.9 kg/m² and ≥ 30 kg/m², respectively.

Results

In total 750 patients were included (THR, 268; TKR, 482) with a mean age of 65.0 ± 12.4 years. The percentage of patients with normal weight, overweight, and obesity was 24.9% (n = 187), 41.7% (n = 313), and 33.4% (n = 250), respectively. The early complication rate was 8.9% (95% confidence interval [CI], 7.1% to 11.2%). Infection and mechanical complications were most prevalent. There was no statistically significant relationship between the incidence of complications and BMI (obesity vs. normal weight: hazard ratio [HR], 1.49; 95% CI, 0.72 to 3.06; p = 0.282); however, there was a tendency toward a greater risk of infectious complications in the patients with obesity (HR, 6.08; 95% CI, 0.75 to 49.16; p = 0.090). Patients with diabetes mellitus (DM) had more risk of infectious complications than those without DM (HR, 2.60; 95% CI, 1.00 to 6.79).

Conclusions

There was no statistical relationship between BMI and early complications of THR and TKR. Nonetheless, there was a tendency toward a higher risk of infection in patients with some degree of obesity.

Four questions to identify patients with ASA III or higher

BACKGROUND

Increased age, obesity, and American Society of Anesthesiologists (ASA) Physical Status class III and IV have been reported as predictors for mortality and perioperative complications. High-volume institutions rely on central referral services as first contact point for patients. The current study reports on a simple four-step questionnaire to identify patients with ASA-physical status class III and IV to improve referral processes and optimize perioperative work ups.

MATERIALS AND METHODS

Seven hundred and seventy-five patients who called the physician referral service (PRS) at the author's institution and subsequently underwent surgery were enrolled in this study. The answers to the initial PRS questionnaire were analyzed. The study cohort consisted of 414 women (53.4%) and 361 men (46.6%) with an average age of 61.4 years (range 44-90 years) at the time of surgery.

RESULTS

Binary logistic regression revealed hypertension, diabetes mellitus (using medication), using blood thinner (other than Aspirin) and a number of 4-9 prescribed medication, respectively, as predictors for ASA III and IV. Receiver-operating characteristic (ROC) curve analysis identified a sensitivity of 82.4%, a specificity of 82.9%, and an accuracy of 82.8%, when two of these four questions are answered "yes". The area under the curve for this analysis was 0.876 [95% confidence interval (CI) 0.845-0.908]. Positive and negative likelihood ratios were 4.8 (95% CI 4.0-5.8) and 0.2 (95% CI 0.1-0.3), respectively.

CONCLUSIONS

This study revealed a simple four-step questionnaire to identify patients with ASA III or IV before a medical appointment. This helps to balance referrals between multiple providers in high-volume medical groups.

Use of Closed Incisional Negative Pressure Wound Therapy After Revision Total Hip and Knee Arthroplasty in Patients at High Risk for Infection: A Prospective, Randomized Clinical Trial

BACKGROUND

Continuous wound drainage after arthroplasty can lead to the development of a periprosthetic joint infection. Closed incisional negative pressure wound therapy (ciNPWT) has been reported to help alleviate drainage and other wound complications. The purpose of this prospective randomized controlled trial is to compare the use of ciNPWT with our standard of care dressing in revision arthroplasty patients who were at high risk to develop wound complications.

METHODS

A total of 160 patients undergoing elective revision arthroplasty were prospectively randomized to receive either ciNPWT or a silver-impregnated occlusive dressing after surgery in a single institution. Patients were included if they had at least 1 risk factor for developing wound complication(s): wound complication, readmission, and reoperation rates were collected at 2, 4, and 12 weeks postoperatively.

RESULTS

The postoperative wound complication rate was significantly higher in the control cohort compared to the ciNPWT cohort (19 [23.8%] vs 8 [10.1%], P = .022). There was no significant difference between the control and ciNPWT cohorts in terms of readmissions (19 [23.8%] vs 16 [20.3%], P = .595). Reoperation rate was higher in controls compared to ciNPWT patients (10 [12.5%] vs 2 [2.5%], P = .017). After adjusting for the history of a prior periprosthetic joint infection and inflammatory arthritis, the ciNPWT cohort had a significantly decreased wound complication rate (odds ratio 0.28, 95% confidence interval 0.11-0.68).

CONCLUSION

ciNPWT may decrease the rate of postoperative wound complications in patients who are at an increased risk of such wound issues after revision arthroplasty.

Risk stratification in primary total joint arthroplasty: the current state of knowledge

Background

As we transition to value-based care delivery models, risk stratification in total joint arthroplasty is more important than ever. The purpose of this study was to identify patients who would likely require higher level of care and may not be suitable for inclusion in bundled payment models.

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was queried for all patients who underwent primary total joint arthroplasty between 2011 and 2012. Five types of adverse events were assessed: medical complications, surgical complications, readmission, reoperation, and mortality. Univariate and multivariate logistic regression analyses were performed using a large number of demographic and morbidity variables.

Results

A total of 14,185 patients were identified. The 30-day medical complication, surgical complication, readmission, reoperation, and mortality rates were 2.0%, 3.2%, 4.0%, 1.5%, and 0.2%, respectively. Among the different variables assessed, only the American Society of Anesthesiologists (ASA) physical classification system was a significant risk factor for most outcomes assessed. Peripheral vascular disease was the most significant risk factor for medical complications and reoperation (odds ratio, 2.73 and 3.23, respectively). Bleeding disorders were the most significant risk factor for readmission and mortality (odds ratio, 2.03 and 5.86, respectively).

Conclusions

ASA score is a more reliable risk stratification tool than Charlson Comorbidity Index, but it is not sufficient by itself. Patients with higher ASA scores combined with peripheral vascular disease and/or bleeding disorders are at especially high risk of developing postsurgical adverse events and may not be suitable for inclusion in bundled payment models. These data can be used to develop better risk stratification models that are critically needed.

Control Strategies for Infection Prevention in Total Joint Arthroplasty

Despite the development of newer preventative measures, the rate of infection continues to be approximately 1% for patients undergoing total joint arthroplasty (TJA). The extent of the infection can range from a mild superficial infection to a more serious periprosthetic joint infection (PJI). PJIs not only play a significant role in the clinical well-being of the TJA patient population, but also have substantial economic implications on the health care system. Several approaches are currently being used to mitigate the risk of PJI after TJA. The variety of prophylactic measures to prevent infection after TJA must be thoroughly discussed and evaluated.

The Association of Body Mass Index with Risk of Long-Term Revision and 90-Day Mortality Following Primary Total Hip Replacement: Findings from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

BACKGROUND

The influence of obesity on outcomes following total hip replacement is unclear. Restriction of total hip replacement on the basis of body mass index (BMI) has been suggested. The purpose of this study was to assess the influence of BMI on the risk of revision and 90-day mortality.

METHODS

This was a population-based, longitudinal cohort study of the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man. Using data recorded from April 2003 to December 2015, linked to Office for National Statistics data, we ascertained revision and 90-day mortality rates following primary total hip replacement by BMI category. The probability of revision was estimated using Kaplan-Meier methods. Associations of BMI with revision and mortality were explored using adjusted Cox proportional hazards regression models.

RESULTS

We investigated revision and 90-day mortality among 415,598 and 413,741 primary total hip replacements, respectively. Each data set accounts for approximately 52% of the total number of recorded operations in the NJR. Thirty-eight percent of the patients were classified as obese. At 10 years, class-III obese patients had the highest cumulative probability of revision (6.7% [95% confidence interval (CI), 5.5% to 8.2%]), twice that of the underweight group (3.3% [95% CI, 2.2% to 4.9%]). When the analysis was adjusted for age, sex, American Society of Anesthesiologists [ASA] grade, year of operation, indication, and fixation type, compared with patients with normal BMI, significantly elevated hazard ratios (HRs) for revision were observed for patients in the BMI categories of class-I obese (≥30 to <35 kg/m) (HR, 1.14 [95% CI, 1.07 to 1.22]), class-II obese (≥35 to <40 kg/m) (HR, 1.30 [95% CI, 1.19 to 1.40]), and class-III obese (≥40 to ≤60 kg/m) (HR, 1.43 [95% CI, 1.27 to 1.61]) (p < 0.0005 for all). Underweight patients had a substantially higher cumulative probability of 90-day mortality (1.17%; 95% CI, 0.86% to 1.58%) compared with patients with normal BMI (0.43%; 95% CI, 0.39% to 0.48%). The risk of 90-day mortality was significantly higher for the underweight group (HR, 2.09 [95% CI, 1.51 to 2.89]; p < 0.0005) and significantly lower for patients who were categorized as overweight (HR, 0.70; 95% CI, 0.61 to 0.81; p < 0.0005), class-I obese (HR, 0.69 [95% CI, 0.59 to 0.81]; p < 0.0005), and class-II obese (HR, 0.79 [95% CI, 0.63 to 0.98]; p = 0.049) compared with patients with normal BMI.

CONCLUSIONS

Although long-term revision rates following total hip replacement were higher among obese patients, we believe that the rates remained acceptable by contemporary standards and were balanced by a lower risk of 90-day mortality.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Internal Validation of a Predictive Model for Complications After Total Hip Arthroplasty

BACKGROUND

Total hip arthroplasty (THA) is projected to increase in prevalence and associated complications will impose significant cost on the US healthcare system. The purpose of this study is to validate a predictive model for postoperative complications utilizing a novel 11-component hip-specific questionnaire encompassing preoperatively available clinical and radiographic data.

METHODS

Consecutive primary THA patients between January 2014 and January 2016 were included. Exclusion criteria included patients without questionnaire scoring variables and less than 1-year follow-up. Patients were stratified into 4 tiers based on their questionnaire score: low risk (>74), mild risk (57-73), moderate risk (41-56), and high risk (<40). A binary logistic regression was performed to determine if the questionnaire predicted complications. Receiver-operator curves were constructed to determine the threshold score below which there was a high likelihood of experiencing a complication.

RESULTS

Four hundred fifty patients were included in the final analysis with a mean (range) follow-up of 2.1 years (1.0-5.9), age of 63.1 years (25.7-9.17), and body mass index of 31.7 kg/m² (17.8-64.5). The complication rate was 13.6%. A hip questionnaire score of 73.8 conferred a 98.5% sensitivity and 98.5% negative predictive value for complications. The questionnaire score was the strongest predictor of a decreased complication likelihood (odds ratio 0.94, 95% confidence interval 0.90-0.97, P < .001). Risk tier was significantly associated with complications (low risk: 0; mild risk: 12; moderate risk: 25; and high risk: 24; P < .001).

CONCLUSION

This novel hip questionnaire demonstrated a high sensitivity and negative predictive value to identify patients at risk for postoperative complications. Future studies should attempt to prospectively validate the use of this questionnaire.

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.

Knee replacement

Knee replacement surgery is one of the most commonly done and cost-effective musculoskeletal surgical procedures. The numbers of cases done continue to grow worldwide, with substantial variation in utilisation rates across regions and countries. The main indication for surgery remains painful knee osteoarthritis with reduced function and quality of life. The threshold for intervention is not well defined, and is influenced by many factors including patient and surgeon preference. Most patients have a very good clinical outcome after knee replacement, but multiple studies have reported that 20% or more of patients do not. So despite excellent long-term survivorship, more work is required to enhance this procedure and development is rightly focused on increasing the proportion of patients who have successful pain relief after surgery. Changing implant design has historically been a target for improving outcome, but there is greater recognition that improvements can be achieved by better implantation methods, avoiding complications, and improving perioperative care for patients, such as enhanced recovery programmes. New technologies are likely to advance future knee replacement care further, but their introduction must be regulated and monitored with greater rigour to ensure patient safety.

Body mass index and in-hospital postoperative complications following primary total hip arthroplasty

BACKGROUND

The influence of obesity measured in terms of body mass index (BMI) on the complication rates following total hip arthroplasty (THA) is a matter of debate.

METHODS

This retrospective study conducted at a tertiary referral centre at Brisbane, Australia, examines the association between BMI and in-hospital postoperative complications, length of operating time and duration of hospital stay in 964 patients, who underwent THA from 2006 to 2010.

RESULTS

Amongst patients undergoing primary THA, when compared to the normal weight patients, those with BMI between 25 kg/m² and 29.9 kg/m² (overweight) and those with BMI between 35 kg/m² and 39.9 kg/m² (obese class II) had lower odds of perioperative complications (odds ratio [OR]: 0.62 (95% confidence intervals [CI], 0.43-0.92, p = 0.016) and OR: 0.60 (95% CI, 0.36- 0.99, p = 0.047 respectively). Patients with BMI less than or equal to 40 kg/m² were also associated with significantly lower odds of cardiac complications ( p = 0.02). With unadjusted regression analysis, it was noted that those with BMI ≥40 kg/m² had the highest odds of developing infectious complications (OR 2.68, 95% CI, 1.08-6.65, p < 0.05). As the BMI increased, there was a statistically significant increase in length of operating time ( p < 0.001).

CONCLUSION

There is a significant impact of BMI on the occurrence of perioperative complications following THA. Compared to normal weight category, the overweight and obese class II patients had a lower likelihood of developing overall, especially cardiac complications. Length of operating time increases along with an increase in BMI.

Does Surgeon Volume Affect Outcomes Following Primary Total Hip Arthroplasty? A Systematic Review

BACKGROUND

Surgeon volume has been identified as an important factor impacting postoperative outcome in patients undergoing orthopedic surgeries. With an absence of a detailed systematic review, we sought to collate evidence on the impact of surgeon volume on postoperative outcomes in patients undergoing primary total hip arthroplasty.

METHODS

PubMed (MEDLINE) and Google Scholar databases were queried for articles using the following search criteria: ("Surgeon Volume" OR "Provider Volume" OR "Volume Outcome") AND ("THA" OR "Total hip replacement" OR "THR" OR "Total hip arthroplasty"). Studies investigating total hip arthroplasty being performed for malignancy or hip fractures were excluded from the review. Twenty-eight studies were included in the final review. All studies underwent a quality appraisal using the GRADE tool. The systematic review was performed in accordance with the PRISMA guidelines.

RESULTS

Increasing surgeon volume was associated with a shorter length of stay, lower costs, and lower dislocation rates. Studies showed a significant association between an increasing surgeon volume and higher odds of early-term and midterm survivorship, but not long-term survivorships. Although complications were reported and recorded differently in studies, there was a general trend toward a lower postoperative morbidity with regard to complications following surgeries by a high-volume surgeon.

CONCLUSION

This systematic review shows evidence of a trend toward better postoperative outcomes with high-volume surgeons. Future prospective studies are needed to better determine long-term postoperative outcomes such as survivorship before healthcare policies such as regionalization and/or equal-access healthcare systems can be considered.

Are Medicare's "Comprehensive Care for Joint Replacement" Bundled Payments Stratifying Risk Adequately?

BACKGROUND

Bundled payments are meant to reduce costs and improve quality of care. Without adequate risk adjustment, bundling may be inequitable to providers and restrict access for certain patients. This study examines patient factors that could improve risk stratification for the Comprehensive Care for Joint Replacement (CJR) bundled-payment program.

METHODS

Ninety-five thousand twenty-four patients meeting the CJR criteria were retrospectively reviewed using administrative Medicare data. Multivariable regression was used to identify associations between patient factors and traditional (fee-for-service) Medicare reimbursement over the bundle period.

RESULTS

Average reimbursement was $18,786 ± $12,386. Older age, male gender, cases performed for hip fractures, and most comorbidities were associated with higher reimbursement (P < .05), except dementia (lower reimbursement; P < .01). Stratification incorporating these factors displayed greater accuracy than the current CJR risk adjustment methods (R² = 0.23 vs 0.17).

CONCLUSION

More robust risk stratification could provide more equitable reimbursement in the CJR program.

LEVEL OF EVIDENCE

Large database analysis; Level III.

Surgical Technical Evidence Review for Elective Total Joint Replacement Conducted for the AHRQ Safety Program for Improving Surgical Care and Recovery

Background:

Use of enhanced recovery pathways (ERPs) can improve patient outcomes, yet national implementation of these pathways remains low. The Agency for Healthcare Research and Quality (AHRQ; funder), the American College of Surgeons, and the Johns Hopkins Medicine Armstrong Institute for Patent Safety and Quality have developed the Safety Program for Improving Surgical Care and Recovery—a national effort to catalyze implementation of practices to improve perioperative care and enhance recovery of surgical patients. This review synthesizes evidence that can be used to develop a protocol for elective total knee arthroplasty (TKA) and total hip arthroplasty (THA).

Study Design:

This review focuses on potential components of the protocol relevant to surgeons; anesthesia components are reported separately. Components were identified through review of existing pathways and from consultation with technical experts. For each, a structured review of MEDLINE identified systematic reviews, randomized trials, and observational studies that reported on these components in patients undergoing elective TKA/THA. This primary evidence review was combined with existing clinical guidelines in a narrative format.

Results:

Sixteen components were reviewed. Of the 10 preoperative components, most were focused on risk factor assessment including anemia, diabetes mellitus, tobacco use, obesity, nutrition, immune-modulating therapy, and opiates. Preoperative education, venous thromboembolism (VTE) prophylaxis, and bathing/Staphylococcus aureus decolonization were also included. The routine use of drains was the only intraoperative component evaluated. The 5 postoperative components included early mobilization, continuous passive motion, extended duration VTE prophylaxis, early oral alimentation, and discharge planning.

Conclusion:

This review synthesizes the evidence supporting potential surgical components of an ERP for elective TKA/THA. The AHRQ Safety Program for Improving Surgical Care and Recovery aims to guide hospitals and surgeons in identifying the best practices to implement in the surgical care of TKA and THA patients.

Identifiable risk factors for thirty-day complications following arthroscopic rotator cuff repair

OBJECTIVES

Shoulder arthroscopy has increased in frequency over the past decade, with rotator cuff repair comprising the majority of cases performed. Prior studies have detailed risk factors for 30-day complications and readmission rates after arthroscopic shoulder surgery using the National Surgical Quality Improvement Program (NSQIP) database, but no study has specifically looked at arthroscopic rotator cuff repair. The purpose of the study is to evaluate the risk factors for 30-day complications following arthroscopic rotator cuff repair using the NSQIP database.

METHODS

The NSQIP database was queried for all patients undergoing arthroscopic rotator cuff repair from 2006-2015. Demographics and thirty-day outcomes for these patients were analyzed using univariate analyses and multivariate regression analysis to determine the risk factors for complications.

RESULTS

21,143 patients underwent arthroscopic rotator cuff repair, with 147 patients (0.70%) having a complication within 30-days. Univariate analysis found age >65 (p = 0.0028), male gender (p = 0.0053), elevated BMI (p = 0.0054), ASA class >2 (p < 0.0001), history of chronic obstructive pulmonary disease (p < 0.0001), hypertension (p < 0.0002), dyspnea (p < 0.0001), steroid use (p = 0.0350), and operative time >90 min (p = 0.0316) to be associated with increased risk of complications. Multivariate analysis found female sex to be protective or complication (OR 0.56, p = 0.0017), while American Society of Anesthesiology (ASA) class >2 (OR 1.51, p = 0.0335) and history of COPD (OR 2.41, p = 0.0030) and dyspnea (OR 1.89, p = 0.0359) to be risk factors for complication. The most common complication is venothromboembolic events, accounting for 36.7% of all complications.

CONCLUSION

Male sex, ASA class > 2, and history of COPD and dyspnea were independent risk factors for thirty-day complications following arthroscopic rotator cuff repair.

LEVEL OF EVIDENCE

IV.

Total Joint Arthroplasty in Ambulatory Surgery Centers: Analysis of Disqualifying Conditions and the Frequency at Which They Occur

BACKGROUND

The frequency of total joint arthroplasties (TJAs) performed in ambulatory surgery centers (ASCs) is increasing. However, not all TJA patients are healthy enough to safely undergo these procedures in an ambulatory setting. We examined the percentage of arthroplasty patients who would be eligible to have the procedure performed in a free-standing ASC and the distribution of comorbidities making patients ASC-ineligible.

METHODS

We reviewed the charts of 3444 patients undergoing TJA and assigned ASC eligibility based on American Society of Anesthesiologists (ASA) status, a set of exclusion criteria, and any existing comorbidities.

RESULTS

Overall, 70.03% of all patients undergoing TJA were eligible for ASC. Of the ASA class 3 patients who did not meet any exclusion criteria but had systemic disease (51.11% of all ASA class 3 patients), 53.69% were deemed ASC-eligible because of sufficiently low severity of comorbidities. The most frequent reasons for ineligibility were body mass index >40 kg/m² (32.66% of ineligible patients), severity of comorbidities (28.00%), and untreated obstructive sleep apnea (25.19%).

CONCLUSION

A large proportion of TJA patients were found to be eligible for surgery in an ASC, including over one-third of ASA class 3 patients. ASC performed TJA provides an opportunity for increased patient satisfaction and decreased costs, selecting the right candidates for the ambulatory setting is critical to maintain patient safety and avoid postoperative complications.

Effect of Obesity on Pain and Functional Recovery Following Total Knee Arthroplasty

BACKGROUND

While obesity may be a risk factor for complications following total knee arthroplasty, data remain sparse on the impact of the degree of obesity on patient-reported outcomes following this procedure. Our objective was to determine the extent to which obesity level affects the trajectory of recovery as well as patient-reported pain, function, and satisfaction with surgery following total knee arthroplasty.

METHODS

We followed a cohort of patients who underwent total knee arthroplasty at 1 of 4 medical centers. Patients were ≥40 years of age with a primary diagnosis of osteoarthritis. We stratified patients into 5 groups according to the World Health Organization classification of body mass index (BMI). We assessed the association between BMI group and pain and function over the time intervals of 0 to 3, 3 to 6, and 6 to 24 months using a piecewise linear model. We also assessed the association between BMI group and patient-reported outcomes at 24 months. Multivariable models adjusted for age, sex, race, diabetes, musculoskeletal functional limitations index, pain medication use, and study site.

RESULTS

Of the 633 participants included in our analysis, 19% were normal weight (BMI of <25 kg/m), 32% were overweight (BMI of 25 to 29.9 kg/m), 27% were class-I obese (BMI of 30 to 34.9 kg/m), 12% were class-II obese (BMI of 35 to 39.9 kg/m), and 9% were class-III obese (BMI of ≥40 kg/m). Study participants with a higher BMI had worse preoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores and had greater improvement from baseline to 3 months. The mean change in pain and function from 3 to 6 and from 6 to 24 months was similar across all BMI groups. At 24 months, participants in all BMI groups had similar levels of pain, function, and satisfaction.

CONCLUSIONS

Because of the differential trajectory of recovery in the first 3 months following total knee arthroplasty, the participants in the higher BMI groups were able to attain absolute pain and function scores similar to those in the nonobese and class-I obese groups. These data can help surgeons discuss expectations of pain relief and functional improvement with total knee arthroplasty candidates with higher BMI.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Current Risk Adjustment and Comorbidity Index Underperformance in Predicting Post-Acute Utilization and Hospital Readmissions After Joint Replacements: Implications for Comprehensive Care for Joint Replacement Model

OBJECTIVE

To compare the performances of 3 comorbidity indices, the Charlson Comorbidity Index, the Elixhauser Comorbidity Index, and the Centers for Medicare & Medicaid Services (CMS) risk adjustment model, Hierarchical Condition Category (HCC), in predicting post-acute discharge settings and hospital readmission for patients after joint replacement.

METHODS

A retrospective study of Medicare beneficiaries with total knee replacement (TKR) or total hip replacement (THR) discharged from hospitals in 2009-2011 (n = 607,349) was performed. Study outcomes were post-acute discharge setting and unplanned 30-, 60-, and 90-day hospital readmissions. Logistic regression models were built to compare the performance of the 3 comorbidity indices using C statistics. The base model included patient demographics and hospital use. Subsequent models included 1 of the 3 comorbidity indices. Additional multivariable logistic regression models were built to identify individual comorbid conditions associated with high risk of hospital readmissions.

RESULTS

The 30-, 60-, and 90-day unplanned hospital readmission rates were 5.3%, 7.2%, and 8.5%, respectively. Patients were most frequently discharged to home health (46.3%), followed by skilled nursing facility (40.9%) and inpatient rehabilitation facility (12.7%). The C statistics for the base model in predicting post-acute discharge setting and 30-, 60-, and 90-day readmission in TKR and THR were between 0.63 and 0.67. Adding the Charlson Comorbidity Index, the Elixhauser Comorbidity Index, or HCC increased the C statistic minimally from the base model for predicting both discharge settings and hospital readmission. The health conditions most frequently associated with hospital readmission were diabetes mellitus, pulmonary disease, arrhythmias, and heart disease.

CONCLUSION

The comorbidity indices and CMS-HCC demonstrated weak discriminatory ability to predict post-acute discharge settings and hospital readmission following joint replacement.

Improving Quality and Decreasing Cost by Reducing Re-admissions in Patients Undergoing Total Joint Arthroplasty

PURPOSE OF REVIEW

Total joint arthroplasty (TJA) has had an increased demand over the recent years. It is a successful procedure, and there are relatively few complications, but there is a high overall cost. There is a push to increase the quality of care, lessen complications, and decrease cost by reducing readmissions. This article will discuss the risk factors that can contribute to the complication and readmission rates following TJA.

RECENT FINDINGS

Several risk factors have been found to contribute to the complication and readmission rates following a TJA. It is important to understand these risk factors and mitigate them as much as possible in order to optimize the patient experience. There are risk factors that cannot be modified, and the treatment team as well as the patient should be made aware of these and account for them when making the decision whether to undergo elective primary TJA or not. In general, an increased number of risk factors is associated with increased complications and increased readmission rates. At our institution, we have used this knowledge to improve our outcomes and decrease costs. It is important to be mindful of risk factors for poor outcomes prior to performing TJA. This allows for the optimization of patients prior to undergoing surgery. This can lead to improved outcomes at a lower cost.

Is decreasing mortality in total hip and knee arthroplasty patients dependent on patients' comorbidity?

Background and purpose - Mortality after primary total hip and knee arthroplasty (THA and TKA) has declined, and the proportion of THA and TKA patients with comorbid conditions has increased. We therefore wanted to examine changes in comorbidity burden over time and the impact of comorbid on mortality following primary total hip and knee arthroplasty in patients with osteoarthritis. Patients and methods - We used the Danish arthroplasty registers to identify THA and TKA patients from 1996 through 2013. From administrative databases, we collected data on pre-surgery hospital history for all patients, which were used to calculate the Charlson comorbidity index (CCI). Patients were divided into 4 groups: CCI-none, CCI-low, CCI-moderate, and CCI-high. We calculated the relative risk (RR) of mortality within 90 days after surgery with a 95% confidence interval (CI), with stratification according to CCI group and year of surgery. Results - 99,962 THAs and 63,718 TKAs were included. The proportion of THAs with comorbidity increased by 3-4% in CCI-low, CCI-moderate, and CCI-high patients, from 1996-1999 to 2010-2013. The overall 90-day mortality risk declined for both procedures. Compared to CCI-none, THA patients with low, moderate, and high comorbidity burdens had an RR of 90-day mortality of 1.9 (95% CI: 1.6-2.4), 1.9 (CI: 1.5-2.5), and 3.3 (CI: 2.6-4.2), respectively. Similar increases in proportions and RRs were observed in TKAs. Interpretation - Despite the fact that the proportion of THA and TKA patients with comorbidities has increased over the past 18 years, the overall mortality has declined. The mortality risk depended on the comorbidity burden and did not decline during the study period for THA and TKA patients with a moderate or high comorbidity burden at the time of surgery.

Morbid Obesity and Total Knee Arthroplasty: A Growing Problem

Obesity is an epidemic, with approximately 35% of the US population affected. This rate is unlikely to decline and may increase the demand for total knee arthroplasty (TKA). Data regarding the risks, benefits, and potential complications of TKA in this patient population are conflicting. Preoperative considerations are optimization of nutritional status, safe weight loss strategies, and bariatric surgery. Intraoperative concerns unique to this population include inadequate exposure, implant alignment, and durable implant fixation; postoperative issues include tibial loosening, wound complications, cardiovascular events, and respiratory complications. A thorough understanding of the medical and surgical complications associated with TKA in the obese patient will facilitate research efforts and improve outcomes.

Frailty Index as a Predictor of Adverse Postoperative Outcomes in Patients Undergoing Cervical Spinal Fusion

STUDY DESIGN

Retrospective study of prospectively collected data.

OBJECTIVE

To investigate the applicability of the modified frailty index (mFI) as a predictor of adverse postoperative events in patients undergoing anterior cervical discectomy and fusion (ACDF) or posterior cervical fusion (PCF).

SUMMARY OF BACKGROUND DATA

Prior studies have investigated the mFI and shown it as an independent predictor of adverse postoperative outcomes across multiple surgical specialties. However, this topic has not still been studied in patients undergoing cervical fusion or in spinal surgery.

METHODS

The National Surgical Quality Improvement Program is a multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from about 400 hospitals nationwide. Current Procedural Terminology codes were used to query the database for adults who underwent elective ACDF and PCF between 2005 and 2012. The mFI was calculated for each patient. Univariate analysis and multivariate logistic regression were used to analyze the mFI as a predictor for postoperative complications.

RESULTS

For ACDF group, Clavien-Dindo grade IV complications rate increased from 0.8% to 9.0% as mFI increased from 0 to ≥0.27, and mFI = 0.27 was found to be an independent predictor of Clavien-Dindo grade IV complications (odds ratio, OR, = 4.67, 95% confidence interval, CI, = 2.27-9.62, P < 0.001). For PCF groups, Clavien-Dindo grade IV complications rate increased from 0.7% to 20.0% as mFI increased from 0 to ≥0.36, and mFI ≥ 0.36 was identified as an independent predictor of Clavien-Dindo grade IV complications (OR = 41.26, 95% CI = 6.62-257.15, P < 0.001).

CONCLUSION

The mFI was shown to be an independent predictor of Clavien-Dindo grade IV complications in patients undergoing ACDF or PCF. The mFI itself may be used to stratify risks in patients undergoing cervical fusion, or, the mFI scheme could be used as a platform upon which more efficient risk stratification could be done with addition of other variables.

LEVEL OF EVIDENCE

4.

Strategies to Prevent Periprosthetic Joint Infection After Total Knee Arthroplasty and Lessen the Risk of Readmission for the Patient

There is yet to be a standardized total knee arthroplasty (TKA) surgical protocol that has been studied to a sufficient degree to offer evidence-based practices regarding infection and readmission prevention. Although high-level evidence is often sought to provide guidance concerning protocol- and process-level decisions, the literature is often confusing and nondefinitive in its conclusions and recommendations regarding periprosthetic joint infection and readmission prevention. Areas of study that require further investigation include the following: the role of patient optimization and preoperative mitigation of risk; perioperative antibiotics; operating room environment; blood management; operative techniques, implants, and infection prevention measures; wound care management; and post acute care. Patient-associated modifiable risk must be optimized to decrease poly joint infection rates after TKA. Protocol measures for TKA need to be standardized, and evidence-based practice measures need to be validated.

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.

Elevated Body Mass Index Is Associated With Early Total Knee Revision for Infection

BACKGROUND

Obesity affects over half a billion people worldwide, including one-third of men and women in the United States. Obesity is associated with higher postoperative complication rates after total knee arthroplasty (TKA). It remains unknown whether obese patients progress to revision TKA faster than nonobese patients.

METHODS

A total of 666 consecutive primary TKAs referred to an academic tertiary care center for revision TKA were retrospectively stratified according to body mass index (BMI), reason for revision TKA, and time from primary to revision TKA.

RESULTS

When examining primary TKAs referred for revision TKA, increasing BMI adversely affected the mean time to revision TKA. The percent of referred TKAs revised by 5 years was 54% for a normal BMI, 64% for an overweight patient, 71% for an obese class I patient, 68% for an obese class II patient, and 73% for a morbidly obese patient. There was a significant difference in time to revision TKA between patients with normal BMI and elevated BMI (P = .005). There was a significant increase in early revision TKA for infection in patients with an elevated BMI (54%, 74/138) when compared with the normal BMI patients (24%, 8/33, P < .003, relative risk ratio = 2.3, absolute risk = 30%, number needed to treat = 3.3). There was no significant increase in acute, early, midterm, or late revision TKA for aseptic loosening and/or osteolysis, instability, stiffness, or other causes between patients with normal BMI and elevated BMI.

CONCLUSION

An elevated BMI is a risk factor for early referral to a tertiary care center for revision TKA. Specifically, orthopedic surgeons should convey to overweight and obese patients that they have at least a 130% increased relative risk and a 30% absolute risk of revision TKA for an early infection if referred for revision TKA. Patient expectations and counseling as well as reimbursement should account for the greater risks when performing a TKA on patients with an elevated BMI.

Shoulder Arthroplasty Outcomes in Patients With Multiple Reported Drug Allergies: Does Number of Drug Allergies Have an Effect on Outcome?

Background:

The presence of multiple allergies has been correlated with worse outcomes for patients undergoing hip and knee arthroplasty, but the effect of allergies has not yet been elucidated with respect to shoulder arthroplasty.

Purpose/Hypothesis:

The purpose of this study is to identify any discrepancies in shoulder arthroplasty outcomes with respect to reported drug allergies. We hypothesized that patients with multiple drug allergies would have inferior outcomes.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included in the analysis were a single surgeon’s cases between 2009 and 2014 of primary total shoulder arthroplasty with a minimum of 180 days of follow-up. Cases with fracture as the indication were excluded. Preoperative and postoperative metrics included visual analog scale (VAS) for pain, forward flexion range of motion, and Simple Shoulder Test (SST) results, and postoperative patient satisfaction scores were also collected. Chi-square and 1-way analysis of variance with Tukey post hoc analyses were performed when appropriate.

Results:

A total of 98 patients were included (no allergies, n = 51; single allergy, n = 21; multiple allergies, n = 26). The proportion of females was greater with increasing number of allergies (no allergies, 31%; single allergies, 47%; multiple allergies, 88%; Pearson χ² = 22.5; P < .0001). Both preoperatively and postoperatively, no difference was found between cohorts with respect to SST score, VAS score, or forward flexion. There was also no difference in postoperative satisfaction between cohorts. No difference between cohorts was identified when comparing the pre- to postoperative change in SST scores, VAS scores, or forward flexion.

Conclusion:

The presence of single or multiple allergies is not correlated with worse outcomes after primary anatomic total shoulder arthroplasty.

Risk Factors for Wound Complications After Direct Anterior Approach Hip Arthroplasty

BACKGROUND

Previous studies have suggested that wound complications may be higher after direct anterior approach (DAA) hip arthroplasty, but, specific risk factors have not been closely examined.

METHODS

We conducted a retrospective case-control study of 651 consecutive DAA hip arthroplasty surgeries performed by 2 surgeons over a 3-year period. Outcome measures included any postoperative wound problem (including prolonged drainage, wound dehiscence, wound necrosis, suture granuloma, and superficial infection) requiring additional intervention or reoperation. Univariate odds ratios (ORs) were calculated, and multivariate logistic regression analysis was performed to determine risk correlation. Receiver operator characteristic (ROC) curves were created to determine disease predictability.

RESULTS

A total of 75 patients (11.5%) experienced wound complications requiring additional intervention, of which, 13 (1.9%) required reoperation. Multivariate regression analysis found that development of wound complications was significantly and independently associated with body mass index (BMI) 30-35 kg/m² (OR 2.05; 95% confidence interval [CI] 1.08-3.88), BMI 35-40 kg/m² (OR 3.40; 95% CI 1.42-8.26), BMI > 40 kg/m² (OR 7.28; 95% CI 2.55-20.78), and diabetes mellitus (OR 2.97; 95% CI 1.46-6.07). Reoperation for wound complication was significantly associated with BMI > 40 kg/m² (OR 5.68; 95% CI 1.17-27.48) and diabetes mellitus (OR 13.08; 95% CI 3.97-43.11). Optimal cutoff values for BMI were found through receiver operator characteristic curve analysis to be 28.0 kg/m² for development of wound complications and 28.2 kg/m² for reoperation for wound complications.

CONCLUSION

Obesity and diabetes mellitus are significantly associated with postoperative wound-healing complications and the need for reoperation for these wound complications after DAA hip arthroplasty.

Does Marital Status Impact Outcomes After Total Knee Arthroplasty?

BACKGROUND

There is a paucity of research on the relationship between marital status and patient outcomes following total knee arthroplasty (TKA).

METHODS

This was a retrospective chart review of patients who underwent TKA by a single surgeon at a university-based orthopedic practice. Data abstracted included age, gender, marital status, body mass index, length of hospital stay, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Oxford Knee Score (OKS). The WOMAC and OKS were administered at the preoperative visit and at approximately 10, 30, 90, and 180 days after TKA. Multivariate analyses with patient-reported outcomes as repeated measures, marital status, day of assessment; and the interaction of marital status and day of assessment as fixed effects; and age, gender, body mass index, and length of hospital stay as covariates were conducted as well as analyses in which preoperative patient-reported outcomes were treated as fixed effects.

RESULTS

Of 422 patients who underwent TKA during the study period, complete data were available for 249, of whom 124 were married and 125 unmarried. Married patients had significantly higher WOMAC scores than unmarried patients at all postoperative assessments, even after controlling for preoperative scores. Although married patients also had significantly higher postoperative OKS scores than their unmarried peers, differences between groups were attenuated after adjusting for preoperative OKS scores.

CONCLUSION

This study found that married patients have better overall outcomes after TKA but yielded conflicting results as to whether the positive effects of marriage are specific to the postoperative period.

Simplified Frailty Index as a Predictor of Adverse Outcomes in Total Hip and Knee Arthroplasty

BACKGROUND

The modified frailty index (mFI) has been shown to predict adverse outcomes in multiple nonorthopedic surgical specialties. This study aimed to assess whether mFI is a predictor of adverse events in patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

Patients who underwent THA and TKA from 2005-2012 were identified in the National Surgical Quality Improvement Program database. mFI was calculated for each patient using 15 variables found in National Surgical Quality Improvement Program. Bivariate and multivariate analyses of postoperative adverse events, including Clavien-Dindo grade IV complications, were performed.

RESULTS

A total of 14,583 THA and 25,223 TKA patients were included for analysis. The mean (standard deviation, range) mFIs were 0.083 (0.080, 0-0.55) for THA and 0.097 (0.080, 0-0.64) for TKA cohorts. On bivariate analyses, incidence of Clavien-Dindo grade IV complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), hospital-acquired conditions (surgical site infection, venous thromboembolism, and urinary tract infection), any complications, and mortality increased significantly with increase in mFI (P < .0001 for all). Adjusting for demographics, age ≥ 75, body mass index ≥40, American Society of Anesthesiologists class ≥4, and nonclean wound status, mFI ≥0.45 was shown to be the strongest independent predictor of Clavien-Dindo grade IV complications for both THA and TKA cohorts with odds ratios of 5.140 and 4.183, respectively.

CONCLUSION

mFI ≥0.45 is an independent predictor of Clavien-Dindo grade IV complications in TKA/THA patients with greater odds ratios than age >75, body mass index ≥40, American Society of Anesthesiologists class ≥4. mFI should be considered for risk stratifying joint arthroplasty patients preoperatively and perhaps determining immediate postoperative destination.

Superficial wound infection does not cause inferior clinical outcome after TKA

PURPOSE

Superficial wound infections do not lead to chronic prosthetic joint infection. Therefore, it has been hypothesized that a superficial infection of a surgical wound following a successfully treated TKA does not lead to a lower functional outcome at long-term follow-up. This may be due to early diagnosis and proper treatment without interrupting the rehabilitation programme. The purpose of this study was to support the hypothesis by comparing the functional outcome and health-related quality of life (HRQoL) of superficial infections treated successfully after primary total knee arthroplasty (TKA).

METHODS

In a 3000 prospective TKA cohort, 45 superficial infections were compared to a control group of 629 TKA without complications. The functional outcome, health quality, expectations and revision rate were compared between the study and control groups.

RESULTS

The groups were comparable in terms of demographic values and preoperative scores. The mean follow-up was 74.57 months (SD ± 7.1). No statistical differences were observed relative to functional outcomes at the final follow-up as measured with the Knee Society Score (156.9 vs 168.4; n.s) and range of motion (0.2-114.4 vs 0.7-112.3; n.s). For the HRQoL, no differences in the physical (40.0 vs 40.6; n.s) and mental (43.2 vs 45.8; n.s) SF-36 scores were found. Neither were there differences in post-operative expectations and the revision rate.

CONCLUSIONS

In a long-term follow-up, a different clinical outcome and HRQoL were not obtained after a successfully treated superficial infection following a TKA when compared to a TKA without complications. Based on the findings of the study, additional complications are not anticipated after a successfully treated superficial wound infection in TKA. Therefore, a different follow-up to that of a non-complicated TKA is not recommended when the early post-operative superficial wound infection has been appropriately treated. A superficial infection successfully treated in the acute post-operative period should be considered solved at long-term follow-up.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

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.

Factors influencing length of hospital stay after primary total knee arthroplasty in a fast-track setting

PURPOSE

The goal of this study was to identify factors prior to surgery that are associated with an increased length of hospital stay after TKA using a fast-track protocol.

MATERIALS AND METHODS

In total, 879 consecutive patients who underwent primary TKA were included in this retrospective cohort study. A length of stay greater than or equal to three nights was considered an increased length of hospital stay. Univariable and multivariable generalized linear mixed models were used to identify potential factors associated with increased length of hospital stay.

RESULTS

Length of hospital stay was significantly associated with age [OR 1.01 (95 % CI 1.01-1.02); p < 0.001], gender [female vs. male, OR 1.07 (95 % CI 1.00-1.15); p = 0.04], ASA [ASA III/IV vs. ASA I, OR 1.22 (95 % CI 1.06-1.39); p = 0.005], living situation (alone vs. together, OR 1.08 (95 % CI 1.00-1.16); p = 0.04], neurological comorbidities [OR 1.14 (95 % CI 1.06-1.23); p < 0.001], musculoskeletal comorbidities [OR 0.91 (95 % CI 0.85-0.97); p = 0.005], anaesthesia [spinal vs. general, OR 0.86 (95 % CI 0.76-0.97); p = 0.02], and weekday of surgery [Thursday vs. Monday, OR 1.12 (95 % CI 1.02-1.23); p = 0.02].

CONCLUSIONS

Older age, female gender, ASA III/IV, people living alone, the presence of neurological comorbidities, general anaesthesia and surgery on Thursday were associated with an increased length of hospital stay. In clinical practice, the knowledge of factors associated with an increased length of hospital stay can be used to further optimize peri-operative protocols for patients at risk for an increased length of hospital stay after TKA.

LEVEL OF EVIDENCE

II.

Joint arthroplasty Perioperative Surgical Home: Impact of patient characteristics on postoperative outcomes

AIM: To determine the impact of different characteristics on postoperative outcomes for patients in a joint arthroplasty Perioperative Surgical Home (PSH) program.

METHODS: A retrospective review was performed for patients enrolled in a joint arthroplasty PSH program who had undergone primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). Patients were preoperatively stratified based on specific procedure performed, age, gender, body mass index (BMI), American Society of Anesthesiologists Physical Classification System (ASA) score, and Charleston Comorbidity Index (CCI) score. The primary outcome criterion was hospital length of stay (LOS). Secondary criteria including operative room (OR) duration, transfusion rate, Post-Anesthesia Care Unit (PACU) stay, readmission rate, post-operative complications, and discharge disposition. For each outcome, the predictor variables were entered into a generalized linear model with appropriate response and assessed for predictive relationship to the dependent variable. Significance level was set to 0.05.

RESULTS: A total of 337 patients, 200 in the TKA cohort and 137 in the THA cohort, were eligible for the study. Nearly two-third of patients were female. Patient age averaged 64 years and preoperative BMI averaged 29 kg/m². The majority of patients were ASA score III and CCI score 0. After analysis, ASA score was the only variable predictive for LOS (P = 0.0011) and each increase in ASA score above 2 increased LOS by approximately 0.5 d. ASA score was also the only variable predictive for readmission rate (P = 0.0332). BMI was the only variable predictive for PACU duration (P = 0.0136). Specific procedure performed, age, gender, and CCI score were not predictive for any of the outcome criteria. OR duration, transfusion rate, post-operative complications or discharge disposition were not significantly associated with any of the predictor variables.

CONCLUSION: The joint arthroplasty PSH model reduces postoperative outcome variability for patients with different preoperative characteristics and medical comorbidities.

Morbidity and mortality after bilateral simultaneous total knee arthroplasty in a fast-track setting

Background and purpose - The safety aspects of bilateral simultaneous total knee arthroplasty (BSTKA) are still debated. In this retrospective single-center study, we investigated early morbidity and mortality following BSTKA in a modern fast-track setting. We also identified risk factors for re-admission within 90 days and for a length of stay (LOS) of more than 5 days. Patients and methods - 284 patients were selected to receive BSTKA at our institution from 2008 through 2014 in a well-described, standardized fast-track setup (Husted 2012a, b). All re-admissions within 90 days were identified and mortality rates and time until death were recorded. Transfusion rates and numbers of transfusions were also recorded. Logistic regression analysis was used to identify risk factors for re-admission within 90 days, and also for a LOS of more than 5 days. Results - 90-day mortality was 0%. 10% of the patients were re-admitted within 90 days. Median time to re-admission was 18 (3-75) days. 153 patients (54%) received postoperative blood transfusions. An ASA score of 3 was identified as an independent risk factor for re-admission within 90 days (OR = 5, 95% CI: 1.3-19) and for LOS of > 5 days (OR = 6, 95% CI: 1.6-21). Higher BMI was a weak risk factor for re-admission within 90 days. Interpretation - BSTKA in selected patients without cardiopulmonary disease in a fast-track setting appears to be safe with respect to early postoperative morbidity and mortality. Surgeons should be aware that patients with an ASA score of 3 have an increased risk of re-admission and a prolonged length of stay, while patients with higher BMI have an increased risk of re-admission following BSTKA.

Does Body Mass Index Decrease Over Time Among Patients Who Undergo Total Knee Arthroplasty Compared to Patients With Osteoarthritis? Data From the Osteoarthritis Initiative

BACKGROUND

Although total knee arthroplasty (TKA) is associated with improved patient-reported function, pain, and quality of life, the effects on weight loss are less certain. In this study, we use data from a large, prospective cohort study of osteoarthritis (OA) patients to compare the changes in body mass index (BMI) across 6 years in OA patients who received TKA compared with OA patients who did not receive TKA.

METHODS

Using data from the Osteoarthritis Initiative, a prospective cohort study of patients with OA, our study divided patients into two groups: patients who received a TKA during the Osteoarthritis Initiative study (N = 140) and those who did not (N = 697). The initial BMI, final BMI, and change in weight over 72 months were compared between groups. Subgroup analysis was performed by dividing patients by their initial BMI, gender, and age.

RESULTS

The TKA group's change in weight, initial BMI, and final BMI were not significantly different from the non-TKA group over 72 months (weight change: -0.763 kg vs +0.191 kg; P = .597). Subgroups of women and patients aged 51-60 years with TKA gained more weight than respective non-TKA OA patients.

CONCLUSIONS

Overall, patients who received TKA did not lose or gain more weight than OA patients who did not receive TKA. Patients with longer follow-up after TKA (>2 years) still gained weight on average. Despite the improved patient-reported pain levels, function, and quality of life after TKA, it appears that TKA alone is not a sufficient intervention for obesity.

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.