Morbid Obesity and Total Knee Arthroplasty: A Growing Problem

The Removal of Total Knee Arthroplasty From the Inpatient-Only List has Improved Patient Optimization

INTRODUCTION

On January 1, 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only (IPO) list, expanding outpatient TKA (oTKA) to include patients with insurance coverage through their programs. These regulatory changes reinforced the need for preoperative optimization to ensure a safe and timely discharge after surgery. This study compared modifiable preoperative optimization metrics in patients who underwent oTKA pre-IPO and post-IPO removal. The authors hypothesized that patients post-IPO removal would demonstrate improvement in the selected categories.

METHODS

Outpatient TKA in a national database was identified and stratified by surgical year (2015 to 2017 versus 2018 to 2020). Preoperative optimization thresholds were established for the following modifiable risk factors: albumin, hematocrit, sodium, smoking, and body mass index. The percentage of patients who did not meet thresholds pre-IPO and post-IPO removal were compared.

RESULTS

In total, 2,074 patients underwent oTKA from 2015 to 2017 compared with 46,480 from 2018 to 2020. Patients undergoing oTKA after IPO removal were significantly older (67.0 versus 64.4 years; P < 0.01). A lower percentage of patients in the post-IPO cohort fell outside the threshold for all modifiable risk factors. Results were significant for preoperative sodium (10.7% versus 8.8%; P < 0.01), body mass index (12.4% versus 11.0% P = 0.05), and smoking history (9.9% versus 6.6%; P < 0.01).

CONCLUSION

Outpatient TKA has increased considerably post-IPO removal. As this regulatory change has allowed older patients with increased comorbidities to undergo oTKA, the need for appropriate preoperative optimization has increased. The current data set demonstrates that surgeons have improved preoperative optimization efforts for select modifiable risk factors.

Role of bariatric surgery in reducing periprosthetic joint infections in total knee arthroplasty. A systematic review and meta-analysis

BACKGROUND

Obesity represents an epidemic of rising numbers worldwide year after year. In the Orthopedic field, obesity is one of the major causes leading to osteoarthritis needing Total Joint Arthroplasty (TJA). Still, contextually, it represents one of the most significant risk factors for joint replacement complications and failures. So, bariatric Surgery (BS) is becoming a valuable option for weight control and mitigating obesity-related risk factors. This review of the literature and meta-analysis aims to evaluate periprosthetic joint infections (PJI) and surgical site infections (SSI) rates in patients who underwent TKA after BS compared to obese patients without BS.

METHODS

Systematic review was performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines up to October 2023. We included longitudinal studies comparing obese patients who underwent total knee arthroplasty after bariatric surgery (study group) and obese patients who underwent TKA (control group). The surgical site infection and Periprosthetic joint infection rate were compared among groups using a meta-analytical approach.

RESULTS

The online database and references investigation identified one hundred and twenty-five studies. PJI rate differed significantly among groups, (z = -21.8928, p < 0.0001), with a lower risk in the BS group (z = -10.3114, p < 0.0001), for SSI, instead, not statistically significance were recorded (z = -0.6784, p = 0.4975).

CONCLUSIONS

The current Literature suggests that Bariatric Surgery can reduce infectious complications in TKA, leading to better outcomes and less related costs treating of knee osteoarthritis in obese patients.

Robotic-Assisted Total Knee Arthroplasty in Obese Patients

Background

Robotic-assisted systems have gained popularity in total knee arthroplasty (TKA). The purpose of this study was to evaluate operative characteristics and radiographic outcomes of obese patients undergoing robotic-assisted TKA.

Methods

A retrospective review of consecutive cases performed by a single surgeon was performed from January 1, 2016, to January 31, 2022. Adult patients with body mass index ≥35 kg/m2 who underwent primary TKA using a computed tomography-assisted robotic system were compared to patients who underwent primary TKA using conventional instrumentation. Demographics, preoperative and postoperative radiographic measurements, and intraoperative outcomes were compared between cohorts. In total, 119 patients were identified, 60 in the robotic-assisted cohort and 59 in the conventional instrumentation cohort.

Results

Age, body mass index, and estimated blood loss were not significantly different between the cohorts. The robotic-assisted cohort experienced longer tourniquet times (93.3 vs 75.5 minutes, P < .001). Preoperative hip-knee-ankle angle (HKA) was similar between the robotic-assisted and conventional cohorts (8.4° ± 4.9° vs 9.3° ± 5.3°, P = .335). Postoperative HKA was 2.0° ± 1.4° in the robotic-assisted group and 3.1° ± 3.23° in the conventional group (P = .040). The proportion of patients with postoperative HKA > 3° of varus or valgus was 9 of 60 (15.0%) in the robotic-assisted cohort compared to 18 of 59 (30.5%) using conventional instrumentation (P = .043).

Conclusions

Obese patients treated with robotic-assisted TKA had postoperative alignment closer to neutral and fewer postoperative radiographic outliers than patients treated with conventional instrumentation. The results of this study support use of robotic-assisted technologies in TKA, particularly in obese patients.

Does the use of tibial stem extensions reduce the risk of aseptic loosening in obese patients undergoing primary total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

This study aimed to compare the risk of revision for aseptic loosening in obese (body mass index >30 kg/m2) patients with stemmed (ST) versus non-stemmed (NST) tibial implants in primary total knee arthroplasty (TKA).

METHODS

A systematic review and meta-analysis were conducted following PRISMA and MOOSE guidelines. Studies reporting a direct comparison between ST and NST tibial implants in obese patients were included. The primary outcome of interest was revision for aseptic loosening. Outcomes were analysed using meta-analysis of relative risk. Risk of bias assessment was performed using the Newcastle-Ottawa Scale for observational studies and the RoB-2 Cochrane tool for randomised studies.

RESULTS

Seven studies met the selection criteria, consisting of four cohort studies and three randomised controlled trials. Mean follow up time for the eligible cohort was 62.6 months. Meta-analysis demonstrated a statistically significant reduction in the risk of aseptic revision in the ST group compared with the NST group (risk ratio 0.25, 95% confidence interval 0.07 to 0.92). After removal of all zero-event studies, the results remained in favour of the ST group (risk ratio 0.15, 95% confidence interval 0.03 to 0.64).

CONCLUSIONS

This study found that obese patients undergoing TKA with stemmed tibial implants may have a lower risk of aseptic revision compared with those with non-stemmed tibial implants. However, due to the lack of high-quality literature available, our study is unable to draw a definitive conclusion on this matter. We suggest that this topic should be re-evaluated using higher-quality study methods, particularly national joint registries studies and randomised controlled trials.

One-Year Postoperative Patient-Reported Outcome Measures Are Associated With Three-Year to Five-Year Postoperative Satisfaction in Total Knee Arthroplasty

BACKGROUND

Over the past couple of decades, the definition of success after total knee arthroplasty (TKA) has shifted away from clinician-rated metrics and toward the patient's subjective experience. Therefore, understanding the aspects of patient recovery that drive 3-year to 5-year satisfaction after TKA is crucial. The aims of this study were to (1) determine the 1-year postoperative factors, specifically patient-reported outcome measures (PROMs) that were associated with 3-year and 5-year postoperative satisfaction and (2) understand the factors that drive those who are not satisfied at 1 year postoperatively to become satisfied later in the postoperative course.

METHODS

This was a retrospective study of 402 TKA patients who were gathered prospectively and presented for their 1-year follow-up. Demographics were collected preoperatively and patient-reported outcomes were collected at 1, 3, and 5 years postoperatively. Logistic regressions were used to identify the factors at 1 year that were associated with 3-year and 5-year satisfaction.

RESULTS

Associations between 1-year PROMs with 3-year satisfaction were observed. Longer term satisfaction at 5 years was more closely associated with EuroQol 5 Dimension Mobility, Activity Score, and Numerical Rating Scale Satisfaction. Of those who were not satisfied at 1 year, EuroQol 5 Dimension Mobility, Knee Disability Osteoarthritis Outcome Score Function in Sport and Recreation, and Satisfaction were associated with becoming satisfied at 3 years.

CONCLUSION

The 1-year PROMs were found to be associated with satisfaction at 3 to 5 years after TKA. Importantly, many of the PROMs that were associated with 3-year to 5-year satisfaction, especially in those who were not originally satisfied at 1 year, were focused on mobility and activity level.

The Effect of Obesity on Hemiarthroplasty and Total Hip Arthroplasty for Femoral Neck Fractures

Obesity is a well-recognized global epidemic that can lead to longer operative times as well as a greater technical demand. Despite this, the available literature evaluating the impact of obesity on hip hemiarthroplasty (HA) and total hip arthroplasty (THA) when treating fractures about the femoral neck is scarce. Between 2015 and 2018, we retrospectively reviewed all patients that had a HA or THA performed as treatment for an isolated fracture of the femoral neck. Patients were classified as obese and nonobese depending on current body mass index (BMI) when the index procedure was performed. Preoperative and postoperative variable were obtained from the electronic medical record. A total of 157 patients underwent hip HA or THA for an isolated fracture of the femoral neck. In those patients undergoing HA, obesity was associated with an increase in operative times (P = 0.021) and was associated with a nonsignificant increase in total operating room time (P = 0.088) and duration of anesthesia (P = 0.14). In those patients undergoing THA, obesity was associated with longer operative times (P = 0.043), total operating room time (P = 0.032), and duration of anesthesia (P = 0.045). There were no significant differences in complication rates postoperatively between obese and non-obese patients undergoing either procedure. The treatment of isolated fractures of the femoral neck with HA or THA leads to an increase in operative time without an increase in postoperative complications in obese patients.

Evolution of body mass index and complications rate in severely or morbidly obese patients undergoing total knee arthroplasty

INTRODUCTION

Associations between obesity and knee osteoarthritis or complications after total knee arthroplasty (TKA) are well established. The procedure can significantly improve knee function, favoring weight loss, despite the risk of surgical complications. The main objective of the present study was to assess change in body mass index (BMI) after TKA in patients with severe or morbid obesity (BMI≥35kg/m2). The secondary endpoint was the rate of surgical revision. The hypotheses were that there is no significant change in BMI after TKA and that there is a significant rate of revision.

METHODS

This retrospective descriptive study was conducted for the period June 2009 to December 2019. Thirty-three patients (48 knees) were included: 27 women, 6 men; mean age, 66.5 years (range, 55-80). Preoperatively, 11 patients had BMI 35-39.9kg/m2 and 22 BMI≥40 (including 11 with BMI≥45kg/m2). The preoperative axis was in varus for 35 patients (73%, including 54%≥10°) and in valgus for 13 (27% including 33%≥10°). Radiological and clinical evaluation was carried out at 3 months and 1 year postoperatively. At≥2 years, change in BMI and EQ5D functional score were established by telephone survey; >5% change in BMI was considered significant.

RESULTS

Mean follow-up was 6.9±2.3 years (range, 2.9-10.5). Twenty-five patients (38 knees) were included for analysis. Mean postoperative BMI was 41±5kg/m2, with a mean decrease of 1.2±3.6kg/m2. At the last follow-up, BMI had increased in 8 patients (32%), including 3 by >5% (12%), and decreased in 16 (64%), including 7 by >5% (28%). The higher the baseline BMI, the greater the decrease: for BMI [35-39.9], -0.81 (range, -6.8; +4.3); for BMI [40-44.5],-1 (range, -9; +5.22); and for BMI>45, -1.54 (range, -3.97; +1.3). EQ5D averaged 0.75 at last follow-up. The higher the preoperative BMI, the more satisfactory the postoperative EQ5D: EQ5D for BMI [35-39.9]=0.71 (range, 0.36; 1); for BMI [40-44.5]=0.75 (range, 0.45; 1); and for BMI>45=0.80 (range, 0.48; 1). Four early surgical site infections (10.5%) and 2 isolated changes of the tibial component for early loosening (5.2%) required surgical revision.

CONCLUSION

Patients with severe or morbid obesity had a low tendency to lose weight after TKA, but this does not appear to us to be clinically relevant: the functional results were good. Nevertheless, this series showed a significant rate of revision (15%). TKA was feasible in patients with BMI≥35kg/m2, but requires appropriate patient information.

LEVEL OF EVIDENCE

IV.

Morbidly Obese Patients Undergoing Unicompartmental Knee Arthroplasty Compared to Total Knee Arthroplasty: A Retrospective Case-Controlled Analysis

BACKGROUND

In this study, we assess the effects that morbid obesity (body mass index (BMI) ≥ 40) has on: (1) Ninety-day medical complications and readmission rates; (2) costs of care and lengths of stay (LOS); and (3) 2-year implant complications in patients undergoing unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA).

METHODS

A retrospective query of TKA and UKA patients were identified using a national database. Morbidly obese UKA patients were matched 1:5 to morbidly obese TKA patients by demographic and comorbidity profiles. Subgroup analyses were conducted using the same process between morbidly obese UKA patients and BMI <40 TKA patients, as well as to BMI <40 UKA patients.

RESULTS

Morbidly obese patients who underwent UKA had significantly fewer medical complications, readmissions, and periprosthetic joint infections than TKA patients; however, UKA patients had greater odds of mechanical loosening (ML). The TKA patients had significantly longer LOS (3.0 versus 2.4 days, P < .001), as well as significantly greater costs of care than UKA patients ($12,869 versus $7,105). Morbidly obese UKA patients had similar rates of medical complications, and significantly lower readmissions, decreased LOS, and decreased costs when compared to TKA patients who had a BMI <40.

CONCLUSION

In patients who have morbid obesity, complications were decreased in UKA compared to TKA. Moreover, morbidly obese UKA patients had lower medical utilizations and similar complication rates when compared to TKA patients with the recommended cutoff of BMI <40. However, UKA patients had greater rates of ML than TKA patients. A UKA may be an acceptable treatment option for unicompartmental osteoarthritis in morbidly obese patients.

Body Mass Index and Revision Total Knee Arthroplasty: Does Cause for Revision Vary by Underweight or Obese Status?

BACKGROUND

Body mass index (BMI) impacts risk for revision total knee arthroplasty (rTKA), but the relationship between BMI and cause for revision remains unclear. We hypothesized that patients in different BMI classes would have disparate risk for causes of rTKA.

METHODS

There were 171,856 patients who underwent rTKA from 2006 to 2020 from a national database. Patients were classified as underweight (BMI < 19), normal-weight, overweight/obese (BMI 25 to 39.9), or morbidly obese (BMI > 40). Multivariable logistic regressions adjusted for age, sex, race/ethnicity, socioeconomic status, payer status, hospital geographic setting, and comorbidities were used to examine the effect of BMI on risk for different rTKA causes.

RESULTS

Compared to normal-weight controls, underweight patients were 62% less likely to undergo revision due to aseptic loosening, 40% less likely due to mechanical complications, 187% more likely due to periprosthetic fracture, 135% more likely due to periprosthetic joint infection (PJI). Overweight/obese patients were 25% more likely to undergo revision due to aseptic loosening, 9% more likely due to mechanical complications, 17% less likely due to periprosthetic fracture, and 24% less likely due to PJI. Morbidly obese patients were 20% more likely to undergo revision due to aseptic loosening, 5% more likely due to mechanical complications, and 6% less likely due to PJI.

CONCLUSION

Mechanical reasons were more likely to be the cause of rTKA in overweight/obese and morbidly obese patients, compared to underweight patients, for whom revision was more likely to be infection or fracture related. Increased awareness of these differences may promote patient-specific management to reduce complications.

LEVEL OF EVIDENCE

III.

Obesity is Associated With Greater Improvement in Patient-Reported Outcomes Following Primary Total Knee Arthroplasty

BACKGROUND

Body mass index (BMI) cutoffs have been established for total knee arthroplasty (TKA) patients due to increased risk of medical complications in obese patients. However, evidence-based medical optimization may mitigate risk in these patients. This study examined the influence of BMI on patient-reported outcome measures (PROMs) following primary TKA with specialized perioperative optimization.

METHODS

Between 2016 and 2020, 1,329 consecutive primary TKAs using standardized perioperative optimization were retrospectively reviewed. Patients were categorized into ordinal groups based on BMI in 5 kg/m2 increments (range, 17 to 61). Primary outcomes related to activity level, pain, function, and satisfaction were evaluated. BMI groups ≥35 had significantly lower age, more women, and higher prevalence of comorbidities (P ≤ .004). Mean follow-up was 1.7 years (range, 1 to 5 years).

RESULTS

Each successive BMI group from 35 to ≥50 demonstrated continually greater improvement in pain with level walking and stair climbing (P ≤ .001), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (P = .001), and greater satisfaction (P = .007). No patients who had a BMI ≥35 were revised for aseptic loosening, and rates of periprosthetic joint infection were not different between BMI groups (P = 1.000).

CONCLUSION

Despite being more debilitated preoperatively, patients who had a BMI ≥35 experienced greater improvements in PROMs compared to patients who had lower BMI. Given the significant improvements in PROMs and quality of life in obese patients, with appropriate perioperative optimization, these patients should not be prohibited from having a TKA when appropriately indicated.

LEVEL OF EVIDENCE

III.

Is there an indication for simultaneous bilateral knee arthroplasty in morbidly obese patients? Should the patients' request for simultaneous operation be considered?

PURPOSE

This study aimed to analyse the safety of simultaneous bilateral total knee arthroplasty (SBTKA) surgery by comparing morbidly obese (MO) patients with obese patients.

METHODS

SBTKA was performed to 494 patients by a single surgeon in a single center between 2014-2020. The patients followed for a mean of 26 months. They were divided into two groups according to body mass index (BMI) as MO (BMI> 40 kg/m2, n = 65) and obese(O) (BMI = 30-39.9 kg/m2, n = 429 patients). The groups were compared in terms of wound healing problems (WHP), mobilization time (MT), operation time (OT), prosthesis infection, aseptic loosening (AL), early complications, revision, and length of hospitalization using univariate and multivariate logistic regression analyses.

RESULTS

Logistic regression analysis revealed significant differences in the clinical outcomes and complications between MO and O patients. Parameters such as length of stay, OT, MT, WHP, debridement, medial retinaculum detachment (MRD) and AL, and short-term complications such as acute kidney injury (AKI), and pulmonary embolism (PE) incidence were significantly higher in the MO group. Among the MO patients, the clinical outcomes were worse than those among the O patients, and the complication incidence was higher.

CONCLUSION

We do not find SBTKA surgery feasible in morbidly obese patients due to the high complication rate and unsatisfactory clinical outcomes. We suggest that the patient's request to undergo SBTKA should not be taken into account, and that staged surgery be preferred.

Stemmed Versus Nonstemmed Tibia in Primary Total Knee Arthroplasty: A Similar Pattern of Aseptic Tibial Loosening in Obese Patients with Moderate Varus. 5-Year Outcomes of a Randomized Controlled Trial

Obesity is linked to early tibial tray failure after primary total knee arthroplasty (TKA) for osteoarthritis (OA), especially in patients with preoperative varus. This study compared standard and stemmed tibiae TKAs in patients with class I and II obesity with varus deformity. Between April 2013 and June 2020, a prospective study was conducted including patients with end-stage OA, body mass index between 30 and 40 kg/m2, and varus <15 degrees. Patients were randomly assigned to TKAs with either standard or long-stemmed tibiae and evaluated 5 years after surgery using the Knee Society Scoring (KSS). The knee society and modified radiographic evaluation systems were used for radiological evaluation. In total, 264 TKAs were performed in 264 patients (134 in the standard group and 130 in the stemmed group). The mean preoperative hip-knee-ankle angles for the standard and stemmed groups were 8.2 ± 3.2 degrees/varus and 9 ± 2.9 degrees/varus, respectively (p = 0.2), which improved to 5.1 ± 3 degrees/valgus and 5 ± 3.5 degrees/valgus after surgery (p = 0.52). There was no statistically significant difference between the objective KSS (92 vs. 92.9; p = 0.84) and the functioning KSS (73.4 vs. 74.8; p = 0.28). There were no aseptic loosening cases or radiographic differences. In-group analysis revealed significant outcomes differences in both groups if preoperative varus was >10 degrees irrespective of the stem design (p < 0.0001). Complications occurred in two patients; one with a late infection and one had a stem-related tibial fracture. Standard tibia TKAs yielded comparable results in obese patients to long-stemmed tibias. No aseptic tibial loosening was observed regardless of stem type, and worse clinical outcomes were associated with greater varus. CLINICAL TRIAL REGISTRY::  registered at http://www.researchregistry.com (researchregistry5717).LEVEL OF EVIDENCE: II; a prospective randomized trial.

Is a Higher Number of Total Hip and Knee Arthroplasty Revisions Associated With Increased Mortality?

BACKGROUND

It remains uncertain whether patients who undergo numerous total hip arthroplasty (THA) and/or knee arthroplasty (TKA) revisions exhibit decreased survival. Therefore, we sought to determine if the number of revisions per patient was a mortality predictor.

METHODS

We retrospectively reviewed 978 consecutive THA and TKA revision patients from a single institution (from January 5, 2015-November 10, 2020). Dates of first-revision or single revision during study period and of latest follow-up or death were collected, and mortality was assessed. Number of revisions per patient and demographics corresponding to first revision or single revision were determined. Kaplan-Meier, univariate, and multivariate Cox-regressions were utilized to determine mortality predictors. The mean follow-up was 893 days (range, 3-2,658).

RESULTS

Mortality rates were 5.5% for the entire series, 5.0% among patients who only underwent TKA revision(s), 5.4% for only THA revision(s), and 17.2% for patients who underwent TKA and THA revisions (P = .019). In univariate Cox-regression, number of revisions per patient was not predictive of mortality in any of the groups analyzed. Age, body mass index (BMI), and American Society of Anesthesiologists (ASA) were significant mortality predictors in the entire series. Every 1 year of age increase significantly elevated expected death by 5.6% while per unit increase in BMI decreased the expected death by 6.7%, ASA-3 or ASA-4 patients had a 3.1 -fold increased expected death compared to ASA-1 or ASA-2 patients.

CONCLUSION

The number of revisions a patient underwent did not significantly impact mortality. Increased age and ASA were positively associated with mortality but higher BMI was negatively associated. If health status is appropriate, patients can undergo multiple revisions without risk of decreased survival.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Improving Patient Access to Musculoskeletal Care

Preoperative optimization programs for total joint arthroplasty identify and address risk factors to reduce postoperative complications, thereby improving patients' ability to be safe surgical candidates. This article introduces preoperative optimization programs and describes the role of orthopaedic nurse navigators. This foundation will be used to produce an article series with recommendations for optimization of several modifiable biopsychosocial factors. We consulted orthopaedic nurse navigators across the United States and conducted a literature review regarding preoperative optimization to establish the importance of nurse navigation in preoperative optimization. The responsibilities of nurse navigators, cited resources, and structure of preoperative optimization programs varied among institutions. Optimization programs relying on nurse navigators frequently demonstrated improved outcomes. Our discussions and literature review demonstrated the integral role of nurse navigators in preoperative optimization. We will discuss specific risk factors and how nurse navigators can manage them throughout this article series.

Using Presurgical Biopsychosocial Features to Develop an Advanced Clinical Decision-Making Support Tool for Predicting Recovery Trajectories in Patients Undergoing Total Knee Arthroplasty: Protocol for a Prospective Observational Study

BACKGROUND

Following total knee arthroplasty (TKA), 10% to 20% of patients report dissatisfaction with procedural outcomes. There is growing recognition that postsurgical satisfaction is shaped not only by the quality of surgery but also by psychological and social factors. Surprisingly, information on the psychological and social determinants of surgical outcomes is rarely collected before surgery. A comprehensive collection of biopsychosocial information could assist clinicians in making recommendations in relation to rehabilitation, particularly if there is robust evidence to support the ability of presurgical constructs to predict postsurgical outcomes. Clinical decision support tools can help identify factors influencing patient outcomes and support the provision of interventions or services that can be tailored to meet individuals' needs. However, despite their potential clinical benefit, the application of such tools remains limited.

OBJECTIVE

This study aims to develop a clinical decision tool that will assist with patient stratification and more precisely targeted clinical decision-making regarding prehabilitation and rehabilitation for TKA, based on the identified individual biopsychosocial needs.

METHODS

In this prospective observational study, all participants provided written or electronic consent before study commencement. Patient-completed questionnaires captured information related to a broad range of biopsychosocial parameters during the month preceding TKA. These included demographic factors (sex, age, and rurality), psychological factors (mood status, pain catastrophizing, resilience, and committed action), quality of life, social support, lifestyle factors, and knee symptoms. Physical measures assessing mobility, balance, and functional lower body strength were performed via video calls with patients in their home. Information related to preexisting health issues and concomitant medications was derived from hospital medical records. Patient recovery outcomes were assessed 3 months after the surgical procedure and included quality of life, patient-reported knee symptoms, satisfaction with the surgical procedure, and mood status. Machine learning data analysis techniques will be applied to determine which presurgery parameters have the strongest power for predicting patient recovery following total knee replacement. On the basis of these analyses, a predictive model will be developed. Predictive models will undergo internal validation, and Bayesian analysis will be applied to provide additional metrics regarding prediction accuracy.

RESULTS

Patient recruitment and data collection commenced in November 2019 and was completed in June 2022. A total of 1050 patients who underwent TKA were enrolled in this study.

CONCLUSIONS

Our findings will facilitate the development of the first comprehensive biopsychosocial prediction tool, which has the potential to objectively predict a patient's individual recovery outcomes following TKA once selected by an orthopedic surgeon to undergo TKA. If successful, the tool could also inform the evolution rehabilitation services, such that factors in addition to physical performance can be addressed and have the potential to further enhance patient recovery and satisfaction.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/48801.

The Impact of Metabolic Syndrome and Obesity on Perioperative Total Joint Arthroplasty Outcomes: The Obesity Paradox and Risk Assessment in Total Joint Arthroplasty

Background

The relationship between elevated body mass index (BMI) and adverse outcomes in joint arthroplasty is well established in the literature. This paper aims to challenge the conventional thought of excluding patients from a total knee or hip replacement based on BMI alone. Instead, we propose using the metabolic syndrome (MetS) and its defining components to better identify patients at high risk for intraoperative and postoperative complications.

Methods

Patients who underwent primary, elective total knee and total hip arthroplasty were identified in the 2015-2020 American College of Surgeons National Surgical Quality Improvement Program database. Several defining components of MetS, such as hypertension, diabetes, and obesity, were compared to a metabolically healthy cohort. Postoperative outcomes assessed included mortality, length of hospital stay, 30-day surgical and medical complications, and discharge.

Results

The outcomes of 529,737 patients from the American College of Surgeons National Surgical Quality Improvement Program who underwent total knee and total hip arthroplasty were assessed. MetS is associated with increased complications and increased mortality. Both hypertension and diabetes are associated with increased complications but have no impact on mortality. Interestingly, while obesity was associated with increased complications, there was a significant decrease in mortality.

Conclusions

Our results show that the impact of MetS is more than the sum of its constitutive parts. Additionally, obese patients experience a protective effect, with lower mortality than their nonobese counterparts. This study supports moving away from strict BMI cutoffs alone for someone to be eligible for an arthroplasty surgery and offers more granular data for risk stratification and patient selection.

Medication use and comorbidities in an increasingly younger osteoarthritis population: an 18-year retrospective open-cohort study

OBJECTIVES

As understanding of the pathogenesis and treatment strategies for osteoarthritis (OA) evolves, it is important to understand how patient factors are also changing. Our goal was to examine demographics and known risk factors of patients with OA over time.

DESIGN

Open-cohort retrospective study using electronic health records.

SETTING

Large US integrated health system with 7 hospitals, 2.6 million outpatient clinic visits and 97 300 hospital admissions annually in a mostly rural geographic region.

PARTICIPANTS

Adult patients with at least two encounters and a diagnosis of OA or OA-relevant surgery between 2001 and 2018. Because of geographic region, over 96% of participants were white/Caucasian.

INTERVENTIONS

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

Descriptive statistics were used to examine age, sex, body mass index (BMI), Charlson Comorbidity Index, major comorbidities and OA-relevant prescribing over time.

RESULTS

We identified 290 897 patients with OA. Prevalence of OA increased significantly from 6.7% to 33.5% and incidence increased 37% (from 3772 to 5142 new cases per 100 000 patients per year) (p<0.0001). Percentage of females declined from 65.3% to 60.8%, and percentage of patients with OA in the youngest age bracket (18-45 years) increased significantly (6.2% to 22.7%, p<0.0001). The percentage of patients with OA with BMI ≥30 remained above 50% over the time period. Patients had low comorbidity overall, but anxiety, depression and gastro-oesophageal reflux disease showed the largest increases in prevalence. Opioid use (tramadol and non-tramadol) showed peaks followed by declines, while most other medications increased slightly in use or remained steady.

CONCLUSIONS

We observe increasing OA prevalence and a greater proportion of younger patients over time. With better understanding of how characteristics of patients with OA are changing over time, we can develop better approaches for managing disease burden in the future.

Screening and Management of Malnutrition in Total Joint Arthroplasty

Malnutrition is an increasingly prevalent problem in patients undergoing total joint arthroplasty (TJA). Increased risks associated with TJA in the setting of malnourishment have been well documented. Standardized scoring systems in addition to laboratory parameters such as albumin, prealbumin, transferrin, and total lymphocyte count have been developed to identify and evaluate malnourished patients. Despite an abundance of recent literature, there is no consensus on the best approach for screening TJA patients from a nutritional standpoint. Although there are a variety of treatment options, including nutritional supplements, nonsurgical weight loss therapies, bariatric surgery, and the involvement of dieticians and nutritionists, the effect of these interventions on TJA outcomes has not been well characterized. This overview of the most current literature aims to provide a clinical framework for approaching nutrition status in arthroplasty patients. A comprehensive understanding of the tools available for managing malnourishment will facilitate improved arthroplasty care.

The effects of hypoalbuminemia in obese patients undergoing total joint arthroplasty

INTRODUCTION

Total joint arthroplasty (TJA) is a highly effective surgery. However, poor nutritional status has been associated with worse outcomes. In orthopedics, nutrition status is commonly evaluated using serum albumin. When albumin levels fall below 3.0 g/dL, wound healing ability becomes impaired. Typically, malnutrition is associated with low BMI, but malnourished patients can also be obese. The goals of this study were to investigate the relationship between malnourishment represented through albumin levels of obese patients and likelihood of postoperative complications.

METHODS

A retrospective review of patients undergoing primary TJA from 2016 to 2020 in the American College of Surgeons National Surgical Quality Improvement Program national database was performed. Patients with an albumin of < 3.5 g/dL were considered to have hypoalbuminemia and those with ≥ 3.5 g/dL were considered normal albumin. Univariate analysis was used to determine demographic and comorbidity differences between those with and without hypoalbuminemia. Outcomes of interest included length of stay, resource utilization, discharge disposition, and unplanned readmissions. Multivariate logistic regression examined albumin as a predictor of increased resource utilization and complications after controlling for possible confounding variables.

RESULTS

Of the 79,784 patients, 4.96% of patients had low albumin. Those with hypoalbuminemia were nearly 1.5 years older than those with normal albumin, were more likely to be black, female, and had an overall increased comorbidity burden as shown by percent of patients with ASA > 3 (all p < 0.001). After risk adjustment, those with hypoalbuminemia and a BMI of 35 + had greater risk of complications and increased resource utilization.

CONCLUSION

Our results demonstrated the prevalence of malnutrition increases as a patient's BMI increases. Further, hypoalbuminemia was associated with increased resource utilization and increased complication rates in all obese patients. We suggest screening albumin levels in obese patients preoperatively to give surgeons the best opportunity to optimize patient nutrition before undergoing surgery.

Temporal trends in the rate of complications and prolonged length of stay relative to body mass index in patients undergoing total knee arthroplasty from 2012 to 2020

BACKGROUND

Elevated body mass index (BMI) is a risk factor for complications following total knee arthroplasty (TKA). Thus, we believe it is important to constantly re-evaluate the relationship between BMI and complication risk following TKA.

METHOD

Patients undergoing primary TKA were identified in a national database from 2012-2020. Rates of major complications, minor complications, and length of stay (LOS) greater than 2 days were calculated. The prevalence of postoperative outcomes were calculated per unit of BMI and then multiplied by a factor of 10^{^2} or 10^{^3} in order to create adjusted-BMI (aBMI). To isolate the effect of aBMI on postoperative outcomes, changes over time were analyzed using linear regression analysis controlling for age, sex, American Society of Anesthesiology (ASA) classification and smoking status.

RESULTS

365,333 patients were included. Mean BMI 33 ± 6.8. 10,616 (2.9%) of patients had a major postoperative complication, 9,345 (2.6%) minor complications, 3,277 (0.9%) had a deep or superficial surgical site infection (SSI). 133,563 (37%) of patients had LOS > 2 days. From 2012-2020, the ratio of major complications to aBMI decreased significantly by an average of -2.7% per year. The ratio of patients with LOS > 2 days to aBMI decreased significantly by -27% per year. The ratio of SSI to aBMI increased significantly by 10.8% per year.

CONCLUSIONS

From 2012 to 2020, the ratio of major complications and extended LOS following TKA as a function of BMI has decreased significantly, while the ratio of SSI as a function of BMI has doubled.

Obesity and total joint arthroplasty: Does weight loss in the preoperative period improve perioperative outcomes?

Background

The obese population is more likely to develop degenerative joint disease requiring total joint arthroplasty (TJA) and also experience increased rates of adverse post-surgical outcomes. This study assessed whether a quantifiable weight loss prior to TJA had any impact on perioperative and 30-day outcomes in obese patients.

Method

Using the American College of Surgeons-National Surgical Quality Improvement Program database, obese patients who underwent total hip or total knee arthroplasty and lost at least 10% of their total body weight prior to surgery were identified and matched to other obese individuals undergoing the same procedures without weight loss. Perioperative outcomes, including operative time, length of stay, discharge destination, or 30-day adverse events, including complications, re-admissions, re-operations, and mortality, were then compared using conditional Logistic regression analysis.

Results

Analysis showed no difference between the two groups in terms of operative time, length of stay, discharge destination, or 30-day adverse events, including complications, re-admissions, re-operations, and mortality.

Conclusion

The results of this study suggest that weight loss alone in the preoperative period may not be sufficient to mitigate the effects of obesity on immediate post-TJA outcomes.

Movement Is Life-Optimizing Patient Access to Total Joint Arthroplasty: Obesity Disparities

Thirty five percent of the American population is considered obese (body mass index [BMI] > 30). Obesity disproportionately affects African Americans, Hispanics, and women. Obesity is associated with postoperative complications, including wound complications, infections, and revision total joint arthroplasty (including total hip arthroplasty and total knee arthroplasty). Current BMI benchmarks (many institutions rely on a BMI of 40) selectively preclude patients from having surgery. Patients in these underserved populations can be optimized through the lens of shared decision making through the assessment of food security (eg, food deserts and food swamps), ability to afford healthy food, knowledge of social safety net and community resources to access healthy food, nutrition and weight loss referrals to programs that accept all forms of insurance, weight loss measurements as a percentage of body weight lost instead of BMI cutoffs, pharmacologic modalities, and bariatric surgery.

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

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

The impact of obesity on total knee arthroplasty outcomes: A retrospective matched cohort study

Background

Total Knee Arthroplasty (TKA) is a common orthopaedic surgery to treat advanced knee arthritis. Post-operative complications can be affected by obesity, defined as a body mass index of 30 kg/m2 or higher. We examine the rates of specific complications, revision rates, and costs of care following TKA and compare them between multifactor matched obese and non-obese patients. We hypothesize these outcomes will be worse in obese patients than in non-obese patients.

Methods

This retrospective study of the PearlDiver database queries for patients who underwent TKA under Current Procedural Terminology (CPT) and International Statistical Classification of Diseases (ICD-9) codes between January 2011 and January 2020. Patients were matched based on age, gender, and comorbidity indices, and various complications, revision rates, and costs were compared between the matched obese and non-obese patient groups.

Results

Obesity was associated with higher rates of surgical complications, such as wound complications, surgical site infections, need for revision, and higher total cost of care one year after TKA, and medical complications such as, acute kidney injury, deep vein thrombosis, urinary tract infection, and narcotics use, but significantly lower rates of anemia, arrhythmia, cardiac arrest, pneumonia, and transfusion. Obese patients also experienced significantly lower drug costs of care.

Conclusion

Outcomes were not definitively worse in obese patients when compared to matched non-obese patients. Nevertheless, understanding the complications that can arise following TKA will assist in educating patients about potential risks from surgery and guide surgeons in caring for their patients as obesity is predicted to continue increasing in prevalence. As such, future studies should examine underlying mechanisms that cause these complications to develop potential therapies.

Does bariatric surgery really benefit patients before total knee arthroplasty? A systematic review and meta-analysis

PURPOSE

At present, whether bariatric surgery before total knee arthroplasty (TKA) affects the prognosis of subsequent TKA has been a topic of debate in the academic community. The primary purpose of this systematic review and meta-analysis was to investigate the effect of previous bariatric surgery on prosthetic revisions and postoperative complications after TKA.

METHODS

We included prospective and observational studies published in English involving patients who had undergone bariatric surgery prior to TKA and compared them with morbidly obese patients with no history of bariatric surgery. The Newcastle-Ottawa Scale was used to assess the methodological quality of non-randomized case-control studies. The outcomes included revisions, infections, venous thromboembolism (VTE), blood transfusion, mortality, stiffness or manipulation under anesthesia (MUA), and medical complications.

RESULTS

Of the 9 included studies with 166047 patients, 4 were matched cohort studies, 2 were unmatched cohort, and 3 were database studies. Methodological quality was high in ten studies and moderate in thirteen studies. Our analysis demonstrated that patients with TKA who had undergone prior bariatric surgery were associated with increased risks of long-term revision, long-term infection, long-term stiffness or MUA and blood transfusions, whereas prior bariatric surgery did not increase the risk of short-term complications and short-term revision.

CONCLUSION

This meta-analysis highlights the risks of bariatric surgery prior to TKA and suggests that prior bariatric surgery may increase the risk of perioperative blood transfusion and also the risk of revision and infection in long-term follow-up. Surgeons can use this information to help counsel patients undergoing bariatric surgery before primary TKA.

Effect of body mass index on symptomatic venous thromboembolism and prosthesis revision risk after total knee arthroplasty: a long-term study from China

OBJECTIVE

To investigate the effect of body mass index (BMI) on the risk of symptomatic VTE and prosthesis revision after total knee arthroplasty (TKA).

METHODS

Seven thousand one hundred eighty-two patients with primary unilateral TKA treated in our hospital from 2011 to 2020 were divided into four groups according to BMI: BMI < 25 kg/m², BMI 25 kg/m²-29.9 kg/m², BMI 30 kg/m²-34.9 kg/m² and BMI ≥ 35 kg/m². Incidence, Odds ratio and Kaplan-Meier survival analysis were used to evaluate the effects of BMI on symptomatic VTE and prosthesis revision risk after TKA.

RESULTS

The incidence of VTE after TKA was 8.9‰(64/7182). There was no significant difference in the incidence of VTE among different BMI groups(P = 0.452). Deep vein thrombosis mainly occurred in the distal lower extremities, especially in intermuscular veins. Revision rate of prosthesis after TKA was 6.4‰(46/7182). There was no significant difference in revision rate among different BMI groups(P = 0.718). In the univariate analysis of TKA, compared with patients with normal BMI, the risk of postoperative VTE and prosthesis revision in patients with overweight, obesity class I and obesity class II did not increase. Higher prosthesis revision rate and lower prosthesis survival rate were observed in BMI ≥ 35 kg/m² group, although the difference was not statistically significant.

CONCLUSIONS

Through such a retrospective large sample data of long-term follow-up, we believe that the higher BMI was not associated with the increased risk of symptomatic VTE and prosthesis revision after TKA. When TKA was used for appropriate indications, high BMI should not be considered as a contraindication.

The Extent Hospital Organizational Factors Influence Inpatient Care Delivery: A Case Study Looking at Knee and Hip Replacement Surgery

There is a body of Implementation and Dissemination research describing the importance of “context”—the characteristics describing the setting where a process or innovation occurs—when evaluating delivery, outcomes and cost of health services. These contextual factors, which can occur at the system, organization, or provider level, may either facilitate or erect barriers to the utilization of evidence-based practices and the outcomes achieved. This paper examines the influence of organizational structure and operating environment characteristics of where inpatient health care is delivered, controlling for patient and provider characteristics, on health services delivery and outcomes achieved. We used inpatient cost-of-care to represent the bundle of services provided to patients receiving primary knee and hip replacement procedures. Data includes patient level data from discharge records for 62 140 knee replacements and 42 392 hip replacements from the 2015 AHRQ Healthcare Cost and Utilization Project State Inpatient Discharge database and hospital characteristics from the 2015 American Hospital Association survey. Multi-level linear estimation models controlling for patient and payer characteristics were employed to assess the impact of specific organizational and operating environment factors. We found that although patient and payer characteristics significantly impacted the inpatient cost of care, there is significant variation between hospitals and among physicians within a hospital beyond what can be explained by patient, payer and local price effect characteristics. Organizational and physician characteristics that had the most significant impact on cost of care included the volume of services provided, urban location, and for-profit ownership. These factors can inform future policy and program design and evaluation.

Frank Stinchfield Award: Does Bariatric Surgery Prior to Primary Total Hip Arthroplasty Really Improve Outcomes?

BACKGROUND

Optimal management of morbid obesity before total hip arthroplasty (THA) remains debated. Recently, bariatric procedures have become more common with advancements in surgical techniques. We hypothesized that bariatric surgery prior to primary THA would mitigate acute postoperative complications and improve implant survivorship.

METHODS

A retrospective review from 1995 to 2020 identified 88 primary THA procedures in 71 unique patients who previously underwent bariatric surgery (73% Roux-en-Y). This cohort was matched 1:1:1 for age, gender, surgical year, American Society of Anesthesiologists score, and Charlson Comorbidity Index to cohorts of patients with body mass index (BMI) <40 kg/m² and BMI ≥40 kg/m². Revisions, reoperations, and acute complications were compared. Subgroup analysis then evaluated historical (pre-2012) relative to contemporary (2012 and after) bariatric procedures.

RESULTS

Revision rates for bariatric patients were higher relative to controls with low (hazard ratio [HR] 19, P < .01) and high BMI (HR 8, P < .01). Reoperation rates showed a similar increase for bariatric patients when compared to low (HR 9, P < .01) and high BMI (HR 4, P = .01) patients. Moreover, bariatric patients had an increased dislocation risk compared to the low (HR 7, P = .03) and high BMI (HR 17, P < .01) patients. Contemporary bariatric techniques had similar complications, revisions, and reoperations relative to historical procedures.

CONCLUSION

Morbidly obese patients undergoing THA have increased risks of certain complications, but it is unclear if bariatric surgery improves this risk. This study found that patients undergoing bariatric surgery have worse implant survivorship and higher dislocation rates compared to patients with naturally low and high BMIs. Further investigation into the post-bariatric metabolic state is warranted.

LEVEL OF EVIDENCE

Prognostic Level IV.

Does Bariatric Surgery Prior to Primary Total Knee Arthroplasty Improve Outcomes?

BACKGROUND

Recent advancements in bariatric surgical techniques have increased its utilization for the management of morbid obesity prior to total knee arthroplasty (TKA). We hypothesized that bariatric surgery prior to primary TKA would mitigate postoperative complications and improve implant survivorship.

METHODS

A retrospective review from 1992-2020 identified 205 bariatric surgery patients with subsequent primary TKA. This cohort was matched 1:1:1 to patients without bariatric surgery and with BMI <40 kg/m² and BMI ≥40 kg/m². Revisions, reoperations, and 90-day complications were evaluated. Subgroup analysis evaluated bariatric patients with BMI >40 kg/m² at TKA, the time between surgeries, and compared historical to contemporary bariatric techniques.

RESULTS

Bariatric patients demonstrated higher revision rates than low (HR 4, P < .01) and high BMI (HR 9, P < .01) controls, and increased reoperations when compared to the low (HR 2, P < .01) and high BMI (HR 6, P < .01) groups. Reoperation for instability was more common in bariatric patients than low (HR 15, P = .01) and high BMI (HR 17, P < .01) groups. Reoperation for infection was higher in bariatric patients relative to the high BMI (HR 6, P = .03), but not the low BMI cohort (HR 3, P = .06). There was no difference in 90-day complications (P = .33). Bariatric patients with high BMI and contemporary bariatric procedures did not significantly impact complications or survivorship, but bariatric surgery >2 years before TKA was associated with higher revision rates (P = .01).

CONCLUSION

This study found that bariatric surgery patients who undergo primary TKA have worse implant survivorship, mostly related to infection and instability. Further investigation into perioperative optimization is warranted.

LEVEL OF EVIDENCE

Prognostic Level IV.

The associations of implant and patient factors with migration of the tibial component differ by sex : a radiostereometric study on more than 400 total knee arthroplasties

AIMS

Thresholds of acceptable early migration of the components in total knee arthroplasty (TKA) have traditionally ignored the effects of patient and implant factors that may influence migration. The aim of this study was to determine which of these factors are associated with overall longitudinal migration of well-fixed tibial components following TKA.

METHODS

Radiostereometric analysis (RSA) data over a two-year period were available for 419 successful primary TKAs (267 cemented and 152 uncemented in 257 female and 162 male patients). Longitudinal analysis of data using marginal models was performed to examine the associations of patient factors (age, sex, BMI, smoking status) and implant factors (cemented or uncemented, the size of the implant) with maximum total point motion (MTPM) migration. Analyses were also performed on subgroups based on sex and fixation.

RESULTS

In the overall group, only fixation was significantly associated with migration (p < 0.001). For uncemented tibial components in males, smoking was significantly associated with lower migration (p = 0.030) and BMI approached significance (p = 0.061). For females with uncemented components, smoking (p = 0.081) and age (p = 0.063) approached significance and were both associated with increased migration. The small number of self-reported smokers in this study warrants cautious interpretation and further investigation. For cemented components in females, larger sizes of tibial component were significantly associated with increased migration (p = 0.004). No factors were significant for cemented components in males.

CONCLUSION

The migration of uncemented tibial components was more sensitive to patient factors than cemented implants. These differences were not consistent by sex, suggesting that it may be of value to evaluate female and male patients separately following TKA. Cite this article: Bone Joint J 2022;104-B(4):444-451.

Total knee arthroplasty in patients with severe obesity provides value for money despite increased complications

AIMS

Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m²). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m² to examine whether this is supported.

METHODS

This single-centre study compared 169 consecutive patients with severe obesity (BMI ≥ 40 kg/m²) (mean age 65.2 years (40 to 87); mean BMI 44.2 kg/m² (40 to 66); 129/169 female) undergoing unilateral TKA to a propensity score matched (age, sex, preoperative Oxford Knee Score (OKS)) cohort with a BMI < 40 kg/m² in a 1:1 ratio. Demographic data, comorbidities, and complications to one year were recorded. Preoperative and one-year patient-reported outcome measures (PROMs) were completed: EuroQol five-dimension three-level questionnaire (EQ-5D-3L), OKS, pain, and satisfaction. Using national life expectancy data with obesity correction and the 2020 NHS National Tariff, QALYs (discounted at 3.5%), and direct medical costs accrued over a patient's lifetime, were calculated. Probabilistic sensitivity analysis (PSA) was used to model variation in cost/QALY for each cohort across 1,000 simulations.

RESULTS

All PROMs improved significantly (p < 0.05) in both groups without differences between groups. Early complications were higher in BMI ≥ 40 kg/m²: 34/169 versus 52/169 (p = 0.050). A total of 16 (9.5%) patients with a BMI ≥ 40 kg/m² were readmitted within one year with six reoperations (3.6%) including three (1.2%) revisions for infection. Assuming reduced life expectancy in severe obesity and revision costs, TKA in patients with a BMI ≥ 40 kg/m² costs a mean of £1,013/QALY (95% confidence interval £678 to 1,409) more over a lifetime than TKA in patients with BMI < 40 kg/m². In PSA replicates, the maximum cost/QALY was £3,921 in patients with a BMI < 40 kg/m² and £5,275 in patients with a BMI ≥ 40 kg/m².

CONCLUSION

Higher complication rates following TKA in severely obese patients result in a lifetime cost/QALY that is £1,013 greater than that for patients with BMI < 40 kg/m², suggesting that TKA remains a cost-effective use of healthcare resources in severely obese patients where the surgeon considers it appropriate. Cite this article: Bone Joint J 2022;104-B(4):452-463.

The effect of BMI on the mid-term clinical outcomes of mobile-bearing unicompartmental knee arthroplasty

Objective

To evaluate the impact of body mass index (BMI) on the mid-term clinical outcomes and survival in patients receiving a mobile-bearing unicompartmental knee arthroplasty (UKA).

Methods

We retrospectively collected data from 355 patients who underwent UKA from June 2006 to June 2015, with a mean follow-up of 106.5 ± 22.5 months. Patients were assigned into four groups based on their BMI before surgery: normal weight group (BMI 18.5 ~ 22.9 kg/m²), overweight group (23 ~ 24.9 kg/m²), obesity group (25 ~ 29.9 kg/m²), and severe obesity group (≥ 30 kg/m²). The knee society score (KSS), knee society function score (KSFS), hospital for special surgery score (HSS), and range of motion (ROM) were assessed before the operation and at the last follow-up. The femorotibial angle (FTA) was assessed after the operation immediately and at the last follow-up. Kaplan–Meier survival analysis was performed among the four groups.

Results

The KSS, KSFS, and HSS in all groups were markedly improved compared with the preoperative values (p<0.001), but the ROM score was not significantly different (p>0.05). There were significant differences in KSS (p<0.001) and HSS (p = 0.004) across the four BMI groups, and these differences were due to the severe obesity group. All groups exhibited an inclination of knee varus deformity at the last follow-up (p < 0.05). Moreover, no marked difference in the implant survival rate was found among the different groups (p = 0.248), or in the survival curves (p = 0.593).

Conclusions

BMI does not influence the implant survival rate. The postoperative functional and quality-of-life scores were significantly improved in all groups. Obese (BMI ≥30 kg/m²) individuals should not be excluded from UKA.

Obesity, preoperative weight loss, and telemedicine before total joint arthroplasty: a review

The preoperative period prior to elective total joint arthroplasty (TJA) is a critical time for lifestyle interventions since a scheduled surgery may help motivate patients to lose weight. Weight loss may reduce complications associated with obesity following TJA and enable patients with severe obesity (body mass index [BMI] > 40 kg/m²) to become eligible for TJA, as many institutions use a 40 kg/m² cut-off for offering surgery. A comprehensive review was conducted to (1) provide background on complications associated with obesity following TJA, (2) synthesize prior research on the success rate of patients losing weight after being denied TJA for severe obesity, (3) discuss bariatric surgery before TJA, and (4) propose mobile health telemedicine weight loss interventions as potential weight loss methods for patients preoperatively. It is well established that obesity increases complications associated with TJA. In total knee arthroplasty (TKA), obesity increases operative time, length of stay, and hospitalization costs as well as the risk of deep infection, revision, and component malpositioning. Obesity may have an even larger impact on complications associated with total hip arthroplasty (THA), including wound complications and deep infection. Obesity also increases the risk of hip dislocation, aseptic loosening, and venous thromboembolism after THA. Synthesis of the only two studies (n = 417), to our knowledge, that followed patients denied TJA for severe obesity demonstrated that only 7% successfully reduced their BMI below 40 kg/m² via lifestyle modifications and ultimately underwent TJA. Unfortunately, bariatric surgery may only increase certain post-TKA complications including death, pneumonia, and implant failure, and there is limited research on preoperative weight loss via lifestyle modification. A review of short-term mobile health weight loss interventions that combined personalized counseling with self-monitoring via a smartphone app found about 5 kg of weight loss over 3-6 months. Patients with severe obesity have more weight to lose and may have additional motivation to do so before TJA, so weight loss results may differ by patient population. Research is needed to determine whether preoperative mobile health interventions can help patients become eligible for TJA and produce clinically significant weight loss sufficient to improve postoperative outcomes.

The BTK Safety Score: A Novel Scoring System for Risk Stratifying Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty

Selection of appropriate candidates for simultaneous bilateral total knee arthroplasty (si-BTKA) is crucial for minimizing postoperative complications. The aim of this study was to develop a scoring system for identifying patients who may be appropriate for si-BTKA. Patients who underwent si-BTKA were identified in the National Surgical Quality Improvement Program database. Patients who experienced a major 30-day complication were identified as high-risk patients for si-BTKA who potentially would have benefitted from staged bilateral total knee arthroplasty. Major complications included deep wound infection, pneumonia, renal insufficiency or failure, cerebrovascular accident, cardiac arrest, myocardial infarction, pulmonary embolism, sepsis, or death. The predictive model was trained using randomly split 70% of the dataset and validated on the remaining 30%. The scoring system was compared against the American Society of Anesthesiologists (ASA) score, the Charlson Comorbidity Index (CCI), and legacy risk-stratification measures, using area under the curve (AUC) statistic. Total 4,630 patients undergoing si-BTKA were included in our cohort. In our model, patients are assigned points based on the following risk factors: +1 for age ≥ 75, +2 for age ≥ 82, +1 for body mass index (BMI) ≥ 34, +2 for BMI ≥ 42, +1 for hypertension requiring medication, +1 for pulmonary disease (chronic obstructive pulmonary disease or dyspnea), and +3 for end-stage renal disease. The scoring system exhibited an AUC of 0.816, which was significantly higher than the AUC of ASA (0.545; p < 0.001) and CCI (0.599; p < 0.001). The BTK Safety Score developed and validated in our study can be used by surgeons and perioperative teams to risk stratify patients undergoing si-BTKA. Future work is needed to assess this scoring system's ability to predict long-term functional outcomes.

Body Composition Changes in the Immediate Peri-operative Period Following Total Joint Arthroplasty

BACKGROUND

Bioimpedance analysis (BIA) is a readily available tool to assess body composition in a clinical setting. BIA has received little attention in orthopaedics and namely joint arthroplasty. This study aims to quantify changes in body composition in the immediate peri-operative period following total joint arthroplasty.

METHODS

Adults scheduled for elective total joint arthroplasty were recruited to participate. Patients underwent BIA scans in the immediate peri-operative period: pre-operative on their day of surgery, post-operative day 0, and post-operative day 1.

RESULTS

67 patients were enrolled to undergo BIA scans. Mean age was 62.64 ± 10.28 years old, and 49.2% were females. The all-supine cohort exhibited a 0.36 ± 0.61 kg increase in dry lean mass (p < 0.001) and 1.30 ± 2.14 kg increase in lean body mass on postoperative day 0 (p < 0.001). Patients received to 1.16 ± 0.58 kg of fluid mass, on average.

CONCLUSION

BIA is a rapid, portable tool that allows for body composition analysis of an inpatient surgical population. This study demonstrated that BIA can detect net fluid changes and may approximate implant mass following total joint arthroplasty. This may aid surgeons in interpreting post-operative body composition changes.

Outcomes of Total Joint Arthroplasty in Black, Asian, Minority Ethnic Groups Versus Local Population: A Retrospective Review

BACKGROUND

 Total hip and knee replacement decrease the disability caused by osteoarthritis of the lower extremities. Although it has been established that racial and ethnic minorities underutilize these procedures, little data on postoperative outcomes exists. The impact of race on postoperative Oxford scores and complications following total joint arthroplasty (TJA) will be investigated in this retrospective review.

METHODS

 A retrospective review of 120 elective primary TJA procedures was undertaken between January 2016 and December 2019 in a single institution. To measure variations between the various groups, t-tests were used on their Oxford scores, and chi-squared bivariate regression was used to classify all categorical variables and the association of ethnicity and surgery type with gender.

RESULTS

 There were 62 (51.6%) White patients and 59 (49.1.0%) Black, Asian, Minority Ethnic (BAME) patients in total. The majority of the patients were females (60.9% vs 39.2%, p = 0.032). Low vitamin D levels were seen in a small percentage of patients in the sample (15.8% vs 84.2%, p = 0.460). There is a statistically important connection (p = 0.001) between the surgery type (total knee replacement [TKR]/total hip replacement [THR]) and gender; 41 females had TKR surgery, and 32 had THR surgery.

CONCLUSION

The study found that the relationships between ethnicity (White/BAME) and gender as well as surgery type (TKR/THR) and gender are statistically important. In all cases with low vitamin D and normal vitamin D levels, White patients had higher overall Oxford hip scores than the BAME patients. To comprehend the differences discovered, further research is needed. To try to eliminate the difference, targeted approaches should be created.

Ethnic Disparities and Incidence of Postoperative Complications in Obese Patients Undergoing Total Knee Arthroplasty: Analysis of the American College of Surgeons National Surgical Quality Improvement Program Data Set

INTRODUCTION

Total knee arthroplasty (TKA) is common but complex operation. A paucity of literature exists on differences between Hispanics and non-Hispanics with TKA. Our study aims to investigate the association between Hispanic ethnicity and complications in obese patients undergoing TKA.

METHODS

This is a retrospective cohort study using the National Surgical Quality Improvement Program database for patients with body mass index ≥30 kg/m2 who underwent TKA. Exposure in this study was ethnicity (Hispanic versus non-Hispanic), and the primary outcome was postoperative complications. Associations between ethnicity and baseline characteristics and between covariates and the outcome were assessed via bivariate analysis. Multiple logistic regression was done to determine associations between Hispanic ethnicity and complications while controlling for confounders.

RESULTS

Thirty five thousand twenty-seven patients were included in our study, of which 6.3% were Hispanic. Among obese adults, Hispanics had a 1.24 (95% CI 1.11 to 1.39) times greater odds of having a postoperative complication after TKA than non-Hispanics. This increased to 1.36 (95% CI 1.20 to 1.54) after adjusting for confounders. Hispanics were notably more likely to receive transfusion (2.62% vs. 1.59%, P < 0.001) and have prolonged length of stay (13.29% vs. 11.12%, P = 0.002) but were less likely to have wound disruption (0.05% vs. 0.27%, P = 0.042).

CONCLUSION

In a national database, Hispanic ethnicity was associated with greater odds of postoperative complication in obese patients undergoing TKA compared with non-Hispanics. Future studies focusing on a wide range metrics of social determinants of health are needed to further investigate barriers and intervention to eliminate racial/ethnic disparities in surgical patients.

Clinical and Radiological Outcomes of Total Knee Arthroplasty Performed with Midvastus and Medial Parapatellar Approaches in Obese Patients

Background

The use of total knee arthroplasty (TKA) for primary osteoarthritis of the knee has remarkably increased recently. We aimed to compare the clinical and radiological outcomes of TKA in obese patients (>30 kg/m²) operated with midvastus (MV) or medial parapatellar (MPP) approaches.

Methods

This retrospective study was performed using data derived from 80 patients (70 women; 10 men) with an average age of 66.17 ± 5.42 (range: 54 to 77). Patients were allocated into 2 groups as for the type of approach conducted during TKA: group I (n = 41) underwent TKA by MV approach, while the MMP technique was used in group II (n = 39).

Results

Demographic, clinical, and radiological parameters included age, side of involvement, sex, BMI, diameters of thigh and calf, length of incision, duration of operation, amount of bleeding and transfusion, duration of hospitalization and follow-up, complications, and range of motion, as well as Knee Society Score (KSS) and Knee Society Function Score (KSFS). Patients with a higher BMI (≥35 kg/m²) experienced more profound bleeding and needed more transfusion of erythrocyte suspension. The range of motion was more favorable in groups with BMI <35 kg/m². The functional outcomes as reflected in KSS and KSFS were much better in patients with BMI <35 kg/m².

Conclusions

Our data indicated that obesity can adversely influence the clinical and radiological outcomes after TKA performed by both MV and MPP approaches. A careful analysis of patient characteristics and selection of appropriate operative procedures is critical. Further randomized, controlled trials on larger series must be designed to elucidate the relationship between obesity and therapeutic outcomes after TKA with different approaches.

Preoperative Nonsurgical Weight Loss Interventions Before Total Hip and Knee Arthroplasty: A Systematic Review

BACKGROUND

An upcoming total joint arthroplasty (TJA) may motivate patients with severe obesity (body mass index [BMI] > 40 kg/m²) to lose weight. Weight loss can optimize outcomes following TJA, and many surgeons use a 40 kg/m² cut-off for undergoing TJA to reduce the risk of complications. However, few patients who are denied TJA for severe obesity successfully lose weight. This is the first systematic review of nonsurgical weight loss interventions before TJA.

METHODS

Five electronic databases were searched for articles on January 11, 2021. Studies that utilized preoperative nonsurgical weight loss interventions for patients with obesity (BMI ≥ 30 kg/m²) scheduled for or awaiting TJA of the hip or knee were included. Two reviewers independently screened articles, assessed methodological quality, and extracted data.

RESULTS

We retrieved 1943 unique records, of which 7 met inclusion criteria including 2 randomized clinical trials and 5 single-arm case series. Overall, weight loss ranged from 5.0 to 32.5 kg. Four interventions reduced BMI by 3 kg/m² at 3-5 months, while 1 reduced BMI by 12.7 kg/m². Other weight outcomes and those related to pain, function, complications, and adverse events were inconsistently reported.

CONCLUSION

Although larger trials are needed, particularly randomized controlled trials that measure preoperative weight loss in a control group, nutritional status, and postoperative complications, the available evidence indicates that short-term, nonsurgical, preoperative weight loss interventions before TJA produce both statistically significant weight loss and reduced BMI before surgery. It remains unknown if the amount of weight loss from these interventions is clinically significant and sufficient to improve outcomes after TJA.

Time Trends in Patient Characteristics and In-Hospital Adverse Events for Primary Total Knee Arthroplasty in the United States: 2010-2017

Background

Perioperative care for total knee arthroplasty (TKA) has improved over time. We present an analysis of inpatient safety after TKA.

Methods

14,057 primary TKAs captured by the Medicare Patient Safety Monitoring System between 2010 and 2017 were retrospectively reviewed. We calculated changes in demographics, comorbidities, and adverse events (AEs) over time. Risk factors for AEs were also assessed.

Results

Between 2010 and 2017, there was an increased prevalence of obesity (35.1% to 57.6%), tobacco smoking (12.5% to 17.8%), and renal disease (5.2% to 8.9%). There were reductions in coronary artery disease (17.3% to 13.4%) and chronic warfarin use (6.7% to 3.1%). Inpatient AEs decreased from 4.9% to 2.5%, (P < .01), primarily driven by reductions in anticoagulant-associated AEs, including major bleeding and hematomas (from 2.8% to 1.0%, P < .001), catheter-associated urinary tract infections (1.1% to 0.2%, P < .001), pressure ulcers (0.8% to 0.2%, P < .001), and venous thromboembolism (0.3% to 0.1%, P = .04). The adjusted annual decline in the risk of developing any in-hospital AE was 14% (95% confidence interval [CI] 10%-17%). Factors associated with developing an AE were advanced age (odds ratio [OR] = 1.01, 95% CI 1.00-1.01), male sex (OR = 1.21, 95% CI 1.02-1.44), coronary artery disease (OR = 1.35, 95% CI 1.07-1.70), heart failure (OR = 1.70, 95% CI 1.20-2.41), and renal disease (OR = 1.71, 95% CI 1.23-2.37).

Conclusions

Despite increasing prevalence of obesity, tobacco smoking, and renal disease, inpatient AEs after primary TKA have decreased over the past several years. This improvement is despite the increasing complexity of the inpatient TKA population over time.

ADSC-Based Cell Therapies for Musculoskeletal Disorders: A Review of Recent Clinical Trials

Recently published clinical trials involving the use of adipose-derived stem cells (ADSCs) indicated that approximately one-third of the studies were conducted on musculoskeletal disorders (MSD). MSD refers to a wide range of degenerative conditions of joints, bones, and muscles, and these conditions are the most common causes of chronic disability worldwide, being a major burden to the society. Conventional treatment modalities for MSD are not sufficient to correct the underlying structural abnormalities. Hence, ADSC-based cell therapies are being tested as a form of alternative, yet more effective, therapies in the management of MSDs. Therefore, in this review, MSDs subjected to the ADSC-based therapy were further categorized as arthritis, craniomaxillofacial defects, tendon/ligament related disorders, and spine disorders, and their brief characterization as well as the corresponding conventional therapeutic approaches with possible mechanisms with which ADSCs produce regenerative effects in disease-specific microenvironments were discussed to provide an overview of under which circumstances and on what bases the ADSC-based cell therapy was implemented. Providing an overview of the current status of ADSC-based cell therapy on MSDs can help to develop better and optimized strategies of ADSC-based therapeutics for MSDs as well as help to find novel clinical applications of ADSCs in the near future.

A Novel, Potentially Universal Machine Learning Algorithm to Predict Complications in Total Knee Arthroplasty

BACKGROUND

There remains a lack of accurate and validated outcome-prediction models in total knee arthroplasty (TKA). While machine learning (ML) is a powerful predictive tool, determining the proper algorithm to apply across diverse data sets is challenging. AutoPrognosis (AP) is a novel method that uses automated ML framework to incorporate the best performing stages of prognostic modeling into a single well-calibrated algorithm. We aimed to compare various ML methods to AP in predictive performance of complications after TKA.

METHODS

Thirty-eight preoperative patient demographics and clinical features from all primary TKAs performed at California-licensed hospitals between 2015 and 2017 were evaluated as predictors of major complications after TKA. Traditional logistic regression (LR), various other ML methods (XGBoost, Gradient Boosting, AdaBoost, and Random Forest), and AP were used for model building to determine discriminative power (area under receiver operating curve), calibration (Brier score), and feature importance.

RESULTS

Between 2015 and 2017, there were a total of 156,750 TKAs with 1109 (0.7%) total major complications. AP had the highest discriminative performance with area under receiver operating curve 0.679 compared with LR, XGBoost, Gradient Boosting, AdaBoost, and Random Forest (0.617, 0.601, 0.662, 0.657, and 0.545, respectively). AP (Brier score 0.007) had similar calibration as the other ML methods (0.006, 0.006, 0.022, 0.007, and 0.008, respectively). The variables that are most important for AP differ from those that are most important for LR.

CONCLUSION

Compared to conventional ML algorithms, AP has superior discriminative ability with similar calibration and suggests nonlinear relationships between variables in outcomes of TKA.

Total Versus Unicondylar Knee Arthroplasty: Does Race Play a Role in the Treatment Selection?

INTRODUCTION

Racial disparities have been well reported in the utilization and outcomes of knee arthroplasty, but it is unclear whether disparities also extend to the choice of surgical treatment. The primary objective of this study is to identify if race plays a role in the selection of unicondylar versus total knee arthroplasty (UKA, TKA) for isolated tibiofemoral osteoarthritis (OA). A secondary objective is to identify the differences in the complication rates for each procedure by racial identity.

METHODS

A retrospective review of the 2006-2018 American College of Surgeons National Surgical Quality Improvement Program was performed. Asian, Black, Hawaiian/Pacific Islander, Hispanic, Native American/Alaskan, and White individuals who underwent primary elective UKA or TKA were compared in terms of UKA vs. TKA utilization rates and outcomes.

RESULTS

A total of 308,715 patients were analyzed. After controlling for all baseline differences, Whites (3.5%), Asians (3.7%), and Hawaiian/Pacific Islanders (3.1%) had around twice the rate of UKA compared to Blacks (1.6%), while Hispanics (2.1%) and Native American/Alaskans (1.7%) were in between (p <0.001). TKA was associated with higher complications compared to UKA in all racial groups (p < 0.001).

CONCLUSION

Minority patients, especially Blacks, were less likely to receive UKA for treatment of isolated knee OA. This is significant because treatment selection in patients who are eligible for UKA can have a significant impact on postoperative recovery and complications rates.

Higher body mass index is associated with larger postoperative improvement in patient-reported outcomes following total knee arthroplasty

BACKGROUND

Total knee arthroplasty is known to successfully alleviate pain and improve function in endstage knee osteoarthritis. However, there is some controversy with regard to the influence of obesity on clinical benefits after TKA. The aim of this study was to investigate the impact of body mass index (BMI) on improvement in pain, function and general health status following total knee arthroplasty (TKA).

METHODS

A single-centre retrospective analysis of primary TKAs performed between 2006 and 2016 was performed. Data were collected preoperatively and 12-month postoperatively using WOMAC score and EQ-5D. Longitudinal score change was compared across the BMI categories identified by the World Health Organization.

RESULTS

Data from 1565 patients [mean age 69.1, 62.2% women] were accessed. Weight distribution was: 21.2% BMI < 25.0 kg/m2, 36.9% BMI 25.0-29.9 kg/m2, 27.0% BMI 30.0-34.9 kg/m2, 10.2% BMI 35.0-39.9 kg/m2, and 4.6% BMI ≥ 40.0 kg/m2. All outcome measures improved between preoperative and 12-month follow-up (p < 0.001). In pairwise comparisons against normal weight patients, patients with class I-II obesity showed larger improvement on the WOMAC function and total score. For WOMAC pain improvements were larger for all three obesity classes.

CONCLUSIONS

Post-operative improvement in joint-specific outcomes was larger in obese patients compared to normal weight patients. These findings suggest that obese patients may have the greatest benefits from TKA with regard to function and pain relief one year post-op. Well balanced treatment decisions should fully account for both: Higher benefits in terms of pain relief and function as well as increased potential risks and complications. Trial registration This trial has been registered with the ethics committee of Eastern Switzerland (EKOS; Project-ID: EKOS 2020-00,879).

The Value of Total Knee Replacement in Patients With Knee Osteoarthritis and a Body Mass Index of 40 kg/m2 or Greater : A Cost-Effectiveness Analysis

BACKGROUND

Total knee replacement (TKR) is an effective and cost-effective strategy for treating end-stage knee osteoarthritis. Greater risk for complications among TKR recipients with a body mass index (BMI) of 40 kg/m2 or greater has raised concerns about the value of TKR in this population.

OBJECTIVE

To assess the value of TKR in recipients with a BMI of 40 kg/m2 or greater using a cost-effectiveness analysis.

DESIGN

Osteoarthritis Policy Model to assess long-term clinical benefits, costs, and cost-effectiveness of TKR in patients with a BMI of 40 kg/m2 or greater.

DATA SOURCES

Total knee replacement parameters from longitudinal studies and published literature, and costs from Medicare Physician Fee Schedules, the Healthcare Cost and Utilization Project, and published data.

TARGET POPULATION

Recipients of TKR with a BMI of 40 kg/m2 or greater in the United States.

TIME HORIZON

Lifetime.

PERSPECTIVE

Health care sector.

INTERVENTION

Total knee replacement.

OUTCOME MEASURES

Cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs), discounted at 3% annually.

RESULTS OF BASE-CASE ANALYSIS

Total knee replacement increased QALYs by 0.71 year and lifetime medical costs by $25 200 among patients aged 50 to 65 years with a BMI of 40 kg/m2 or greater, resulting in an ICER of $35 200. Total knee replacement in patients older than 65 years with a BMI of 40 kg/m2 or greater increased QALYs by 0.39 year and costs by $21 100, resulting in an ICER of $54 100.

RESULTS OF SENSITIVITY ANALYSIS

In TKR recipients with a BMI of 40 kg/m2 or greater and diabetes and cardiovascular disease, ICERs were below $75 000 per QALY. Results were most sensitive to complication rates and preoperative pain levels. In the probabilistic sensitivity analysis, at a $55 000-per-QALY willingness-to-pay threshold, TKR had a 100% and 90% likelihood of being a cost-effective strategy for patients aged 50 to 65 years and patients older than 65 years, respectively.

LIMITATION

Data are derived from several sources.

CONCLUSION

From a cost-effectiveness perspective, TKR offers good value in patients with a BMI of 40 kg/m2 or greater, including those with multiple comorbidities.

PRIMARY FUNDING SOURCE

National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health.

Minority Race and Ethnicity is Associated With Higher Complication Rates After Revision Surgery for Failed Total Hip and Knee Joint Arthroplasty

BACKGROUND

Racial and ethnic disparities in access to hip and knee total joint arthroplasty (TJA) and postoperative outcomes have wide-reaching implications for patients and the health care system. The aim of this study is to evaluate the effect of ethnicity on clinical outcomes and complications following revision hip and knee TJA.

METHODS

A single-institution, retrospective analysis of a consecutive series of 4424 revision hip and knee TJA patients was evaluated. Student's t-test and chi-squared analysis were used to identify significant differences in patient demographics and clinical outcomes between Caucasians and various ethnic minorities, including African Americans, Hispanics, and Asians.

RESULTS

When compared with white patients, African American patients demonstrated a significantly higher BMI (P = .04), ASA score (P = .04), length of hospital stay (P = .06), and postoperative infection rates (P = .04). Hispanics demonstrated a significantly higher BMI (P = .04), when compared with white patients, alongside a significantly higher risk for postoperative infection (P < .01). African American demonstrated a significantly higher ASA score (P = .02; P = .03), when compared with Hispanics and Asians, alongside a significantly increased length of stay (P = .01) and higher risk for postoperative infection (P = .02).

CONCLUSION

The study findings demonstrate an underutilization of revision TJA by ethnic minority groups, suggesting that disparities in access to orthopedic surgery increase from primary to revision surgery despite higher failure rates of minority ethnic groups reported after primary TJA surgery. In addition, inferior postoperative outcomes were associated with African Americans and Hispanics, when compared to white patients, with African Americans demonstrating the highest risk of postoperative complications.

Commercial weight management programmes for patients living with overweight or obesity prior to elective orthopaedic surgery: an evidence review

BACKGROUND

Increased body mass index is associated with increased operative risk during elective joint replacement surgery. Commercial weight management programmes are designed to achieve weight loss. It is not known whether commercial weight management programmes are effective at achieving weight loss in patients awaiting planned hip or knee replacement surgery, or whether achieving significant planned weight loss prior to surgery is associated with changes in surgical outcome.

METHODS

A systematic literature search of seven databases was conducted. Reference lists and grey literature were searched, including commercial weight management programme and medical association websites. Four relevant primary interventional studies were identified.

RESULTS

There is weak, low-quality evidence from four small studies, of which three demonstrated that commercial weight management programmes initiated between 3 and 6 months prior to elective joint replacement surgery are associated with a statistically significant weight loss and body mass index reduction. There is a weak evidence from two studies that peri- and post-operative complications are similar between control and commercial weight management programme groups.

CONCLUSION

There is a paucity of studies investigating commercial weight management programmes aiming to reduce weight in patients living with overweight or obesity awaiting total joint replacement. Further, high-quality research is urgently needed.

Increased Operative Time Impacts Rates of Short-Term Complications After Unicompartmental Knee Arthroplasty

BACKGROUND

Previous evidence has demonstrated an exacerbating effect of increased operative time on short-term complications in total joint arthroplasty. While the same relationship may be expected for unicompartmental knee arthroplasty (UKA), supporting evidence remains sparse. The purpose of this study is to determine the impact of operative time on short-term complication rates after UKA and determine a critical threshold in operative times after which complications may increase.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project was queried from 2007 to 2018 to identify 11,633 UKA procedures that were included in the final analysis. The effect of operative time on complications within 30 days was evaluated using multivariate logistic regression models. Receiver operating characteristics curves and spline regression models were used to identify critical thresholds in operative time that increase the likelihood of short-term complications.

RESULTS

Longer operative times (in minutes) were associated with higher rates of surgical site infection (90.4 ± 26.7 vs 84.8 ± 25.5, P = .003), blood transfusions (94.9 ± 28.6 vs 84.9 ± 25.5, P = .007), as well as reoperation rates (90.8 ± 27.9 vs 84.9 ± 25.5, P = .01), extended hospital length of stay (93.4 ± 29.8 vs 84.5 ± 25.2, P < .001), and mortality (110.4 ± 35.5 vs 84.9 ± 25.5, P = .008). Following multivariate logistic regression, operative time was found to independently predict increased surgical site infection, blood transfusion, myocardial infarction, extended length of stay, and mortality (odds ratio: 1.09 - 1.45, CI: 1.01 - 1.91, all P values <0.02). Receiver operating characteristics curves found an increase in mortality risk during the 30-day postoperative period after 88.5 minutes of operative time, a finding supported by spline regression plots.

CONCLUSION

The present study found a positive correlation between increased operative times and short-term postoperative complication rates after UKA. Despite a statistically significant association with increasing operative time, odds ratios of reported complications are relatively low.