A Prospective, Longitudinal Study of the Influence of Obesity on Total Knee Arthroplasty Revision Rate: Results from the Australian Orthopaedic Association National Joint Replacement Registry

The Estimated Lifetime Risk of Revision After Primary Knee Arthroplasty Is Influenced by Implant Design and Patient Age: Data From the National Joint Registries

BACKGROUND

The aim of this study was to determine the lifetime risk of revision surgery after primary knee arthroplasty (KA) according to implant choice and patient age.

METHODS

The risk of revision according to the implant type (unicondylar, unconstrained, semiconstrained, and fully constrained) was obtained from the National Joint Registry of England and Wales. Mortality risk according to age was estimated from the Scottish Arthroplasty Project (1998 to 2019). The cumulative incidence of revision and death was calculated up to 20 years. The lifetime risk was calculated as a percentage using a multiple decrement life-table methodology.

RESULTS

The lifetime risk of revision varied according to the implant, with unconstrained having the lowest risk and fully constrained and unicondylar having the highest risks, which increased with younger age. For an "average" patient aged between 65 and 69 years, the revision risks for an unconstrained (3.6%, 95% confidence interval [CI] 3.4 to 3.9), semiconstrained (7.2%, 95% CI 3.9 to 13.6), unicondylar (13.7%, 95% CI 12.4 to 15.2), and fully constrained (15.4%, 95% CI 9.2 to 25.7) total KA gradually increased. Relative to an unconstrained KA, the risk of revision for a semiconstrained implant was similar in patients aged < 65 years (relative risk < 2), whereas when this was employed in those ≥ 65 years, the relative risk was more than double (relative risk ≥ 2). Relative to an unconstrained KA, the risk of revision for a fully constrained or a unicondylar KA was more than double in patients aged < 55 years (relative risk > 2) and more than triple (relative risk ≥ 3) in patients ≥ 55 years CONCLUSION: The estimated lifetime risk of revision following KA was dependent on patient age and implant type, with fully constrained and unicondylar KA being associated with a higher lifetime revision risk. There are limitations in the data, and the indication for surgery and the reasons for revision were not assessed.

LEVEL OF EVIDENCE

III.

Bleeding Complications, Transfusion, and Acute Care Costs After Major Arthroplasty in Patients With Hereditary Bleeding Disorders: A National Healthcare Database Analysis

BACKGROUND

Advances in blood conservation have reduced the need for allogeneic transfusions in total knee and hip arthroplasty (TKA/THA). This study aimed to assess whether perioperative bleeding complications, including hemorrhage/hematoma, allogeneic transfusions, and postoperative anemia, occurred at similar rates between patients with hereditary bleeding disorders (BDs) and controls. Using a national health care database, we assessed the use of clotting factor concentrates (CFCs), perioperative outcomes, and resource utilization.

METHODS

A retrospective cohort study was conducted using the Premier Health Database (2017-2021) to analyze differences in outcomes and costs between 1528 patients with hereditary BDs and 20,509 non-BD controls undergoing elective TKA and THA. Summary statistics, bivariate analyses, and odds ratios (ORs) were used to evaluate perioperative outcomes and resource use.

RESULTS

Patients with hereditary BDs were slightly younger, predominantly female, and more often treated at larger, urban hospitals compared to controls. Bleeding complications, including hemorrhage and hematoma, were infrequent but higher in the BD group (1.1% vs 0.2%; P < .0001). Transfusion rates were higher in THA than TKA, with significantly increased odds for patients with hereditary BD: for THA, OR 2.7 (95% confidence interval [CI], 2.0-3.7; P < .0001); and for TKA, OR 2.6 (95% CI, 1.9-3.8; P < .0001). CFC exposures occurred in 16.4% of patients with hereditary BD compared to 0.03% in controls. Of 270 reported CFC exposures, factor VIII (FVIII) and von Willebrand factor (VWF) were most commonly used (49.6% and 23.0%, respectively), followed by FIX concentrate (12.6%) and bypassing agents, including FVIIa (8.5%) and anti-inhibitor coagulant complex (AICC; 3.7%). Antifibrinolytic therapy was administered in most cases. Pharmacy costs for patients with hereditary BD were significantly higher, with a mean of $23,792 (95% CI, $8722-$39,312), being over 30 times the mean cost in controls ($750; 95% CI, $739-$762). Other outcomes were not different, except for a higher incidence of venous thromboembolism in the BD group (OR 3.9, 95% CI, 2.4-6.1; P < .0001).

CONCLUSIONS

THA and TKA in patients with hereditary BDs are relatively safe, with most outcomes comparable to controls. However, higher rates of bleeding, transfusion, and VTE underscore the need for optimizing anemia management and targeted use of CFCs along with antifibrinolytic therapy.

[Influence of obesity on midterm outcome after primary hip and knee arthroplasty in Germany : Analysis from the EPRD]

OBJECTIVES

To determine the influence of obesity on revision rates and mortality after primary elective hip and knee arthroplasty in Germany.

MATERIALS AND METHODS

In the German Arthroplasty Registry (EPRD) there were 403,073 elective total hip arthroplasties (THA), 320,913 bicondylar total knee arthroplasties (TKA) and 48,480 unicondylar knee arthroplasties (UKA) with valid BMI available for analysis. Cumulative revision rates and 1‑year mortality was calculated for BMI groups.

RESULTS

There were increased revision rates with increasing BMI, most distinctive for septic revisions in THA during the first year after surgery (non-obese 0.7%, obesity grade 1 1.3%, grade 2 2.1%, grade 3 4.2%). In TKA and UKA this increase was generally less pronounced. Age- and gender-standardized mortality was lower than expected in most groups, but also increasing with increasing BMI.

CONCLUSION

The risk for revisions in obese patients is more distinctive in hip arthroplasty than in knee arthroplasty and is especially high in morbidly obese patients (BMI ≥ 40 kg/m2). Nonetheless, this risk may be acceptable for affected patients. Therefore, the possible benefits and risks of an arthroplasty should be weighed against each other and individually discussed with the patient.

[Perioperative antibiotic prophylaxis in obesity]

BACKGROUND

In terms of perioperative infections, arthroplasty for obese patients represents a high-risk procedure. Correct antibiotic prophylaxis is a central pillar of infection prophylaxis. Studies showed increased infection rates if an antibiotic other than cefazolin was administered for prophylaxis. In patients with anamnestic penicillin allergy, an existing allergy is extremely rare, and the presence of cross-allergies to cephalosporins is similarly rare. Consequently, every effort should be made to administer a first- or second generation cephalosporin such as cefazolin.

DOSAGE

Whether the dosage of antibiotic prophylaxis should be adjusted to the body weight remains unclear due to the limited data available: case series showed increased infection rates when cefazolin was underdosed and recommended increasing the dose to 3 g if the body weight exceeds 120 kg. However, no studies with a higher level of evidence exist. Published studies on the effective antibiotic levels in the tissue remain contradictory with regard to possible weight-dependent dose adjustments. Similarly, there is insufficient data on whether local intraoperative antibiotic prophylaxis may be useful in obese patients. By contrast, there is no evidence for a positive benefit of double prophylaxis with two different antibiotics or prolonged postoperative antibiotic prophylaxis in obesity.

CONCLUSION

In summary, the data on antibiotic prophylaxis is generally insufficient, especially when focussing on possible dose adjustments in obesity. The well-timed administration of a cephalosporin such as cefazolin represents the golden standard in orthopedics and trauma surgery. A possible dose adjustment to 3 g for a body weight over 120 kg appears reasonable considering the low costs and the broad therapeutic window and is therefore recommended in the current AWMF S3 guideline.

A survey of Scottish Committee for Orthopaedics and Trauma members on lower limb joint replacement practices in morbidly obese patients

Background

Scotland has one of the highest rates of obesity in the developed world which increases risk of lower limb osteoarthritis resulting in total joint arthroplasty (TJA). This paper aimed to investigate (1) current practice of orthopaedic consultants in Scotland in managing end-stage hip and knee osteoarthritis in obese patients, (2) adherence to National guidelines, and (3) understanding of complication risks in lower limb TJA for BMI≥40.

Methods

A 15-question online survey was sent to all active members of Scottish Committee for Orthopaedics and Trauma (SCOT) between February and March 2023 to understand the current practices for managing obese patients with lower limb arthritis requiring joint replacement surgery.

Results

The survey received 62 responses from members of SCOT. The experience ranges from 1 to 44 years (mean 15 years) at consultant level. 61 % of respondents were aware of the SCOT National Guidelines for lower limb TJA in obese patients. 72 % would offer TJA to patients with a BMI>40.35 % would get a second opinion and 22 % discuss these cases in a multidisciplinary team meeting. 71 % were aware of the local weight management guidelines. 77 % quoted risk of deep infection to be between 1 and 30 %, and 40 % quoted risk of amputation between .002 % and 10 % in morbidly obese patients.

Conclusion

Surgical management of obese patients with lower limb osteoarthritis in Scotland is variable. A standardised approach would be beneficial in obtaining informed consent.

[Perioperative management of obese patients undergoing elective hip and knee arthroplasty]

INTRODUCTION

Obesity is a worldwide growing health crisis, affecting younger and younger age groups and posing new challenges for arthroplasty. Due to increased complication rates in this population, many authors are of the opinion that in patients with a body mass index (BMI) of over 40, the problems outweigh the benefits of surgery and that surgery should be postponed until significant weight reduction has been achieved.

MATERIALS AND METHODS

A systematic review of electronic databases (PubMed, Embase, Web of Science and the Cochrane Library) was performed. 49 relevant articles were analyzed. Pre-defined questions were answered based on the literature. The level of evidence for the recommendation was defined in a consensus meeting.

RESULTS

Obese patients with a BMI ≥ 30 have an up to threefold increased perioperative risk, particularly for infections and mechanical complications. In addition, surgery in obese patients is technically demanding, which results in a higher risk of implant malpositioning. Despite these risks, obese patients benefit from surgery in a similar way compared to normal-weight patients, showing comparable improvements in function and quality of life. Preoperative weight loss can reduce the risk but should be long-term to avoid negative metabolic effects. Bariatric surgery and drug therapies can help, but their effects on perioperative risk are unclear. Besides the BMI, careful diagnosis and treatment of comorbidities is crucial.

CONCLUSION

Obese patients benefit from arthroplasty in a similar way to normal-weight patients but have a higher risk of complications, particularly infection. Prior to joint replacement, patients with a BMI of 40 or more should undergo dietary counselling and weight reduction; their metabolic status should be checked, as malnutrition can increase the risk. If weight reduction is not achieved despite these measures, the operation can be performed with increased risks, whereby the patient should be fully informed and involved in the decision-making process.

Antibiotic-loaded bone cement is associated with a reduction of the risk of revision of total knee arthroplasty: Analysis of the Catalan Arthroplasty Register

PURPOSE

The purpose of this study was to analyse the impact on peri-prosthetic joint infection (PJI) rate and prosthetic survival using antibiotic-loaded bone cement (ALBC) versus plain cement during total knee arthroplasty (TKA).

METHODS

A retrospective cohort study was conducted. The main data source was the Catalan Arthroplasty Register (RACat). TKAs with surgery date between 1 January 2011 and 31 December 2020 were analysed and followed up until 31 December 2023. The main variable of interest was the type of cement (ALBC vs. plain cement), and several endpoints (septic revision, aseptic revision, and all-cause revision) were considered. The analysed outcomes were revision rates, survival rates and risk factors' hazard ratios (HR).

RESULTS

A total of 22,781 TKAs were analysed, 13,125 (57.6%) of them with plain cement and 9656 (42.4%) with ALBC. The septic revision rate was lower in the ALBC group after 3 months of follow-up (0.52% vs. 0.78%, p value = 0.04). Prosthetic survival with respect to the aseptic revision endpoint was also higher for the ALBC group during the whole follow-up period (~158 months). Regarding risk factors for infection, ALBC showed a protective effect, HR: 0.53 (0.44, 0.63), while sex (being male) and the analysed comorbidities increased the risk.

CONCLUSIONS

ALBC is associated with a reduction in both the septic revision and the aseptic revision rate after TKA, and thus with higher prosthetic survival.

LEVEL OF EVIDENCE

Level III, Therapeutic, retrospective.

ASA Class Is a Stronger Predictor of Early Revision Risk Following Primary Total Knee Arthroplasty than BMI

Background

Although there is a known correlation between obesity and revision risk following total knee arthroplasty (TKA), there is an ongoing debate regarding the appropriateness of denying TKA solely based on the body mass index (BMI) of a patient. Our aim was to determine whether a patient's American Society of Anesthesiologists (ASA) class predicts their risks of early all-cause revision and revision for periprosthetic joint infection (PJI) following primary TKA, independent of their BMI.

Methods

Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) were obtained regarding all patients who underwent primary TKA for osteoarthritis in Australia from January 1, 2015, to December 31, 2022. Estimated hazard ratios of all-cause revision and revision for PJI, as well as predicted risks of revision within 3 months, 1 year, and 2 years, as a function of patient ASA class and BMI, were calculated with use of multivariable Cox proportional hazards models.

Results

A total of 274,786 primary TKAs (54.5% female; mean age, 68.3 years) were included in the study, of which 5,401 were revised during the study period. Compared with BMI, ASA class was a stronger predictor of the risks of all-cause revision and revision for PJI following primary TKA. Patients with an ASA class of 3 to 4 had higher risks of all-cause revision and revision for PJI at multiple time points after TKA compared with patients with an ASA class of 1 to 2, regardless of BMI.

Conclusions

Although ASA class and BMI are theoretically interrelated variables, we found that a patient's ASA class was more strongly associated with their risks of early all-cause revision and revision for PJI following primary TKA than their BMI. Employing a BMI threshold in isolation when assessing fitness for TKA may be inappropriate, and surgeons should give greater weight to the other medical comorbidities and general perioperative fitness of the patient. Patients with poorly controlled comorbidities should be referred for medical optimization prior to TKA.

Level of Evidence

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

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Chinese Orthopaedic Surgeons

BACKGROUND

Informed by the precedent of an American Association of Hip and Knee Surgeons (AAHKS) survey, where 95% of participants reported instigating modifications to preoperative risk factors, this study appraised the approach of Chinese arthroplasty surgeons toward patients who had modifiable risks.

METHODS

An adaptation of the AAHKS survey tool for a Chinese cohort was undertaken. The survey queried 600 Chinese Society of Hip and Knee Surgeons members on whether the perception of unoptimized medical comorbidities and socioeconomic elements affects the propensity to offer surgical procedures.

RESULTS

Out of the distributed surveys, 150 responses were received, culminating in a response rate of 25%. The data illustrate that 98.7% of Chinese surgeons practice restrictions on arthroplasty access for patients who have modifiable risk factors, with notable frequencies for malnutrition (93.3%), anemia (91.3%), recent hyaluronic acid injections (within one month, 88.7%), and corticosteroid injections (within 3 months, 74.7%). Assessment criteria ahead of surgery included limitations such as a body mass index under 40 (47.3%), requirements for smoking cessation (57.3%), an acceptable hemoglobin A1c level (95.3%), and a dependent fasting blood glucose level (88%). Moreover, 87.3% of respondents endorsed the need for additional interventions for certain socioeconomically disadvantaged patients to achieve successful outcomes. A majority of respondents (94.7%) believed that more equitable access to care, facilitated by better-adjusted payment methodologies, could enhance patient outcomes. Current payment schemes were also perceived by a majority to potentially compromise outcomes for patients who have inadequate social support (80.7%), low socioeconomic status (67.3%), and those lacking insurance (72.7%).

CONCLUSIONS

The consistency of the almost 99% response rate in addressing modifiable risk factors prior to arthroplasty aligns closely with the reported practices in the AAHKS survey. These findings underscore the shared valuation of preoperative risk factor optimization by Chinese and American arthroplasty surgeons, notwithstanding divergent healthcare system structures.

Outcomes of Obese Patients Undergoing Primary Total Knee Arthroplasty: Trends Over 30 Years

BACKGROUND

The rates of obesity among patients undergoing total knee arthroplasty (TKA) have substantially increased. In addition, obesity is a well-established risk factor for complications after TKA. The purpose of this study was to analyze trends in body mass index (BMI) and complication risk among obese patients undergoing primary TKA treated at a single institution over 3 decades.

METHODS

Utilizing an institutional total joint registry, 13,919 primary TKAs performed to treat osteoarthritis between 1990 and 2019 were identified. Patients were stratified by BMI according to the World Health Organization (WHO) classification into 3 groups: non-obese (BMI, <30 kg/m 2 ), WHO Class-I and II obese (BMI, 30 to 39.9 kg/m 2 ), and WHO Class-III obese (BMI, ≥40 kg/m 2 ). Trends in BMI and survivorship free from reoperation, revision, and periprosthetic joint infection (PJI) were analyzed over time while controlling for age, sex, and the Charlson Comorbidity Index.

RESULTS

Over the study period, there was a 90% increase in the prevalence of Class-II obesity (13% to 25%) and a 300% increase in Class-III obesity (3% to 12%). Analysis of the entire cohort demonstrated a decrease in the 2-year risk of any reoperation, any revision, and PJI (p < 0.05 for all) with time. The risk decreased significantly over time for non-obese patients for any reoperation (p = 0.029) and any revision (p = 0.004) and for Class-III obese patients for any reoperation (p = 0.038) and any revision (p = 0.012), but it remained stable for Class-I and II obese patients. The risk of PJI decreased from 1990 to 2019 for non-obese patients (p = 0.005), but there were no significant changes in PJI risk for any obesity group.

CONCLUSIONS

Despite increasing rates of obesity among our patients who underwent TKA, we observed decreasing risks of reoperation, revision, and PJI over time. The risks of reoperation and revision declined among non-obese patients, remained stable for Class-I and II obese patients, and declined for Class-III obese patients. The PJI risk declined for non-obese patients over the study period, but no such decline occurred for any category of obesity. Despite the decreasing risks of reoperation and revision, further work is needed to improve PJI risk in obese patients.

LEVEL OF EVIDENCE

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

Total Joint Arthroplasty Outcomes in Eligible Patients Versus Patients Who Failed to Meet at Least 1 Eligibility Criterion: A Single-Center Retrospective Analysis

BACKGROUND

This study looks to investigate how not meeting eligibility criteria affects postoperative outcomes following total joint arthroplasty surgery.

METHODS

A retrospective review was conducted of total joint arthroplasty patients at a single academic institution. Demographics, laboratory values, and complications were recorded. Continuous and categorical variables were compared using the Student's T-test and the Chi-Square test, respectively. Multivariable analysis was used to control for confounding variables.

RESULTS

Our study included 915 total hip and 1,579 total knee arthroplasty patients. For total hip and total knee arthroplasty, there were no significant differences in complications (P = .11 and .87), readmissions (P = .83 and .2), or revision surgeries (P = .3 and 1) when comparing those who met all criteria to those who did not. Total hip arthroplasty patients who did not meet two criteria had 16.1 higher odds (P = .02) of suffering a complication. There were no differences in complications (P = .34 and .41), readmissions (P = 1 and .55), or revision surgeries (P = 1 and .36) between ineligible patients treated by total joint arthroplasty surgeons and those who were not. Multivariable analysis demonstrated no eligibility factors were associated with outcomes for both total hip and knee arthroplasty.

CONCLUSIONS

There was no significant difference in outcomes between those who met all eligibility criteria and those who did not. Not meeting two criteria conferred significantly higher odds of suffering a complication for total hip arthroplasty patients. Total joint arthroplasty surgeons had similar outcomes to non-total joint surgeons, although their patient population was more complex.

LEVEL OF EVIDENCE

III.

Do patients with osteoarthritis lose weight prior to elective joint replacement?

BACKGROUND

Obesity is a known risk factor for the development of osteoarthritis and the subsequent need for joint replacement. Weight loss has been shown to reduce pain, disability, and the need for joint replacement, particularly in patients with knee osteoarthritis. The aim of this study was to investigate pre-operative weight change in patients with hip, knee, and shoulder osteoarthritis at a regional, public hospital in Australia, to identify opportunities for pre-operative weight-loss intervention.

METHODS

A retrospective review of patients who underwent elective primary total hip (THR), knee (TKR), and shoulder (TSR) replacement for osteoarthritis was conducted between December 2019 and December 2022. BMI data were collected at three time points: (1) general practitioner (GP) referral; (2) orthopaedic clinic review; and (3) pre-admission clinic (PAC) assessment.

RESULTS

A total of 496 patients were included in the study, of which 205 underwent THR, 251 underwent TKR, and 40 underwent TSR. The mean patient age was 67 years, and 46.4% were female. At the time of GP referral, the mean body mass index (BMI) was 31.4 kg/m2. Across the study period, only 2% of patients experienced clinically significant weight loss pre-operatively (≥5% of total body weight).

CONCLUSION

This study has demonstrated that very few patients lose weight prior to undergoing joint replacement in the public sector in Australia. This highlights the need for targeted non-surgical weight loss interventions for patients currently awaiting joint replacement.

Time trends in case-mix and risk of revision following hip and knee arthroplasty in public and private hospitals: a cross-sectional analysis based on 476,312 procedures from the Dutch Arthroplasty Register

BACKGROUND AND PURPOSE

This study aims to assess time trends in case-mix and to evaluate the risk of revision and causes following primary THA, TKA, and UKA in private and public hospitals in the Netherlands.

METHODS

We retrospectively analyzed 476,312 primary arthroplasties (public: n = 413,560 and private n = 62,752) implanted between 2014 and 2023 using Dutch Arthroplasty Register data. We explored patient demographics, procedure details, trends over time, and revisions per hospital type. Adjusted revision risk was calculated for comparable subgroups (ASA I/II, age ≤ 75, BMI ≤ 30, osteoarthritis diagnosis, and moderate-high socioeconomic status (SES).

RESULTS

The volume of THAs and TKAs in private hospitals increased from 4% and 9% in 2014, to 18% and 21% in 2022. Patients in private hospitals were younger, had lower ASA classification, lower BMI, and higher SES compared with public hospital patients. In private hospitals, age and ASA II proportion increased over time. Multivariable Cox regression demonstrated a lower revision risk for primary THA (HR 0.7, CI 0.7-0.8), TKA (HR 0.8, CI 0.7-0.9), and UKA (HR 0.8, CI 0.7-0.9) in private hospitals. After initial arthroplasty in private hospitals, 49% of THA and 37% of TKA revisions were performed in public hospitals.

CONCLUSION

Patients in private hospitals were younger, had lower ASA classification, lower BMI, and higher SES com-pared with public hospital patients. The number of arthroplasties increased in private hospitals, with a lower revision risk compared with public hospitals.

Racial and Ethnic Minority Patients Have Increased Complication Risks When Undergoing Surgery While Not Meeting Clinical Guidelines

BACKGROUND

Clinical guidelines for performing total joint arthroplasty (TJA) have not been uniformly adopted in practice because research has suggested that they may foster inequities in surgical access, potentially disadvantaging minority sociodemographic groups. The aim of this study was to assess whether undergoing TJA without meeting clinical guidelines affects complication risk and leads to disparities in postoperative outcomes.

METHODS

This retrospective cohort study evaluated the records of 11,611 adult patients who underwent primary TJA from January 1, 2010, to December 31, 2020, at an academic hospital network. Based on self-reported race and ethnicity, 89.5% of patients were White, 3.5% were Black, 2.9% were Hispanic, 1.3% were Asian, and 2.8% were classified as other. Patients met institutional guidelines for undergoing TJA if they had a hemoglobin A1c of <8.0% and a body mass index of <40 kg/m 2 and were not currently smoking. A logistic regression model was utilized to identify factors associated with complications, and a mixed-effects model was utilized to identify factors associated with not meeting guidelines for undergoing TJA.

RESULTS

During the study period, 11% (1,274) of the 11,611 adults who underwent primary TJA did not meet clinical guidelines. Compared with the group who met guidelines, the group who did not had higher proportions of Black patients (3.2% versus 6.0%; p < 0.001) and Hispanic patients (2.7% versus 4.6%; p < 0.001). An increased risk of not meeting guidelines at the time of surgery was demonstrated among Black patients (odds ratio [OR], 1.60 [95% confidence interval (CI), 1.22 to 2.10]; p = 0.001) and patients insured by Medicaid (OR, 1.75 [95% CI, 1.26 to 2.44]; p = 0.001) or Medicare (OR, 1.22 [95% CI, 1.06 to 1.41]; p = 0.007). Patients who did not meet guidelines had a higher risk of reoperation than those who met guidelines (7.7% [98] versus 5.9% [615]; p = 0.017), including a higher risk of infection-related reoperation (3.1% [40] versus 1.4% [147]; p < 0.001).

CONCLUSIONS

We found that patients who underwent TJA despite not meeting institutional preoperative criteria had a higher risk of postoperative complications. These patients were more likely to be from racial and ethnic minority groups, to have a lower socioeconomic status, and to have Medicare or Medicaid insurance. These findings underscore the need for surgery-related shared decision-making that is informed by evidence-based guidelines in order to reduce complication burden.

LEVEL OF EVIDENCE

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

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.

Glucagon-Like Peptide Receptor-1 Agonists Used for Medically-Supervised Weight Loss in Patients With Hip and Knee Osteoarthritis: Critical Considerations for the Arthroplasty Surgeon

Patients with morbid obesity and concomitant hip or knee osteoarthritis represent a challenging patient demographic to treat as these patients often present earlier in life, have more severe symptoms, and have worse surgical outcomes following total hip and total knee arthroplasty. Previously, bariatric and metabolic surgeries represented one of the few weight loss interventions that morbidly obese patients could undergo prior to total joint arthroplasty. However, data regarding the reduction in complications with preoperative bariatric surgery remain mixed. Glucagon-like peptide receptor-1 (GLP-1) agonists have emerged as an effective treatment option for obesity in patients with and without diabetes mellitus. Furthermore, recent data suggest these medications may serve as potential anti-inflammatory and disease-modifying agents for numerous chronic conditions, including osteoarthritis. This review will discuss the GLP-1 agonists and GLP-1/glucose-dependent insulinotropic polypeptide dual agonists currently available, along with GLP-1/glucose-dependent insulinotropic polypeptide/glucagon triple agonists presently being developed to address the obesity epidemic. Furthermore, this review will address the potential problem of GLP-1-related delayed gastric emptying and its impact on the timing of elective total joint arthroplasty. The review aims to provide arthroplasty surgeons with a primer for implementing this class of medication in their current and future practice, including perioperative instructions and perioperative safety considerations when treating patients taking these medications.

Frailty Among Revision Total Knee Arthroplasty Recipients: Epidemiology and Propensity Score-weighted Analysis of Effect on In-hospital Postoperative Outcomes

BACKGROUND

Frailty has been shown to correlate with worse outcomes after total knee arthroplasty (TKA), although less is known regarding its effect on revision TKA (rTKA). This study examines the epidemiologic characteristics and inpatient outcomes of patients with frailty undergoing rTKA.

METHODS

Discharge data from National Inpatient Sample registry were used to identify all patients aged 50 years or older who underwent rTKA between 2006 and 2015. Patients were stratified into frail and nonfrail groupings, based on the presence of specific International Classification of Diseases-9 diagnostic coding. An analysis comparing the epidemiology, medical comorbidities, and propensity score-weighted postoperative clinical and economic outcomes of the two groups was done.

RESULTS

From 2006 to the third quarter of 2015, a total of 576,920 patients (17,727 frail) who underwent rTKA were included. The average age in the study's population was 67.2 years, with a female distribution of 57.4%. Frail patients were more likely to exhibit markedly higher rates of almost all modified Elixhauser Comorbities than their nonfrail counterparts. Frail patients were also more likely to undergo different types of revisions, including an increased rate of removal of the prosthesis without replacement. In addition, frail patients displayed increased likelihood of experiencing any postoperative complication, deep vein thrombosis, postoperative anemia, respiratory complications, and wound dehiscence. Frail patients experienced lower rates of discharge home and increased length of stay than the nonfrail cohort.

DISCUSSION

Patients with frailty undergoing rTKA are at markedly higher risk for inpatient postoperative complications and increased length of stay. Understanding the implications of frailty within rTKA is essential for risk assessment and preoperative optimization for this expanding population.

Obesity Severity Predicts Patient Dissatisfaction After Total Knee Arthroplasty

BACKGROUND

Patient dissatisfaction has been reported in 15 to 20% of traditional total knee arthroplasty (TKA) procedures. While contemporary improvements may have positive effects on patient satisfaction, these may be offset by increasing obesity prevalence among patients who have knee osteoarthritis. We performed this study to determine whether obesity severity impacts patient-reported TKA satisfaction.

METHODS

We compared patient demographic characteristics, preoperative expectations, preoperative and minimum 1-year postoperative patient-reported outcome measures as well as postoperative satisfaction level among 229 patients (243 TKAs) who had World Health Organization (WHO) Class II or III obesity (group A), and 287 patients (328 TKAs) who had WHO classifications of normal weight, overweight, or Class I obesity (group B).

RESULTS

Group A patients were younger and had more severe preoperative back and contralateral knee pain, more frequent preoperative opioid medication use, and lower preoperative and postoperative patient-reported outcome measures (P < .01). A similar proportion of patients in both groups expected at least 75% improvement (68.5 versus 73.2%, P = .27). While satisfaction was higher than traditional reporting for both groups (89.4 versus 92.6%, P = .19), group A patients were less likely to be highly satisfied (68.1 versus 78.5%, P = .04) and were more likely to be highly dissatisfied (5.1 versus 0.9%, P < .01).

CONCLUSIONS

Patients who have Class II and III obesity report greater TKA dissatisfaction. Additional studies should help determine whether specific implant designs or surgical techniques may improve patient satisfaction or whether preoperative counseling should incorporate lower satisfaction expectations for patients who have WHO Class II or III obesity.

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.

Go Big or Go Home: Obesity and Total Joint Arthroplasty

Obesity is highly prevalent, and it is expected to grow considerably in the United States. The association between obesity and an increased risk of complications following total joint arthroplasty (TJA) is widely accepted. Many believe that patients with body mass index (BMI) >40 have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following TJA is observational, very heterogeneous, and full of confounding variables. BMI in isolation has several flaws and recent literature suggests shifting from an exclusively BMI <40 cutoff to considering 5 to 10% preoperative weight loss. BMI cutoffs to TJA may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure. When addressing the potential difficulties and by optimizing preoperative assessment and intraoperative management, the surgery can be conducted safely. A multidisciplinary patient-centered approach with patient engagement, shared decision-making, and informed consent is recommended.

The GM-CSF/CCL17 pathway in obesity-associated osteoarthritic pain and disease in mice

OBJECTIVES

We have previously identified a granulocyte macrophage-colony stimulating factor (GM-CSF)/C-C motif ligand 17 (CCL17) pathway in monocytes/macrophages, in which GM-CSF regulates the formation of CCL17, and it is important for an experimental osteoarthritis (OA) model. We explore here additional OA models, including in the presence of obesity, such as a requirement for this pathway.

DESIGN

The roles of GM-CSF, CCL17, CCR4, and CCL22 in various experimental OA models, including those incorporating obesity (eight-week high-fat diet), were investigated using gene-deficient male mice. Pain-like behavior and arthritis were assessed by relative static weight distribution and histology, respectively. Cell populations (flow cytometry) and cytokine messenger RNA (mRNA) expression (qPCR) in knee infrapatellar fat pad were analyzed. Human OA sera were collected for circulating CCL17 levels (ELISA) and OA knee synovial tissue for gene expression (qPCR).

RESULTS

We present evidence that: i) GM-CSF, CCL17, and CCR4, but not CCL22, are required for the development of pain-like behavior and optimal disease in three experimental OA models, as well as for exacerbated OA development due to obesity, ii) obesity alone leads to spontaneous knee joint damage in a GM-CSF- and CCL17-dependent manner, and iii) in knee OA patients, early indications are that BMI correlates with a lower Oxford Knee Score (r = -0.458 and p = 0.0096), with elevated circulating CCL17 levels (r = 0.2108 and p = 0.0153) and with elevated GM-CSF and CCL17 gene expression in OA synovial tissue.

CONCLUSIONS

The above findings indicate that GM-CSF, CCL17, and CCR4 are involved in obesity-associated OA development, broadening their potential as targets for possible treatments for OA.

Hospital variation in revision rates after primary knee arthroplasty was not explained by patient selection: baseline data from 1452 patients in the Danish prospective multicenter cohort study, SPARK

PURPOSE

Revision rates following primary knee arthroplasty vary by country, region and hospital. The SPARK study was initiated to compare primary surgery across three Danish regions with consistently different revision rates. The present study investigated whether the variations were associated with differences in the primary patient selection.

METHODS

A prospective observational cohort study included patients scheduled Sep 2016 Dec 2017 for primary knee arthroplasty (total, medial/lateral unicompartmental or patellofemoral) at three high-volume hospitals, representing regions with 2-year cumulative revision rates of 1, 2 and 5%, respectively. Hospitals were compared with respects to patient demographics, preoperative patient-reported outcome measures, motivations for surgery, implant selection, radiological osteoarthritis and the regional incidence of primary surgery. Statistical tests (parametric and non-parametric) comprised all three hospitals.

RESULTS

Baseline data was provided by 1452 patients (89% of included patients, 56% of available patients). Patients in Copenhagen (Herlev-Gentofte Hospital, high-revision) were older (68.6 ± 9 years) than those in low-revision hospitals (Aarhus 66.6 ± 10 y. and Aalborg (Farsø) 67.3 ± 9 y., p = 0.002). In Aalborg, patients who had higher Body Mass Index (mean 30.2 kg/m² versus 28.2 (Aarhus) and 28.7 kg/m² (Copenhagen), p < 0.001), were more likely to be male (56% versus 45 and 43%, respectively, p = 0.002), and exhibited fewer anxiety and depression symptoms (EQ-5D-5L) (24% versus 34 and 38%, p = 0.01). The preoperative Oxford Knee Score (23.3 ± 7), UCLA Activity Scale (4.7 ± 2), range of motion (Copenhagen Knee ROM Scale) and patient motivations were comparable across hospitals but varied with implant type. Radiological classification ≥ 2 was observed in 94% (Kellgren-Lawrence) and 67% (Ahlbäck) and was more frequent in Aarhus (low-revision) (p ≤ 0.02), where unicompartmental implants were utilized most (49% versus 14 (Aalborg) and 23% (Copenhagen), p < 0.001). In the Capital Region (Copenhagen), the incidence of surgery was 15-28% higher (p < 0.001).

CONCLUSION

Patient-reported outcome measures prior to primary knee arthroplasty were comparable across hospitals with differing revision rates. While radiographic classifications and surgical incidence indicated higher thresholds for primary surgery in one low-revision hospital, most variations in patient and implant selection were contrary to well-known revision risk factors, suggesting that patient selection differences alone were unlikely to be responsible for the observed variation in revision rates across Danish hospitals.

LEVEL OF EVIDENCE

II, Prospective cohort study.

Patients in high- and low-revision hospitals have similar outcomes after primary knee arthroplasty: 1-year postoperative results from the Danish prospective multicenter cohort study, SPARK

PURPOSE

It is well-known that revision rates after primary knee arthroplasty vary widely. However, it is uncertain whether hospital revision rates are reliable indicators of general surgical quality as defined by patients. The SPARK study compared primary knee arthroplasty surgery at three high-volume hospitals whose revision rates differed for unknown reasons.

METHODS

This prospective observational study included primary knee arthroplasty patients (total, medial/lateral unicompartmental and patellofemoral) in two low-revision hospitals (Aarhus University Hospital and Aalborg University Hospital Farsø) and one high-revision hospital (Copenhagen University Hospital Herlev-Gentofte). Patients were followed from preoperatively (2016-17) to 1-year postoperatively with patient-reported outcome measures including Oxford Knee Score (OKS), EQ-5D-5L and Copenhagen Knee ROM (range of motion) Scale. The surgical outcomes were compared across hospitals for patients with comparable grades of radiographic knee osteoarthritis and preoperative OKS. Statistical comparisons (parametric and non-parametric) included all three hospitals.

RESULTS

97% of the 1452 patients who provided baseline data (89% of those included and 56% of those operated) responded postoperatively (90% at 1 year). Hospitals' utilization of unicompartmental knee arthroplasties differed (Aarhus 49%, Aalborg 14%, and Copenhagen 22%, p < 0.001). 28 patients had revision surgery during the first year (hospital independent, p = 0.1) and were subsequently excluded. 1-year OKS (39 ± 7) was independent of hospital (p = 0.1), even when adjusted for age, sex, Body Mass Index, baseline OKS and osteoarthritis grading. 15% of patients improved less than Minimal Important Change (8 OKS) (Aarhus 19%, Aalborg 13% and Copenhagen 14%, p = 0.051 unadjusted). Patients with comparable preoperative OKS or osteoarthritis grading had similar 1-year results across hospitals (OKS and willingness to repeat surgery, p ≥ 0.087) except for the 64 patients with Kellgren-Lawrence grade-4 (Aarhus 4-6 OKS points lower). 86% of patients were satisfied, and 92% were "willing to repeat surgery", independent of hospital (p ≥ 0.1). Hospital revision rates differences diminished during the study period.

CONCLUSIONS

Patients in hospitals with a history of differing revision rates had comparable patient-reported outcomes 1 year after primary knee arthroplasty, supporting that surgical quality should not be evaluated by revision rates alone. Future studies should explore if revision rate variations may depend as much on revision thresholds and indications as on outcomes of primary surgery.

LEVEL OF EVIDENCE

Level II (Prospective cohort study).

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Australian Orthopedic Surgeons

BACKGROUND

There is growing interest in the perioperative management of patients who have indications for hip and knee arthroplasty in the setting of modifiable risk factors such as morbid obesity, poorly controlled diabetes, and smoking. A recent survey of the American Association of Hip and Knee Surgeons (AAHKS) found that 95% of respondents address modifiable risk factors prior to surgery. The aim of this study was to poll Australian arthroplasty surgeons regarding their approach to patients who have modifiable risk factors.

METHODS

The survey tool used in the AAHKS study was adapted for use in the Australian context and distributed to the membership of the Arthroplasty Society of Australia via SurveyMonkey. There were 77 responses received, representing a response rate of 64%.

RESULTS

The majority of respondents were experienced, high volume arthroplasty surgeons. Overall, 91% of respondents restricted access to arthroplasty for patients who have modifiable risk factors. There were 72% restricting access for excessive body mass index, 85% for poor diabetic control, and 46% for smoking. Most respondents made decisions based on personal experience or literature review rather than hospital or departmental pressures. While 49% of surgeons believed that current payment systems did not impair their ability to achieve good outcomes, 58% believed that certain arthroplasty patients would benefit from additional intervention, based on their socioeconomic status.

CONCLUSION

Over 90% of surgeons who responded address modifiable risk factors prior to surgery. This finding aligns with the practice patterns of AAHKS members, despite differences in healthcare systems.

Institutional Adherence to the American Association of Hip and Knee Surgeons Body Mass Index Guidelines Lowers Perioperative Emergency Department Visits in Primary Total Knee Arthroplasty

BACKGROUND

In 2013, the American Association of Hip and Knee Surgeons tasked a workgroup to provide obesity-related recommendations in total joint arthroplasty and determined that patients who had body mass index (BMI) ≥ 40 seeking hip/knee arthroplasty were at increased perioperative risk and recommended preoperative weight reduction. Few studies have shown the actual results of instituting this; therefore, we reported the effect of instituting a BMI < 40 threshold in 2014 on our elective, primary total knee arthroplasties (TKAs).

METHODS

We queried an institutional database to select all TKAs conducted from January 2010 to May 2020. There were 2,514 TKA pre-2014 and 5,545 TKA post-2014 that were identified. The 90-day emergency department (ED) visits, readmissions, and returns-to-operating room (OR) outcomes were identified. Patients were propensity score weight-matched as per comorbidities, age, initial surgical consultation (consult) BMI, and sex. We conducted 3 outcome comparisons: (1) pre-2014 patients who had a consult and surgical BMI ≥ 40 against post-2014 patients who had a consult BMI ≥ 40 and surgical BMI < 40; (2) pre-2014 patients against post-2014 patients who had a consult and surgical BMI < 40; (3) post-2014 patients who had a consult BMI ≥ 40 and surgical BMI < 40 against post-2014 patients who had a consult BMI ≥ 40 and surgical BMI ≥ 40.

RESULTS

Pre-2014 patients who had a consult and surgical BMI ≥ 40 had more ED visits (12.5% versus 6%, P = .002) but similar readmissions and returns-to-OR than post-2014 patients who had a consult BMI ≥ 40 and surgical BMI < 40. Pre-2014 patients who had a consult and surgical BMI < 40 had more readmissions (8.8% versus 6%, P < .0001) but similar ED visits and returns-to-OR when compared to their post-2014 counterparts. Post-2014 patients who had a consult BMI ≥ 40 and surgical BMI < 40 had fewer ED visits (5.8% versus 10.6%) but similar readmissions and returns-to-OR than patients who had a consult BMI ≥ 40 and surgical BMI ≥ 40.

DISCUSSION

Patient optimization prior to total joint arthroplasty is essential. Enacting BMI reduction pathways prior to total knee arthroplasty seems to afford morbidly obese patients major risk mitigation. We must continue to ethically balance the pathology, expected improvement after surgery, and the overall risks of complications for each patient.

LEVEL OF EVIDENCE

III.