The Impact of Frailty Is Age Dependent in Patients Undergoing Primary Total Knee Arthroplasty: The Age-Adjusted Modified Frailty Index

Frailty and the incidence of surgical site infection after total hip or knee arthroplasty: A meta-analysis

BACKGROUND

Surgical site infection (SSI) remains a critical postoperative complication after total hip and knee arthroplasty (THA and TKA). Frailty, a condition characterized by decreased physiological reserve and increased vulnerability to stressors, may influence the risk of SSI in these patients. This meta-analysis aims to evaluate the association between frailty and the incidence of SSI following THA or TKA.

METHODS

A systematic search of databases including PubMed, EMBASE, Web of Science, Wanfang, and CNKI was conducted to identify relevant studies. Data were extracted and pooled using a random-effects model to calculate the overall risk ratio (RR) and 95 % confidence intervals (CIs).

RESULTS

A total of ten studies comprising 1,036,787 patients met the inclusion criteria. The meta-analysis revealed that frail patients undergoing THA or TKA had a significantly higher risk of developing SSI compared to non-frail patients (RR = 1.64, 95 % CI: 1.39-1.93, p < 0.001, I2 = 66 %). Subgroup analyses indicated that the type of arthroplasty (hip vs. knee) and the method of frailty assessment did not significantly alter the association. Further subgroup analysis suggested that frailty was significantly associated with a higher incidence of deep SSI including joint infection (RR = 1.77, 95 % CI: 1.27-1.48, p < 0.001), but not the incidence of superficial SSI (RR = 1.57, 95 % CI: 0.45-5.42, p = 0.48). The association between frailty and SSI remains in subgroup of multivariate studies only (RR = 1.56, 95 % CI: 1.34 to 1.80, p < 0.001).

CONCLUSIONS

Frailty is a potential predictor of SSI following TKA/THA.

Should Chronological Age be a Consideration in Patients Undergoing Elective Primary Total Knee Arthroplasty?

BACKGROUND

The optimal time for total knee arthroplasty (TKA) requires a balance between patient disability and health state to minimize complications. While chronological age has not been shown to be predictive of complications in elective surgical patients, there is a point beyond which even optimized elderly patients would be at increased risk for complications. The purpose of this study was to examine the impact of chronological age on complications following primary TKA.

METHODS

Using an administrative database, the records of 2,129,191 patients undergoing elective unilateral TKA between 2006 and 2021 were reviewed. The primary outcomes of interest were cardiac and pulmonary complications, and their relationship to the Charlson-Deyo Comorbidity Index (CDI) and chronological age. Secondary outcomes included risk of renal, neurologic, infection, and intensive care utilization postoperatively. The results were analyzed using a graphical method. The impact of chronological age as a modifier of overall risk for complications was modeled as a continuous variable. An age cutoff threshold of 80 years was also assigned for clinical convenience.

RESULTS

The risk of complications correlated more closely to the CDI (odds ratio (OR) 1.37 to 2.1) than chronological age (OR 1.0 to 1.1) across the various complications [Table 1. However, beyond age 80 years, the risks of cardiac, pulmonary, renal, and cerebrovascular complications were significantly increased for all CDI categories (OR 1.73 to 3.40) compared to patients below age 80 years [Table 2] [Figures 1A and 1B].

CONCLUSIONS

Chronologic age can impact the risk of complications even in well-optimized elderly patients undergoing primary TKA. As arthroplasty continues to transition to outpatient settings and inpatient denials increase, these results can help patients, physicians, and payors mitigate risk while optimizing the allocation of resources.

Demographic and Socioeconomic Trends of Patients Undergoing Total Knee Arthroplasty From 2013 to 2022-An Analysis From an Urban Orthopaedic Hospital

BACKGROUND

As worldwide utilization of total knee arthroplasty (TKA) broadens, demographic trends can help make projections to inform access to care. This study aimed to assess the temporal trends in the socioeconomic and medical demographics of patients undergoing TKA.

METHODS

A retrospective review of 15,848 patients who underwent primary, elective TKA at an urban, New York City-based academic medical center between January 2013 and September 2022 was performed. Trends in patients' age, body mass index (BMI), socioeconomic status (SES) (based on median income by patients' ZIP code), race, and Charlson comorbidity index were evaluated using the Mann-Kendall test.

RESULTS

In the last decade, mean patient age (65 to 68 years, P < .001) and Charlson comorbidity index (1.4 to 2.3, P < .001) increased significantly. The proportion of patients who had a BMI ≥ 30 and < 40 increased (43.8 to 51.2%, P = .002), while the proportion of patients who had a BMI ≥ 40 (13.7 to 12.1%, P = .015) and BMI < 30 (42.5 to 36.8%, P = .020) decreased. The distribution of patients' race and SES did not change from 2013 to 2022; Black (18.1 to 16.8%, P = .211) and low SES (12.9 to 11.3%, P = .283) patients consistently represented a minority of TKA patients.

CONCLUSIONS

Over the last decade, the average age and comorbidity burden of TKA patients at our institution have increased. This portends the need for higher levels of preoperative optimization and postoperative management for TKA patients. A decreased prevalence of BMI ≥40 could reflect optimization efforts. However, the consistently low prevalence of Black and low-SES patients suggests that recent payment models did not improve access to care for these populations.

LEVEL OF EVIDENCE

IV.

Trends in the Adoption of Outpatient Joint Arthroplasties and Patient Risk: A Retrospective Analysis of 2019 to 2021 Medicare Claims Data

INTRODUCTION

Total joint arthroplasties (TJAs) have recently been shifting toward outpatient arthroplasty. This study aims to explore recent trends in outpatient total joint arthroplasty (TJA) procedures and examine whether patients with a higher comorbidity burden are undergoing outpatient arthroplasty.

METHODS

Medicare fee-for-service claims were screened for patients who underwent total hip, knee, or shoulder arthroplasty procedures between January 2019 and December 2022. The procedure was considered to be outpatient if the patient was discharged on the same date of the procedure. The Hierarchical Condition Category Score (HCC) and the Charlson Comorbidity Index (CCI) scores were used to assess patient comorbidity burden. Patient adverse outcomes included all-cause hospital readmission, mortality, and postoperative complications. Logistic regression analyses were used to evaluate if higher HCC/CCI scores were associated with adverse patient outcomes.

RESULTS

A total of 69,520, 116,411, and 41,922 respective total knee, hip, and shoulder arthroplasties were identified, respectively. Despite earlier removal from the inpatient-only list, outpatient knee and hip surgical volume did not markedly increase until the pandemic started. By 2022Q4, 16%, 23%, and 36% of hip, knee, and shoulder arthroplasties were discharged on the same day of surgery, respectively. Both HCC and CCI risk scores in outpatients increased over time ( P < 0.001).

DISCUSSION

TJA procedures are shifting toward outpatient surgery over time, largely driven by the COVID-19 pandemic. TJA outpatients' HCC and CCI risk scores increased over this same period, and additional research to determine the effects of this should be pursued.

LEVEL OF EVIDENCE

Level III, therapeutic retrospective cohort study.

Age-adjusted 5-factor modified frailty index as a valuable tool for patient selection in bilateral simultaneous total knee arthroplasty

Although bilateral simultaneous total knee arthroplasty (BSTKA) is an effective treatment for bilateral knee osteoarthritis, safety concerns and lack of precise patient selection criteria persist. The purpose of this retrospective study was to determine the complication rate and the role of frailty in patient selection for BSTKA. We analyzed data from 434 patients who underwent BSTKA between February 2012 and January 2021, examining demographic factors and preoperative blood test results. Complications occurred in 77 patients (18%), with anemia requiring transfusion being the most common (26 patients, 5.9%). In the univariate analysis, age ≥ 75 years, age-adjusted Charlson Comorbidity Index ≥ 5, age-adjusted 5-factor modified Frailty Index (aamFI-5) ≥ 3, hemoglobin ≤ 11.0 g/dL, albumin ≤ 3.5 g/dL, estimated glomerular filtration rate < 45 ml/dl/1.73 m2, and D-dimer ≥ 2.0 μg/mL contributed to postoperative complications (p < 0.05). Multivariate analysis identified aamFI-5 ≥ 3 as an independent risk factor (p = 0.002). Our findings underscore the practical utility of aamFI-5 in predicting complications after BSTKA, providing valuable guidance to surgeons in the selection of BSTKA candidates and ultimately improving clinical outcomes.

Age-Adjusted Modified Frailty Index: Association With Hip Fracture Discharge Functional Dependence

INTRODUCTION

Hip fractures are a common traumatic injury that carry significant morbidity and mortality, and prognostication of functional outcome is becoming increasingly salient. Across multiple surgical specialties, the five-item and 11-item Modified Frailty Index (mFI-5 and mFI-11) have been found to be convenient, quick, and sensitive tools for identifying patients at risk for perioperative complications. A prior study described the superiority of an Age-Adjusted Modified Frailty Index (aamFI) for predicting perioperative complications compared to the mFI-5 in an elective hip surgery. We sought to externally validate the aamFI in a multicenter hip fracture cohort and hypothesize that these risk scores would not only predict functional dependence (FD) at discharge, but that the aamFI would outperform the mFI-5 and mFI-11.

METHODS

The Pennsylvania Trauma Systems Foundation registry was queried from 2010 to 2020 for CPT codes, ICD-9 and ICD-10 codes pertaining to hip fracture patients. Patients with missing locomotion and transfer mobility data were excluded. FD status was determined by discharge locomotion and transfer mobility scores per existing methodology. Univariable and Multivariable analysis as well as receiver operator characteristic curves were used to evaluate and compare the three indices for prediction of functional status at discharge. P value < 0.05 was considered significant.

RESULTS

Twelve thousand seven hundred and forty patients met inclusion criteria (FD: 8183; functional independent 4557). On univariable logistic regression analysis, the mFI-11 (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.47-1.58, P < 0.05), mFI-5 (OR 1.57, 95% CI 1.51-1.63), and aamFI (OR 1.57, 95% CI 1.52-1.62, P < 0.05) were associated with FD. On multivariable logistic regression analysis for predictors of FD, when controlling for age (for the mFI-11 and mFI-5), sex, injury severity score, and admission vitals (systolic blood pressure and respiratory rate), higher mFI-11 and mFI-5 scores independently predicted FD at discharge (OR 1.23, 95% CI 1.18-1.28, P < 0.05 and OR 1.23, 95% CI 1.18-1.29P < 0.05 respectively). Higher aaMFI scores had superior association with functional dependence (OR 1.59, 95% CI 1.54-1.64, P < 0.05). Receiver operator characteristic curves for the mFI-11, mFI-5, and aaMFI showed comparable diagnostic strength (area under curve [AUC] = 0.63 95% CI 0.62-0.64, P < 0.05; AUC = 0.63 95% CI 0.62-0.64, P < 0.05; and AUC = 0.67 95% CI 0.65-0.67, P < 0.05 respectively).

CONCLUSIONS

The mFI-11, mFI-5, and aamFI are predictive of functional outcome following hip fracture. By including age, the aamFI retains the ease of use of the mFI-5 while improving its prognostic utility for functional outcome.

Age-Adjusted Modified Frailty Index Predicts 30-Day Complications and Mortality in Aseptic Revision Total Hip and Knee Arthroplasty

BACKGROUND

The age-adjusted modified frailty index (aamFI) has been demonstrated to effectively predict postoperative complications and healthcare resource utilization in patients undergoing primary total joint arthroplasty. The purpose of this study was to evaluate the applicability of aamFI in patients undergoing aseptic revision total hip (rTHA) and knee arthroplasty (rTKA).

METHODS

A national database was queried for patients undergoing aseptic rTHA and rTKA from 2015 to 2020. A total of 13,307 rTHA and 18,762 rTKA cases were identified. The aamFI was calculated by adding 1 additional point for age ≥73 years to the previously described 5-item modified frailty index (mFI-5). The area under the curve was calculated and compared to compare predictive accuracy between mFI-5 and aamFI. Logistic regression was used to investigate the relationship between aamFI and 30-day complications.

RESULTS

The incidence of incurring any (≥1) complication increased from 15% for aamFI 0 to 45% for aamFI ≥5 after rTHA and from 5 to 55% after rTKA. Patients who had an aamFI ≥3 (reference aamFI = 0) had increased odds (rTHA: odds ratio (OR) 3.5, 95% confidence interval (CI) 2.9 to 4.1, P < .001; rTKA: OR 4.2, 95% CI 4.4 to 5.1, P < .001) of incurring at least 1 complication. The aamFI, compared to mFI-5, was a more accurate predictor of any complication (rTHA P < .001; rTKA P < .001) and 30-day mortality (rTHA P < .001; rTKA P < .003).

CONCLUSION

The aamFI is an excellent predictor of complications in patients undergoing rTHA and rTKA. The addition of chronological age to the previously described mFI-5 improves the predictive value of this simple metric.