Finding the Optimal Screening Test for Periprosthetic Joint Infection: A Prospective Study

BACKGROUND

No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Serological markers are often used as screening tools to avoid unnecessary joint aspiration in cases with a low probability of infection. This study aimed to determine the utility of standard-of-care serological tests as a screening tool for PJI in patients undergoing revision arthroplasty.

METHODS

This prospective study enrolled 502 patients undergoing revision hip or knee arthroplasty between May 2017 and August 2021. A PJI was defined using a modified definition of the 2018 International Consensus Meeting criteria. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. There were 82 patients undergoing reimplantation who were excluded. Additionally, 8 patients who had an inconclusive International Consensus Meeting score were also excluded. Of the 412 included patients, 317 (76.9%) underwent revision for aseptic failure, and 95 (23.1%) had PJI. Receiver operating characteristic curves were used to assess the diagnostic utility of each serological test. A pairwise comparison with Bonferroni correction was performed to determine whether the differences in areas under the curve (AUCs) between the tests were significant. Additional analyses were performed to find the threshold for each test that offered 100% sensitivity, allowing it to be the optimal screening test.

RESULTS

All 4 serological markers, D-dimer (AUC 0.860, sensitivity 81.3%, specificity 81.7%), CRP (AUC 0.862, sensitivity 90.4%, specificity 70.0%), ESR (AUC 0.833, sensitivity 73.9%, specificity 85.2%), and fibrinogen (AUC 0.798, sensitivity 74.7%, specificity 75.4%), demonstrated comparable accuracy for the diagnosis of PJI (all P > .05). When maximizing sensitivity to 100%, D-dimer demonstrated the highest specificity (AUC 0.860, specificity 40.2%), outperforming ESR (AUC 0.833, specificity 3.3%), fibrinogen (AUC 0.798, specificity 2.3%), and CRP (AUC 0.862, specificity 0%). A plasma D-dimer level of ≥ 244 ng/mL was identified as the optimal cutoff for use as a screening test.

CONCLUSIONS

Although plasma D-dimer demonstrated similar diagnostic accuracy as CRP, ESR, and fibrinogen, it outperformed all 3 aforementioned serological markers when used as a screening test for PJI.

LEVEL OF EVIDENCE

Level II.

Unplanned Emergency Department Visits Following Revision Total Joint Arthroplasty: Incidences, Risk Factors, and Mortalities

BACKGROUND

The incidence of unplanned emergency department (ED) visits following revision total joint arthroplasty is an indicator of the quality of postoperative care. The aim of this study was to investigate the incidences, timings, and characteristics of ED visits within 90 days after revision total joint arthroplasty.

METHODS

A retrospective review of 457 consecutive cases, including 254 revision total hip arthroplasty (rTHA) and 203 revision total knee arthroplasty (rTKA) cases, was conducted. Data regarding patient demographics, timings of the ED encounter, chief complaints, readmissions, and diagnoses indicating reoperation were analyzed.

RESULTS

The results showed that 41 patients who had rTHA (16.1%) and 14 patients who had rTKA (6.9%) returned to the ED within 90 days postoperatively. The incidence of ED visits was significantly higher in the rTHA group than in the rTKA group (P = .003). The most common surgery-related complications were dislocation among rTHA patients and wound conditions among rTKA patients. Apart from elevated calculated comorbidity scores, peptic ulcer in rTHA patients and cerebral vascular events and chronic obstructive pulmonary disease in rTKA patients might increase chances of unplanned ED visits. Patients who had ED visits showed significantly higher mortality rates than the others in both rTHA and rTKA cohorts (P = .050 and P = .008, respectively).

CONCLUSIONS

The ED visits within 90 days are more common after rTHA than after rTKA. Patients in both ED visit groups after rTHA and rTKA demonstrated worse survival. Efforts should be made to improve quality of care to prevent ED visits.

Medicaid Patients Travel Disproportionately Farther for Revision Total Joint Arthroplasty

BACKGROUND

Access to high-quality care for revision total joint arthroplasty (rTJA) is poorly understood but may vary based on insurance type. This study investigated distance traveled for hip and knee rTJA based on insurance type.

METHODS

A total of 317 revision hips and 431 revision knees performed between 2010 and 2020 were retrospectively reviewed. Cluster sampling was used to select primary hips and knees for comparison. Median driving distance was compared based upon procedure and insurance type.

RESULTS

Revision hip and knee patients traveled 18.2 and 11.0 miles farther for surgery compared to primary hip and knee patients (P ≤ .001). For hip rTJA, Medicaid patients traveled farther than Medicare patients followed by commercially insured patients with median distances traveled of 98.4, 67.2, and 35.6 miles, respectively (P = .016). Primary hip patients traveled the same distance regardless of insurance type (P = .397). For knee rTJA, Medicaid patients traveled twice as far as Medicare and commercially insured patients (medians of 85.0, 43.5, and 42.2 miles respectively, P ≤ .046). Primary knee patients showed a similar pattern (P = .264). Age and ASA-PS classification did not indicate greater comorbidity in Medicaid patients.

CONCLUSION

Insurance type may influence rTJA referrals, with disproportionate referral of Medicaid and Medicare patients to nonlocal care centers. In addition to patient burden, these patterns potentially present a financial burden to facilities accepting referrals. Strategies to improve equitable access to rTJA, while maintaining the highest and most economical standards of care for patients, providers, and hospitals, are encouraged.

Extended Oral Antibiotics Increase Bacterial Resistance in Patients Who Fail 2-Stage Exchange for Periprosthetic Joint Infection

BACKGROUND

Although studies have demonstrated reductions in recurrent periprosthetic joint infection (PJI) with the administration of prolonged oral antibiotics at second-stage reimplantation, the potential for increasing bacterial resistance has not been studied. The purpose of this study was to determine if oral antibiotics at second-stage reimplantation increased the rate of antibiotic resistance in subsequent infections.

METHODS

We retrospectively reviewed patients who underwent 2-stage exchange for chronic PJI from 2014 to 2019. We compared those who had received prolonged oral antibiotics at the time of stage 2 reimplantation with those who did not. The primary outcome was the presence of resistant organisms in any subsequent infection. The secondary outcome was the overall rate of recurrent PJI in the 2 groups. Multivariable analyses controlling for demographics and comorbid conditions were used.

RESULTS

Of the 211 patients who underwent 2-stage exchange for PJI, 158 patients received prolonged oral antibiotics. The mean follow-up was 2.2 years. Recurrent PJI was diagnosed in 24 of 158 (15%) patients who received oral antibiotics compared with 11 of 53 (21%) patients who did not receive antibiotics (P = .35). PJI with resistant organisms was identified in 16 of 24 (67%) patients who received antibiotics compared with 0 of 11 (0%) patients who did not receive antibiotics (P = .0001).

CONCLUSIONS

Prolonged oral antibiotics following 2-stage exchange increase drug resistance to that antibiotic in subsequent PJI. We recommend further research in the area to refine antimicrobial protocols as we consider the risks and benefits of prolonged antibiotic treatment.

The Cost of Hip and Knee Revision Arthroplasty by Diagnosis-Related Groups: Comparing Time-Driven Activity-Based Costing and Traditional Accounting

BACKGROUND

Traditional hospital cost accounting (TA) has innate disadvantages that limit the ability to meaningfully measure care pathways and quality improvement. Time-driven activity-based costing (TDABC) allows a meticulous account of costs in primary total joint arthroplasty (TJA). However, differences between TA and TDABC have not been examined in revision hip and knee TJA (rTJA). We aimed to compare total costs of rTJA by the diagnosis-related group (DRG), measured by TDABC vs TA.

METHODS

Overall costs were calculated for rTJA care cycles by DRG for 2 years of financial data (2018-2019) at our single-specialty orthopedic institution using TA and TDABC. Costs derived from TDABC, based on time and resources used, were compared with costs derived from TA based on historical costs. Proportions of implant and nonimplant costs were measured to total TA costs.

RESULTS

Seven hundred ninety-three rTJAs were included in this study, with TA methodology resulting in higher cost estimates. The total cost per DRG 468, rTJA with no comorbidities or complications (CC), DRG 467, rTJA with CC, and DRG 466, rTJA with major CC, estimated by TDABC was 69%, 67%, and 49% of the estimation by TA, respectively. Implant and nonimplant costs represented different proportions between methodologies.

CONCLUSION

Considerable differences exist, as TA estimations were 31%-51% higher than TDABC. The true cost is likely a value between the estimations, but TDABC presents granular and patient-specific cost data. TDABC for rTJA provides valuable bottom-up information on cost centers in the care pathway and, with targeted interventions, may lead to a more optimal delivery of value-based health care.

Financial Burden of Revision Hip and Knee Arthroplasty at an Orthopedic Specialty Hospital: Higher Costs and Unequal Reimbursements

BACKGROUND

As demand for primary total joint arthroplasty (TJA) continues to grow, a proportionate increase in revision TJA (rTJA) is expected. It is essential to understand costs and reimbursement of rTJA as our country moves to bundled payment models. We aimed (1) to characterize implant and total hospital costs, (2) assess reimbursement, and (3) determine revenue for rTJA in comparison with primary TJA.

METHODS

The average implant and total hospital cost of all primary and rTJA procedures by diagnosis-related group (DRG) was calculated using time-driven activity-based costing at an orthopedic hospital from 2018 to 2020. Average reimbursement and payer type were assessed by DRG. Revenue was calculated by deducting average time-driven activity-based costing total costs from reimbursement.

RESULTS

13,946 arthroplasties were included in the study. Implant cost comprised 55.8% of total hospital costs for rTJA DRG 468, compared with 43.6% of total hospital costs for primary TJA DRG 470. Total hospital costs for DRG 468 were 61.1% more than DRG 470. Reimbursement for rTJA was 1.23x more than primary TJA. Private payers paid 23.2% more than Medicare for rTJA. Margin for DRG 468 was 1.5% less than primary DRG 470.

CONCLUSION

rTJA requires more hospital resources and costs than primaries, yet hospital reimbursement may be inadequate with the additional expenditures necessary to provide optimal care. If hospitals cannot perform revision services under the current reimbursement model, patient access may be limited. Implant costs are a major contributor to overall rTJA cost. Strategies are needed to reduce revision implant costs to improve value of care.

LEVEL OF EVIDENCE

Level III, economic and decision analysis.

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.

How to Develop a Fair Revision Arthroplasty Bundle? Using Perioperative Complications and Readmissions to Investigate

BACKGROUND

The next frontier for value-based health care in total joint arthroplasty is revision surgery. Although the disparity in health care utilization between revision procedures compared with primary total hip and total knee arthroplasty (THA/TKA) procedures is recognized, no agreement regarding the risk adjustment necessary to make revision bundles fair to both payors and providers exists. The purpose of this study is to use the risk of perioperative complications and readmissions of patients undergoing revision THA/TKA to establish the foundations of a fair revision arthroplasty bundle.

METHODS

We retrospectively evaluated a consecutive series of 484 aseptic THA/TKA revisions performed at our institution over a 12-month period and compared complications, length of stay, reoperations, and 90-day readmissions to a group of 802 consecutive patients undergoing primary THA/TKA.

RESULTS

169 (34.9%) patients experienced major complications after revision THA/TKA compared with 176 (21.9%) patients undergoing primary THA/TKA (P < .001), (OR 1.91 CI 1.49-2.45, P < .001). Patients undergoing revision TKA were 3.64 times more likely to require hospitalization greater than 3 days (OR 2.59-5.12, CI 95%, P < .001), whereas patients undergoing revision THA were 4.46 times more likely to require hospitalization greater than 3 days (OR 2.89-6.87, CI 95%, P < .001). Revision patients were 3X more likely to have a 90-day readmission and 4X more likely to have a reoperation.

CONCLUSION

For a revision bundle to be fair and widely adopted, either significant financial incentive must be instituted or the latitude given to exclude outliers from the final reconciliation. This must be adjusted to not disincentivize institutions from providing care for failed hip and knee arthroplasties.

Revision Versus Primary Hospital Consumer Assessment of Healthcare Providers and Systems Scores in Total Joint Arthroplasty

BACKGROUND

The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) score is a nationally standardized measure of a patient's inpatient experience. This study aims to assess whether HCAHPS scores differ between patients undergoing primary total joint arthroplasty (TJA) and patients undergoing revision TJA.

METHODS

Patients who underwent primary or revision total hip or total knee arthroplasty (THA or TKA) and returned a completed HCAHPS survey were included in this study. HCAHPS scores were collected from our institution's Center for Quality and Patient Safety department, which was cross-referenced with our hospital's electronic data warehouse. Patient demographics, surgical factors, and quality outcomes were queried. Appropriate statistical analyses were performed using MatLab 2017a and P-values less than .05 were deemed significant.

RESULTS

In total, 523 primary and 59 revision THA recipients completed HCAHPS surveys at our institution between October 2011 and November 2016. During this same period, 507 primary TKA recipients and 40 revision TKA recipients completed HCAHPS surveys. Compared to revision THA, primary THA patients had a significantly higher top box for overall hospital ratings (58.46% vs 41.38%), felt that nurses listened to them carefully (84.3% vs 72.88%), and felt that they clearly understood the role of each medication (69.48% vs 56.90%). Moreover, 18 of 20 HCAHPS question responses favored primary THA despite not reaching significance for the majority of HCAHPS questions. Patients with revision TKA demonstrated a significantly higher incidence of "top box" choices for quieter rooms and a trend favoring better HCAHPS scores in revision TKA in a further 12 of 20 HCAHPS responses.

CONCLUSION

Patients undergoing primary THA report higher HCAHPS scores than those undergoing revision THA, while revision TKA demonstrated a general trend toward higher scores when compared to primary TKA patients. This publicly reported quality measurement metric which factors into physician reimbursement may be biased by the patient's health status, the complexity of the surgical procedure, and length of stay in hospital rather than a true reflection of the quality of their hospital experience.

Bundled Payment "Creep": Institutional Redesign for Primary Arthroplasty Positively Affects Revision Arthroplasty

BACKGROUND

Revision total joint arthroplasty (TJA) is associated with increased readmissions, complications, and expense compared to primary TJA. Bundled payment methods have been used to improve value of care in primary TJA, but little is known of their impact in revision TJA patients. The purpose of this study is to evaluate the impact of a care redesign for a bundled payment model for primary TJA on quality metrics for revision patients, despite absence of a targeted intervention for revisions.

METHODS

We compared quality metrics for all revision TJA patients including readmission rate, use of post-acute care facility after discharge, length of stay, and cost, between the year leading up to the redesign and the 2 years following its implementation. Changes in the primary TJA group over the same time period were also assessed for comparison.

RESULTS

Despite a volume increase of 37% over the study period, readmissions declined from 8.9% to 5.8%. Use of post-acute care facilities decreased from 42% to 24%. Length of stay went from 4.84 to 3.92 days. Cost of the hospital episode declined by 5%.

CONCLUSION

Our health system experienced a halo effect from our bundled payment-influenced care redesign, with revision TJA patients experiencing notable improvements in several quality metrics, though not as pronounced as in the primary TJA population. These changes benefitted the patients, the health system, and the payers. We attribute these positive changes to an altered institutional mindset, resulting from an invested and aligned care team, with active physician oversight over the care episode.