Referral Bias in Primary Total Knee Arthroplasty: Retrospective Analysis of 22,614 Surgeries in a Tertiary Referral Center

Early Clinical Outcomes of "Lemon-Dropped" Complex Primary Total Joint Arthroplasty Patients to a Tertiary Care Center

BACKGROUND

In the era of value-based care, pressures lead to cherry-picking healthier patients and lemon-dropping riskier patients to higher levels-of-care. This study examined whether "lemon-dropped" primary total joint arthroplasty (pTJA) patients require increased health care resources and experience worse outcomes.

METHODS

This was a retrospective cohort study of all pTJAs at one tertiary care center in 2022, excluding bilaterals, acute fractures, oncologic cases, and conversion hips. Patients were classified via referral pattern as simple or complex (referred for medical or surgical complexity). Primary outcomes were implant costs and any emergency department visit, readmission, reoperation, or complication within 90 days. Secondary outcomes were distance traveled to the hospital, anesthesia type, estimated blood loss, case duration, time in the recovery unit, length of stay, and discharge disposition. Outcomes were assessed via electronic medical record review and analyzed via Fisher's exact and unpaired Welch's t-tests.

RESULTS

In total 641 pTJAs (322 hips, 319 knees) met inclusion criteria; 10.3% were complex referrals. Complex patients were younger (59 versus 66 years, P < .05) and more often non-White (41 versus 31%, P < .001), non-English speaking (11 versus 7%, P < .001), and had nonprimary osteoarthritis as a surgical indication (59 versus 12%, P < .001), but had similar Charlson Comorbidity Index and American Society of Anesthesiologists scores. Complex patients had increased odds of 90-day emergency department visits (OR [odds ratio] = 2.11, P = .04), 90-day complications (OR = 2.63, P < .001), and non-home discharge (OR = 2.60, P = .006); higher mean relative implant costs (1.31x, P < .001); longer time in the operating room (181 versus 158 minutes P < .001), time in surgery (125 versus 105 minutes, P < .001), and length of stay (3.2 versus 1.7 days, P = .005).

CONCLUSIONS

"Lemon-dropped" pTJAs had worse early clinical outcomes and higher health care utilization, despite a control group with patients ill enough to utilize a tertiary care center as their medical home. Reimbursement models and evaluation metrics must account for these differences.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

Increasing the Volume of Outpatient Total Joint Arthroplasty Procedures: An Evaluation of a Novel Rapid Recovery Pathway Program Within an Academic Medical Center

Background

There has been a national trend toward shifting joint arthroplasty procedures to the outpatient setting. These cases are often performed in freestanding ambulatory surgery centers (ASCs), which are often not accessible to surgeons within academic practices.

Purposes

We sought to investigate a novel rapid recovery program used to transition arthroplasty patients to an outpatient-based care system within an academic medical center.

Methods

All patients undergoing hip or knee arthroplasty between November 2019 and April 2021 were retrospectively evaluated for their eligibility for a rapid recovery pathway through the Extended Stay Unit (ESU) based on clinical and social criteria. Once admitted, patients were evaluated for whether they were discharged from the unit or if hospital admission was necessary.

Results

Out of the 444 patients deemed candidates for the rapid recovery program, 188 patients were admitted to the ESU (42.3%); 18 (9.6%) required inpatient hospital admission, with the majority of these due to failing physical therapy (16; 88.9%). Of the ESU patients who were successfully discharged home, 55 (32.4%) were discharged on postoperative day (POD) 0 and 115 (67.6%) on POD 1 (<23 hours).

Conclusion

As total joint arthroplasties shift toward the outpatient setting, surgeons in academic institutions must employ strategies to increase their volume of patient candidates for outpatient procedures. Our retrospective study of prospectively collected data suggests the feasibility of creating a separate rapid recovery unit within the hospital that can be an effective method by which to eventually transition to the ASC setting.

Influence of Demographic and Socioeconomic Factors on Hospital Distance for Total Knee Arthroplasty

Background

Disparities exist in access to and outcomes following total knee arthroplasty. However, there is a paucity of data examining the relationship between travel distance and these disparities.

Methods

We used the Healthcare Cost and Utilization Project, American Hospital Association, and UnitedStatesZipCodes.org Enterprise databases to gather patient demographic and postoperative outcomes data. We calculated the distance traveled between patient population-weighted zip code centroid points and the hospitals at which they received total knee arthroplasty. We then examined the association between travel distance and patient demographic characteristics as well as postoperative adverse outcomes.

Results

Among of cohort of 384,038 patients, white patients (16.58 miles) traveled farther on average than Black (10.05) or Hispanic patients (10.54) (P < .0001). Medicare and commercial insurance coverage were associated with greater travel distance (P < .0001). Fewer medical comorbidities (P < .001) and residence in the highest-income areas (P < .0001) were associated with increased travel distance. Differences in postoperative complication rates related to travel distance were not clinically significant.

Conclusions

Increased travel distance for total knee arthroplasty was associated with white race, commercial and Medicare insurance coverage, fewer medical comorbidities, and increased socioeconomic status. Future work is needed to determine the underlying causal mechanisms leading to these differences in access to specialized care.

Taking the Long Way to Care: Who is Traveling Farthest to Undergo Elective Total Hip Arthroplasty?

Background

Disparities in access to total hip arthroplasty (THA) exist. The purpose of this study is to examine how distance traveled to undergo elective THA correlates with sociodemographic variables and postoperative outcomes.

Material and methods

The Healthcare Cost and Utilization Project New York and Florida state inpatient databases were used to identify patients who underwent elective THA between 2006 and 2014. Data from the American Hospital Association and United States Postal Service were used to calculate the distance patients traveled to receive THA, and only those who traveled more than 25 miles were included. We stratified patients into 4 groups based on their distance traveled (25-50 miles, 50.01-100 miles, 100.01-500 miles, and >500.01 miles) and compared demographic characteristics and postoperative outcomes between groups.

Results

Age, race, insurance provider, zip code income quartile, and Charlson Comorbidity Index scores were each significantly associated with travel distance (P < .001) among our cohort of 25,734 patients. Patients who were older, were white, had Medicare insurance coverage, lived in zip codes with a higher median household income, and had increased comorbidities were more likely to travel the farthest to receive care. There were minimal associations between travel distance and postoperative outcomes.

Conclusion

There may be specific demographic groups who either are forced to travel long distances to receive care or have the resources to seek out and travel to distant hospitals in an effort to receive optimal care. Understanding the interconnected relationships between demographic variables is necessary to address disparities in access to specialized orthopedic surgical care.

Demographics of Patients Traveling Notable Distances to Receive Total Knee Arthroplasty

Although disparities exist in patient access to and outcomes after total knee arthroplasty (TKA), there are limited data regarding the relationship between travel distance and patient demographics or postoperative complications.

Analysis of patient characteristics and outcomes related to distance traveled to a tertiary center for primary reverse shoulder arthroplasty

INTRODUCTION

The reasons for referral and travel patterns are lacking for patients undergoing reverse shoulder arthroplasty (RSA). The purpose of this study was to compare comorbidities, surgical time, cost and complications between local and distant primary RSA patients.

METHODS

Between 2007 and 2015, 1,666 primary RSAs were performed at our institution. Patients were divided into two cohorts, local patients (from within Olmstead county and surrounding counties, 492 RSAs) and those from a distance (1,174 RSAs).

RESULTS

Local patients were older (74 vs 71 years, p < .001), more likely to have RSA for fracture, had a higher Charlson comorbidity score (3.8 vs 3.2, p < .001) and longer hospital stays (2.0 vs 1.8 days, p < 0.001) compared to referred patients. Referral patients required longer operative times (95 vs 88 min, p = .002), had higher hospitalization costs ($19,101 vs $18,735, p < .001), and had a higher rate of prior surgery (32% vs 24%, p < .001). There were no differences between cohorts regarding complications or need for reoperation.

CONCLUSIONS

Patients traveling from a distance to undergo primary RSA had longer operative times and were more likely to have had prior surgery than local patients. This may demonstrate the referral bias seen at large academic centers and should be considered when reviewing RSA outcomes, hospital performance, and calculating insurance reimbursement.

LEVEL OF EVIDENCE

Level IV.

Evaluating Distance Bias in Chronic Rhinosinusitis Outcomes

Importance

The distance traveled by patients for medical care is associated with patient outcomes (ie, distance bias) and is a limitation in outcomes research. However, to date, distance bias has not been examined in rhinologic studies.

Objective

To evaluate the association of distance traveled by a cohort of patients with chronic rhinosinusitis with baseline disease severity and treatment outcomes.

Design, Setting, and Participants

A total of 505 patients with chronic rhinosinusitis were prospectively enrolled in a multi-institutional, cross-sectional study in academic tertiary care centers between April 2011 and January 2020. Participants self-selected continued appropriate medical therapy or endoscopic sinus surgery. The 22-item Sinonasal Outcome Test (SNOT-22) and Medical Outcomes Study Short Form 6-D (SF-6D) health utility value scores were recorded at enrollment and follow-up. Data on the distances traveled by patients to the medical centers, based on residence zip codes, and medical comorbid conditions were collected.

Exposures

Distance traveled by patient to obtain rhinologic care.

Main Outcomes and Measures

SNOT-22 and SF-6D scores. Scores for SNOT-22 range from 0 to 110; and for SF-6D, from 0.0 to 1.0. Higher SNOT-22 total scores indicate worse overall symptom severity. Higher SF-6D scores indicate better overall health utility; 1.0 represents perfect health and 0.0 represents death.

Results

The median age for the 505 participants was 56.0 years (IQR, 41.0-64.0 years), 261 were men (51.7%), 457 were White (90.5%), and 13 were Hispanic or Latino (2.6%). These categories were collected according to criteria described and required by the National Institutes of Health and therefore do not equal the entire cohort. Patients traveled a median distance of 31.6 miles (50.6 km) (IQR, 12.2-114.5 miles [19.5-183.2 km]). Baseline (r = 0.00; 95% CI, 0.00-0.18) and posttreatment (r = 0.01; 95% CI, -0.07 to 0.10) SNOT-22 scores, as well as baseline (r = -0.12; 95% CI, -0.21 to -0.04) and posttreatment (r = 0.07; 95% CI, -0.02 to 0.16) SF-6D scores, were not associated with distance. There was no clinically meaningful correlation between distance traveled and mean comorbidity burden. Nevertheless, patients with a history of endoscopic sinus surgery were more likely to travel longer distances to obtain care (Cliff delta = 0.28; 95% CI, 0.19-0.38).

Conclusions and Relevance

Although this cross-sectional study found that some patients appear more willing to travel longer distances for chronic rhinosinusitis care, results suggest that distance traveled to academic tertiary care centers was not associated with disease severity, outcomes, or comorbidity burden. These findings argue for greater generalizability of study results across various cohorts independent of distance traveled to obtain rhinologic care.

Trial Registration

ClinicalTrials.gov Identifier: NCT02720653.

Racial and Socioeconomic Differences in Distance Traveled for Elective Hip Arthroplasty

Introduction:

There are data that disparities exist in access to total hip arthroplasty (THA). However, to date, no study has examined the relationship between distance traveled to undergo THA and patient demographic characteristics, such as race, insurance provider, and income level as well as postoperative outcomes.

Methods:

Data from the Healthcare Cost and Utilization Project, American Hospital Association, and the United States Postal Service were used to calculate the geographic distance between 211,806 patients' population-weighted zip code centroid points to the coordinates of the hospitals at which they underwent THA. We then used Healthcare Cost and Utilization Project data to examine the relationships between travel distance and both patient demographic indicators and postoperative outcomes after THA.

Results:

White patients traveled farther on average to undergo THA as compared with their non-White counterparts (17.38 vs 13.05 miles) (P < 0.0001). Patients with commercial insurance (17.19 miles) and Medicare (16.65 miles) traveled farther on average to receive care than did patients with Medicaid insurance coverage (14.00 miles) (P = 0.0001). Patients residing in zip codes in the top income quartile traveled farther to receive care (18.73 miles) as compared with those in the lowest income quartile (15.31 miles) (P < 0.0001). No clinically significant association was found between travel distance and adverse postoperative outcomes after THA.

Discussion:

Race, insurance provider, and zip code income quartile are associated with differences in the distance traveled to undergo THA. These findings may be indicative of underlying disparities in access to care across patient populations.

Revision Total Joint Arthroplasty: Final Stop Tertiary Referral Center

High complication rates associated with revision total knee arthroplasty (TKA) and total hip arthroplasty (THA) may unequally burden tertiary referral centers, which manage medically complex patients. The authors aimed to quantify TKA and THA referral patterns at a tertiary referral center based on travel distance and patient comorbidities. All patients who underwent primary or revision TKA or THA at the investigating institution from 2012 to 2016 were identified. Travel distance was calculated using each patient's home address and stratified into less than 25 miles, 25 to 74 miles, and 75 miles or more. Age, body mass index, Charlson Comorbidity Index, and postoperative clinical data were identified. Patients were analyzed based on procedure performed and travel distance. A total of 4245 procedures were included for analysis (1754 primary TKAs, 432 revision TKAs, 1503 primary THAs, and 556 revision THAs). Patients living 75 miles or more away had significantly higher odds of undergoing revision arthroplasty compared with patients living within 25 miles (knee: odds ratio [OR], 2.43; hip: OR, 2.61; P<.001). Charlson Comorbidity Index did not increase with travel distance. Patients traveling 75 miles or more were more likely to have periprosthetic fracture (OR, 3.91; P=.011) and less likely to have dislocation (OR, 0.54; P=.026) as the surgical indication for revision. Patients referred to a tertiary center were more likely to necessitate revision total joint arthroplasty but did not differ in comorbidity profile compared with local patients. Periprosthetic fracture, a particularly high-risk surgical indication, was overrepresented among referral patients. These data suggest that factors such as underlying diagnosis, but not preoperative medical comorbidities, may influence referral patterns. [Orthopedics. 2021;44(4):e477-e481.].

Migration Patterns for Revision Total Knee Arthroplasty in the United States as Reported in the American Joint Replacement Registry

BACKGROUND

Revision total knee arthroplasty (TKA) is associated with a higher complication rate and a greater cost when compared to primary TKA. Based on patient choice, referral, or patient transfers, revision TKAs are often performed in different institutions by different surgeons than the primary TKA. The aim of this study is to evaluate the effect of hospital size, teaching status, and revision indication on the migration patterns of failed primary TKA in patients 65 years of age and older.

METHODS

All primary and revision TKAs reported to the American Joint Replacement Registry from January 2012 through March 2020 were included and merged with the Centers for Medicare and Medicaid Services database. Migration was defined as a patient having a primary TKA and revision TKA performed at separate institutions by different surgeons.

RESULTS

In total, 9167 linked primary and revision TKAs were included in the analysis. Overall migration rates were significantly higher from small (<100 beds; P = .019), non-teaching institutions (P = .002) driven primarily by patients diagnosed with infection. Infection patients had significantly higher migration rates from small (46.8%, P < .001), non-teaching (43.5%, P < .001) institutions, while migration rates for other causes of revision were statistically similar. Most patients migrated to medium or large institutions (84.7%) for revision TKA rather than small institutions (15.3%, P < .001) and to teaching (78.3%) rather than non-teaching institutions (21.7%, P < .001).

CONCLUSION

There is a diagnosis-dependent referral bias that affects the migration rates of infected primary TKA from small non-teaching institutions leading to a flow of more medically complex patients to medium and large teaching institutions for infected revision TKA.

Risk Adjustment in the California Joint Replacement Registry: Is Patient Complexity Accurately Assessed in Academic Versus Nonacademic Hospitals?

BACKGROUND

We sought to report on the differences in observed versus expected arthroplasty outcomes between academic and nonacademic hospitals in a large joint registry. We utilized the California Joint Replacement Registry's data and risk adjustment model.

METHODS

Observed versus expected hip and knee arthroplasty complications were utilized to assess hospital and surgeon risk-adjusted complication rates (RACRs). Based on a hospital and surgeon RACR, each was assigned a performance rating ("worse," "expected," "better"). Associations between academic status and performance ratings, rates of individual complications, prevalence of risk factors associated with increased complication rates, and differences in complication rates were calculated.

RESULTS

A higher percentage of academic providers had "worse" than expected ratings, whereas a higher percentage of nonacademic providers had "expected" and "better" than expected ratings (P = .011) based on the observed versus expected complication rates. There was a higher incidence of patients with congestive heart failure and an elevated American Society of Anesthesiologists classification in academic institutions (P = .0001). The complication rate was higher in academic institutions for all total knee arthroplasties (P < .0016).

CONCLUSIONS

We identified disparities in RACRs between nonacademic and academic institutions. This may reflect the difficulty of fully adjusting for medical risk and surgical complexity in a large arthroplasty database.

The Effect of Travel Distance on Outcomes for Hip Resurfacing Arthroplasty at a High-Volume Center

Background

Patients are increasingly traveling greater distances to receive care at high-volume centers. The effect of travel distance on patient-reported outcomes after hip resurfacing arthroplasty has not been described.

Methods

Patients undergoing HRA by a single surgeon from January 2007 to April 2018 with minimum 2-year follow-up were reviewed retrospectively. Five hundred ninety-nine patients were identified and divided into 2 cohorts: home-to-hospital distance >100 miles and ≤100 miles from our institution. Preoperative and 2-year postoperative patient-reported outcome measures (PROMs) were assessed, including the modified Harris Hip Score and Hip disability and Osteoarthritis Outcome Score. The minimal clinically important difference (MCID) for each PROM was calculated using the distribution-based method. Chi-square tests were used for univariate comparison. Poisson regressions controlling for demographic variables were performed to determine the effect of travel distance on whether patients achieved the MCID. Multivariate linear regressions were used to determine association between distance and improvement in PROMs.

Results

A total of 599 patients met criteria for inclusion. There were 113 (18.9%) with a home-to-hospital distance >100 miles and 486 (81.1%) with distance ≤100 miles. Age was the only demographic factor different between these groups (mean: 1.1-year difference, P < .001). There were no significant differences in reaching the MCID on any PROM between these groups. Multivariate linear regressions revealed no associations between travel distance and improvement in PROMs.

Conclusions

Travel distance to a high-volume center did not affect 2-year patient-reported outcomes or rate of achieving the MCID in patients undergoing hip resurfacing arthroplasty.

Does Referral Bias Impact Outcomes of Surgery for Degenerative Mitral Valve Disease?

BACKGROUND

Geographic origin is cited as a possible factor influencing outcomes of operation for repair or replacement of degenerative mitral valve (MV) disease. Our study aimed to identify the potential impact of referral bias on clinical outcomes of MV surgery.

METHODS

We analyzed clinical and echocardiographic information of 2353 patients undergoing primary or secondary MV surgery for degenerative MV disease. Patients were grouped as local (in-state), regional (5 surrounding states), or national referrals.

RESULTS

The number of patients (local, 827; regional, 809; national, 717) and median follow-up time (9.1 years) were similar between geographic groups. More comorbidities were found in the local patient group. Overall operative risk was 0.7% and was greater in local and regional patients compared with national patients (0.7% and 1.1% vs 0.1%, P = .05). Valve repair was performed in 97% of isolated MV surgeries, and repair rate was similar in the 3 geographic groups. The 3 groups had similar incidences of major morbidity, but local and regional groups had higher 30-day readmissions. In univariate analysis, survival was improved in national and regional patients compared with local patients; however in multivariable analysis this difference was no longer significant.

CONCLUSIONS

There were important variations in baseline demographic and clinical characteristics between referral groups; local and regional patients presented with more comorbid conditions compared with national referrals. Aside from a small difference in perioperative mortality, early outcomes were generally similar. Late survival, however, was superior in national patients, and this referral bias is explained by fewer associated medical illnesses.

Travel Distance Does Not Affect Outcomes in Hip Preservation Surgery: A Case for Centers of Excellence

Background:

Previous studies have evaluated the effect of distance to high-volume centers on outcomes after joint replacement. However, there is limited evidence on whether this distance has an effect on outcomes after undergoing hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS).

Purpose:

To determine whether increased distance from a patient’s home to his or her primary orthopaedic clinic has an influence on the ability to achieve the minimal clinically important difference (MCID) on outcome measures after surgery for FAIS.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective cohort analysis was performed on patients undergoing surgery for FAIS by a single surgeon from January 2012 through January 2017. A total of 692 patients were identified and split into 2 groups: driving distance of <50 miles from our institution (referral group) and driving distance of <50 miles from our institution (local group). Preoperative and 2-year postoperative scores on patient-reported outcome measures (PROMs), including the Hip Outcome Score Activities of Daily Living and Sport-Specific subscales, International Hip Outcome Tool–12, and modified Harris Hip Score, were assessed. Patients achieving the MCID on any included PROM were analyzed using a chi-square analysis. Logistic regression was performed to determine whether driving distance and other demographic variables of interest had an effect on achieving the MCID. Study data were analyzed using PatientIQ, a cloud-based research and analytics platform for health care.

Results:

There were 647 patients who completed 2-year follow-up and were included in the analysis. Of these patients, 116 (17.9%) were identified as being ≥50 miles from their orthopaedic provider, and 531 (82.1%) were identified as having a driving distance of <50 miles. A total of 100 patients (86.2%) in the referral group reached the MCID, and 476 patients (89.6%) in the local group reached the MCID. There was no statistically significant difference in reaching the MCID on any of the included PROMs between the 2 groups (P = .364). The same result held when controlling for a number of factors including age, body mass index, and adjusted gross income with logistic regression.

Conclusion:

When controlling for a number of factors including age, body mass index, and adjusted gross income, distance to a high-volume hip arthroscopic surgery center did not have an effect on postoperative outcome scores or achieving the MCID 2 years after undergoing surgery for FAIS.