Reasons for Ninety-Day Emergency Visits and Readmissions After Elective Total Joint Arthroplasty: Results From a US Integrated Healthcare System

Background

Previous studies evaluating reasons for 30-day readmissions following total joint arthroplasty (TJA) may underestimate hospital-based utilization of healthcare resources during a patient's episode-of-care. We sought to identify common reasons for 90-day emergency department (ED) visits and hospital readmissions following primary elective unilateral TJA.

How Accurately Are We Coding Readmission Diagnoses After Total Joint Arthroplasty?

Readmission rates have been cited as an important quality measure in the Affordable Care Act. Accordingly, understanding and accurately tracking the causes for readmission will be increasingly important. We queried an electronic database for all patients who underwent primary THA or TKA at our institution from 2006 through 2010. We identified those readmitted within 90 days of surgery and analyzed 87 random de-identified medical records. We then assigned a clinical diagnosis for each readmission, which was then compared with the coder-derived diagnosis by ICD-9 code. The overall 90-day readmission rate was 7.9%. We identified 22 of 87 patients for whom there was disagreement (25.3%, 95% CI = 16.6–35.8%). The most common were procedure-related complications. Coded diagnoses frequently did not correlate with the physician-derived diagnoses. The unverified use of coded readmission diagnoses in calculating quality measures may not be clinically relevant.     

The Effect of Discharge Disposition on 30-Day Readmission Rates After Total Joint Arthroplasty

Previous studies have demonstrated no significant difference in overall functional outcomes of patients discharged to a sub acute setting versus home with health services after total joint arthroplasty. These findings coupled with pressure to reduce health care costs and the implementation of a prospective payment system under Medicare have supported the use of home rehabilitation services and the trend towards earlier discharge after hospitalization. While the overall functional outcome of patients discharged to various settings has been studied, there is a relative dearth of investigation comparing postoperative complications and readmission rates between various discharge dispositions. Our study demonstrated patients discharged home with health services had a significantly lower 30 day readmission rate compared to those discharged to inpatient rehab facilities. Patients discharged to rehab facilities have a higher incidence of comorbidity and this association could be responsible for their higher rate of readmission.     

Preoperative Malnutrition Negatively Correlates With Postoperative Wound Complications and Infection After Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

Background

Malnutrition continues to be prevalent in the general population. A variety of studies have correlated poor nutritional status with reduced perioperative outcomes. However, the correlation between serologic malnutrition and arthroplasty outcomes has not been systematically evaluated. The purpose of this study was to determine if serologic malnutrition has a correlation with postoperative wound infection, as well as other complications, after total joint arthroplasty.

Optimal Length of Stay Following Total Joint Arthroplasty to Reduce Readmission Rates

BackgroundLength of stay (LOS) following total joint arthroplasty (TJA) continues to decrease. The effects of this trend on readmission risk and total cost are unclear. We hypothesize that optimal LOS following TJA minimizes index hospitalization, early readmission risk, and total cost.MethodsRetrospective data from the South Carolina Department of Revenue and Fiscal Affairs was reviewed for patients who underwent primary TJA in South Carolina from 2000 to 2015 (n = 172,760). Data for readmissions within 90 days were included. Severity of illness was estimated by Elixhauser score (EH). Index LOS is defined as the surgery and the subsequent hospital stay.ResultsPatients with more significant medical comorbidities (EH ≥ 4) had significantly longer LOS than healthier patients (4.0 vs 3.4 days, P < .001). Independent of EH, readmitted patients had a significantly longer index LOS than those never readmitted (4.3 vs 3.6 days, P < .001). For healthier patients (EH ≤ 3), each additional inpatient day increased readmission risk, while among sicker patients, staying 2 days vs 1 day was protective against readmission risk. Since 2000, the total index cost of TJA has doubled and average cost per inpatient day has tripled, but readmission rates remain essentially unchanged (7.4% to 7.0%).ConclusionIncreased LOS was associated with increased readmission risk. Patients with greater medical comorbidities stay longer to protect against readmission. Optimal LOS after TJA is highly influenced by the patient’s overall health. Despite a 300% increase in TJA daily cost, readmission rate has changed minimally over the last 15 years.     

Sleep Apnea Increases Ninety-Day Complications and Cost Following Primary Total Joint Arthroplasty

Background

Sleep apnea (SA) negatively affects bone mineralization, cognition, and immunity. There is paucity in the literature regarding the impact of SA on total joint arthroplasty (TJA). The purpose of this study is to compare complications in patients with and without SA undergoing either total knee (TKA) or total hip arthroplasty (THA).

Skilled Nursing Facility Star Rating,Patient Outcomes,and Readmission Risk After Total Joint Arthroplasty

Background

This study examined the correlation between publicly reported indicators of skilled nursing facility (SNF) quality and clinical outcomes after primary total knee arthroplasty (TKA) and total hip arthroplasty (THA).

The Cost-Effectiveness of Silver-Impregnated Occlusive Dressings for Infection Prevention After Total Joint Arthroplasty

BackgroundProsthetic joint infection (PJI) is a catastrophic complication after total joint arthroplasty that exacts a substantial economic burden on the health-care system. This study used break-even analysis to investigate whether the use of silver-impregnated occlusive dressings is a cost-effective measure for preventing PJI after primary total knee arthroplasty (TKA) and total hip arthroplasty (THA).MethodsBaseline infection rates after TKA and THA, the cost of revision arthroplasty for PJI, and the cost of a silver-impregnated occlusive dressing were determined based on institutional data and the existing literature. A break-even analysis was then conducted to calculate the minimal absolute risk reduction needed for cost-effectiveness.ResultsThe use of silver-impregnated occlusive dressings would be economically viable at an infection rate of 1.10%, treatment costs of $25,692 for TKA PJI, and $31,753 for THA PJI and our institutional dressing price of $38.05 if it reduces infection rates after TKA by 0.15% (the number needed to treat [NNT] = 676) and THA by 0.12% (NNT = 835). The absolute risk reduction needed to maintain cost-effectiveness did not change with varying initial infection rates and remained less than 0.40% (NNT = 263) for infection treatment costs as low as $10,000 and less than 0.80% (NNT = 129) for dressing prices as high as $200.ConclusionThe use of silver-impregnated occlusive dressings is a cost-effective measure for infection prophylaxis after TKA and THA.     

Assessment of a Satisfaction Measure for Use After Primary Total Joint Arthroplasty

BackgroundPatient satisfaction after total hip (THA) and total knee arthroplasty (TKA) is a core outcome selected by the Outcomes Measurement in Rheumatology. Up to 20% of THA/TKA patients are dissatisfied. Improving patient satisfaction is hindered by the lack of a validated measurement tool that can accurately measure change.MethodsThe psychometric properties of a proposed satisfaction instrument, consisting of 4 questions rated on a Likert scale, scored 1-100, were tested for validity, reliability, and sensitivity to change using data collected between 2007 and 2011 in an arthroplasty registry.ResultsWe demonstrated construct validity by confirming our hypothesis; satisfaction correlated with similar constructs. Satisfaction correlated moderately with pain relief (TKA ρ = 0.61, THA ρ = 0.47) and function (TKA ρ = 0.65, THA ρ = 0.51) at 2 years; there was no correlation with baseline/preoperative pain/function values, as expected. Overall Cronbach’s alpha >0.88 confirmed internal consistency. Test-retest reliability with weighted kappa ranged 0.60-0.75 for TKA and 0.36-0.56 for THA. Hip disability and Osteoarthritis Outcome Score/Knee injury and Osteoarthritis Outcome Scores quality of life improvement (>30 points) corresponds to a mean satisfaction score of 93.2 (standard deviation, 11.5) after THA and 90.4 (standard deviation, 13.8) after TKA, and increasing relief of pain and functional improvement increased the strength of their association with satisfaction. The satisfaction measure has no copyright and is available free of cost and represents minimal responder burden.ConclusionPatient satisfaction with THA/TKA can be measured with a validated 4-item questionnaire. This satisfaction measure can be included in a total joint arthroplasty core measurement set for total joint arthroplasty trials.     

Improving Orthopedic Patient Outcomes: A Model to Predict 30-Day and 90-Day Readmission Rates Following Total Joint Arthroplasty

BackgroundOver the next 10-15 years, there is expected to be an exponential increase in the number of total joint arthroplasties in the American population. This, combined with rising costs of total joint arthroplasty and more recent changes to the reimbursement payment models, increases the demand to perform quality, cost-effective total joint arthroplasties. The purpose of this study is to build models that could be used to estimate the 30-day and 90-day readmission rates for patients undergoing total joint arthroplasty.MethodsA retrospective review of patients admitted to a single hospital, over the course of 56 months, for total joint arthroplasty was performed. The goal is to identify patients with readmission in a 30-day or 90-day period following discharge from the hospital. Binary logistic regression was used to build predictive models that estimate the likelihood of readmission based on a patient’s risk factors.ResultsOf 5732 patients identified for this study, 237 were readmitted within 30 days, while 547 were readmitted within 90 days. Age, body mass index, gender, discharge disposition, occurrence of cardiac dysrhythmias and heart failure, emergency department visits, psychiatric diagnoses, and medication counts were all found to be associated with 30-day admission rates. Similar associations were found at 90 days, with the exclusion of age and psychiatric drug use, and the inclusion of intravenous drug abuse, narcotic medications, and total joint arthroplasty within 12 months.ConclusionThere are patient variables, or risk factors, that serve to predict the likelihood of readmission following total joint arthroplasty.     

Combined Malnutrition and Frailty Significantly Increases Complications and Mortality in Patients Undergoing Elective Total Hip Arthroplasty

BackgroundThe demand for total hip arthroplasty (THA) continues to rise. While prior work has examined frailty and malnutrition independently, the additive effects of these conditions are unknown. Therefore, the purpose of this study was to evaluate the individual and combined influence of malnutrition and frailty in the elective THA patient.MethodsThis is a retrospective cohort study. Patients undergoing elective, primary THA were identified from the American College of Surgeons-National Surgery Quality Improvement Program database. Patients with hip fracture were excluded. Preoperative serum albumin levels (malnutrition = albumin <3.5 g/dL) and 5-item modified frailty index scores (≥2 = frail) were collected. Four cohorts were created: (1) Healthy (N), (2) Frail-only (F), (3) Hypoalbuminemia-only (H), and (4) Hypoalbuminemia and frail (HF). Demographic and complication data were collected, and statistical analysis was performed comparing complications between cohorts.Results105,997 patients undergoing THA were identified for inclusion. The majority (82%) of patients were healthy (14% F, 3% H, and 1% HF). The HF group was found to have higher odds of complication compared with all other groups (HF vs N; odds ratio [OR] 3.7, 95% confidence interval [CI] 3.07-4.46, P < .001). Notably, patients in the HF cohort had a 1.9% 30-day mortality rate (HF vs N; OR 12.66, 95% CI 7.81-20.83, P < .001). Additionally, HF patients had higher odds of increased resource utilization when compared with all other groups (P < .001).ConclusionsFrailty and malnutrition both represent physiologically compromised states but are only weakly correlated. The concurrent presence of frailty and malnutrition in the THA patient has significant detrimental impacts. Further research will be needed to delineate to what degree these risk factors are modifiable.     

Clinical Pharmacist Service Associated With Improved Outcomes and Cost Savings in Total Joint Arthroplasty

BackgroundInstitutions providing total joint arthroplasty (TJA) procedures are subject to substantial outcomes reporting, including those influencing payment for services. Although clinical pharmacists are well-poised to add value, a comprehensive approach to optimizing pharmacotherapy across the care continuum for TJA patients has not been described.MethodsThis prospective, interventional, sequential cohort study was approved by our Institutional Review Board. The objective was to assess the impact of an Orthopedic Clinical Pharmacist service on institutional TJA complication rates and costs. Outcomes were compared for a Baseline period of July 2015 to February 2016 and a Post-implementation period of September 2016 to February 2017, allowing for a 6-month run-in period. Additionally, we pursued a post-discharge, RN-administered patient survey and an exploratory economic assessment.ResultsA total of 1715 TJA procedures were performed at the institution during the 20-month study timeframe. Postoperative readmission rate (1.3% vs 4.8%, P = .002) and complication rate (1.8% vs 3.4%, P = .760) were lower in the Post-implementation period. Postoperative VTE rate decreased to zero in the Post-implementation period (0.0% vs 0.6%, P = .13) and average hospital length of stay was unchanged (2.8 vs 2.9 days). Patient self-rated understanding of discharge medications was improved and satisfaction with pharmacist interaction was very high. The service conferred an estimated $73,410 net annual cost savings to the institution.ConclusionIntegration of a clinical pharmacist service for TJA patients was associated with clinically meaningful improvements in institutional outcomes, likely conferring substantial cost-benefit.     

A Fall Within 3 Months Before Total Joint Arthroplasty is Associated With Adverse Outcomes in Elderly Patients

BackgroundFalls are associated with morbidity and death in the elderly. The consequences of falls after total joint arthroplasty (TJA) are known, but the consequences of preoperative falls are unclear. We assessed associations between preoperative fall history and hospital readmission rates and discharge disposition after primary TJA.MethodsWe queried the National Surgical Quality Improvement Program Geriatric Pilot Project for cases of primary total hip arthroplasty (THA) (n = 3671) and total knee arthroplasty (TKA) (n = 6194) performed between 2014 and 2018 for patients aged ≥65 years. Patient characteristics, comorbidities, functional status indicators, and 30-day outcomes were compared among patients with falls occurring within 3 months, from >3 to 6 months, and from >6 to 12 months before surgery, and patients with no falls in the year before surgery. The timing of falls was assessed for independent associations with hospital readmission and discharge to a skilled care facility (SCF). Alpha = 0.05.ResultsPatients who fell within 3 months before surgery had greater odds of SCF discharge (for THA, odds ratio [OR] 2.5, 95% confidence interval [CI] 1.8-3.4; for TKA, OR 1.8, 95% CI 1.4-2.3) and hospital readmission (for THA, OR 1.8, 95% CI 1.1-3.0; for TKA, OR 2.4, 95% CI 1.6-3.5) compared with the no-fall cohort. No such associations were observed for the other two fall cohorts.ConclusionFalls within 3 months before primary TJA are associated with SCF discharge and readmission for patients aged ≥65 years. Fall history screening should be included in preoperative evaluation.Level of EvidenceIII.     

Relative Contribution of Outpatient Arthroplasty Risk Assessment Score Medical Comorbidities to Same-Day Discharge After Primary Total Joint Arthroplasty

BackgroundSelection of patients who can safely undergo outpatient total joint arthroplasty (TJA) is an increasing priority given the growth of ambulatory TJA. This study quantified the relative contribution and weight of 52 medical comorbidities comprising the Outpatient Arthroplasty Risk Assessment (OARA) score as predictors of safe same-day discharge (SDD).MethodsThe medical records of 2748 primary TJAs consecutively performed between 2014 and 2020 were reviewed to record the presence or absence of medical comorbidities in the OARA score. After controlling for patients not offered SDD due to OARA scores and patients who were offered but declined SDD, the final analysis sample consisted of 631 cases, 92.1% of whom achieved SDD and 7.9% of whom did not achieve SDD. Odds ratios were calculated to quantify the extent to which each comorbidity is associated with achieving SDD.ResultsDemographic characteristics of analysis cases were consistent with a high-volume TJA practice in a US metropolitan area. Among testable OARA comorbidities, 53% significantly decreased the likelihood of SDD by 2.3 (body mass index [BMI] ≥40 kg/m²) to 12 (history of post-operative confusion and pacemaker dependence) times. BMI between 30 and 39 kg/m² did not affect the likelihood of SDD (P = .960), and BMI ≥40 kg/m² had the smallest odds ratio in our study (2.28, 95% confidence interval 1.11-4.67, P = .025).ConclusionStudy findings contribute to the refinement of the OARA score as a successful predictor of safe SDD following primary TJA while maintaining low 90-day readmission rates.     

The Effect of Joint Line Elevation on Patient-Reported Outcomes After Contemporary Revision Total Knee Arthroplasty

BackgroundJoint line elevation in revision total knee arthroplasty (rTKA) is considered a risk factor for inferior outcomes, engendering a dogmatic protocol of joint line restoration. However, this precedent is based on historical data using rudimentary revision systems and unvalidated outcome measures. This study’s purpose was to evaluate the effect of joint line height elevation on validated patient-reported outcome measures (PROMs) using modern revision implants.MethodsA total of 327 rTKAs performed at a single institution were reviewed. Surgical technique prioritized flexion-extension gap balancing and accepted joint line elevation if necessary to achieve a balanced flexion space. Radiographic measurements included changes in joint line height (from preoperative and calculated “intended” anatomic/native) and change in posterior condylar offset. Prospectively collected PROMs were evaluated using multivariate regression.ResultsThe mean joint line elevation from preoperative and “intended” to postoperative joint line was 4.9 ± 5.7 mm and 7.2 ± 6.6 mm, respectively. The mean increase in posterior condylar offset was 1.0 ± 4.6 mm. Patients within ±5 mm of preoperative joint line height were 3.88× more likely to achieve the substantial clinical benefit for Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (P = .004). An increase from intended joint line height >5 mm was not associated with differences in any other PROMs (P ≥ .165).ConclusionsIn contemporary rTKA, recreating the joint line within 5 mm of preoperative improves knee-specific health outcomes. These data support approximating native joint line height as a viable technique to optimize flexion gap balance and subsequent patient outcomes in rTKA.Level of EvidenceLevel III retrospective cohort study.     

Perception of a Natural Joint After Total Knee Arthroplasty

BackgroundAssessing patients’ functional outcomes following total knee arthroplasty (TKA) with traditional scoring systems is limited by their ceiling effects. Patient’s Joint Perception (PJP) question of the reconstructed joint is also of significant interest. Forgotten Joint Score (FJS) was created as a more discriminating option. The actual score constituting a “forgotten joint” has not yet been defined. The primary objective of this study is to compare the PJP and the FJS in TKA patients to determine the FJS score that corresponds to the patient’s perception of a natural joint.MethodsOne hundred TKAs were assessed at a mean of 40.6 months of follow-up using the PJP question, FJS, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Correlation between the 3 scores and their ceiling effects were analyzed.ResultsWith PJP question, 39% of the patients perceived a natural joint (FJS: 92.9; 95% confidence interval [CI], 89.4-96.4), 12% an artificial joint with no restriction (FJS: 79.5; 95% CI, 65.7-93.3), 36% an artificial joint with minor restrictions (FJS: 70.0; 95% CI, 63.2-76.9), and 13% had major restrictions (FJS: 47.3; 95% CI. 32.8-61.7). PJP has a high correlation with FJS and WOMAC (Spearman’s rho, −0.705 and −0.680, respectively). FJS and WOMAC had a significant ceiling effect with both reaching the best possible score in >15%.ConclusionPatients perceiving their TKA as a natural knee based on PJP have a FJS ≥89. PJP has a good correlation with FJS and may be a shorter, simple, and acceptable alternative.     

Differences in Reported Outcomes in Industry-Funded vs Nonfunded Studies Assessing Thromboprophylaxis After Total Joint Arthroplasty

Background

There are numerous studies discussing thromboprophylaxis after total joint arthroplasty (TJA), with varying conclusions. Patient inclusion criteria may be different for each study, which may lead to selection bias and misrepresentation of data. This study aimed to investigate if industry funding impacted patient demographics and overall reported outcomes of studies analyzing venous thromboembolism (VTE) prevention after TJA.

The Cost of Stiffness After Total Knee Arthroplasty

BackgroundStiffness after primary total knee arthroplasty (TKA) is debilitating and poorly understood. A heterogenous approach to the treatment is often utilized, including both nonoperative and operative treatment modalities. The purpose of this study was to examine the prevalence of treatments used between stiff and non-stiff TKA groups and their financial impact.MethodsAn observational cohort study was conducted using a large database. A total of 12,942 patients who underwent unilateral primary TKA from January 1, 2017, to December 31, 2017, were included. Stiffness after TKA was defined as manipulation under anesthesia and a diagnosis code of stiffness or ankylosis, and subsequent diagnosis and procedure codes were used to identify the prevalence and financial impact of multiple common treatment options.ResultsThe prevalence of stiffness after TKA was 6.1%. Stiff patients were more likely to undergo physical therapy, medication, bracing, alternative treatment, clinic visits, and reoperation. Revision surgery was the most common reoperation in the stiff TKA group (7.6%). The incidence of both arthroscopy and revision surgery were higher in the stiff TKA population. Dual component revisions were costlier for patients who had stiff TKAs ($65,771 versus $48,287; P < .05). On average, patients who had stiffness after TKA endured costs from 1.5 to 7.5 times higher than the cost of their non-stiff counterparts during the 2 years following index TKA.ConclusionPatients who have stiffness after primary TKA face significantly higher treatment costs for both operative and nonoperative treatments than patients who do not have stiffness.