All-Cause Versus Complication-Specific Readmission Following Total Knee Arthroplasty

Characterization of Re-admission and Emergency Department Visits Within 90 Days Following Lower-Extremity Arthroplasty

BACKGROUND

Acute care events including emergency department (ED) visits and unscheduled inpatient re-admissions following lower-extremity arthroplasty are not fully understood.

QUESTION/PURPOSES

The purpose of this study was to characterize acute care events occurring after discharge in patients who received a lower-extremity arthroplasty: the incidence, timing, and risk factors of inpatient admission and ED visits within 90 days of discharge.

METHODS

The New York State Inpatient and Emergency Department Databases were used to identify patients who underwent elective total knee arthroplasty (TKA) or total hip arthroplasty (THA) from 2009 to 2013 (124,234 and 76,411 patients, respectively). Multivariate logistic regression analysis was used to determine the predictors of and the most frequent reasons for unscheduled acute care within 90 days of discharge.

RESULTS

Unscheduled acute care was needed in 13.79% of patients (8.81% of inpatient re-admissions and 4.98% of ED visits), most often in the first week after discharge (61.05% of all inpatient re-admissions and 20.46% of all ED visits). Most of these visits were for musculoskeletal pain, peri-prosthetic joint or wound infection, cardiac complications, blood transfusion, psychiatric events, mechanical complications, and deep vein thrombosis. Predictors for the need for acute care after TKA included African American and Hispanic race or ethnicity, Medicaid coverage, and neuraxial anesthesia. Predictors for the need for acute care after THA included older age (over 85 years), African American race, and Medicaid coverage.

CONCLUSION

We identified demographic and procedure-related variables associated with an increased risk of ED visits and inpatient re-admissions after TKA or THA. Understanding these variables will contribute to improved care quality.

Predictors and Cost of Readmission in Total Knee Arthroplasty

BACKGROUND

The Comprehensive Care for Joint Replacement bundle was created to decrease total knee arthroplasty (TKA) cost. To help accomplish this, there is a focus on reducing TKA readmissions. However, there is a lack of national representative sample of all-payer hospital admissions to direct strategy, identify risk factors for readmission, and understand actual readmission cost.

METHODS

We used the Nationwide Readmission Database to examine national readmission rates, predictors of readmission, and associated readmission costs for elective TKA procedures. We fit a multivariable logistic regression model to examine factors associated with readmission. Then, we determined mean readmission costs and calculated the readmission cost when distributed across the entire TKA population.

RESULTS

We identified 224,465 patients having TKA across all states participating in the Nationwide Readmission Database. The mean unadjusted 30-day TKA readmission rate was 4%. The greatest predictors of readmission were congestive heart failure (odds ratio [OR] 2.51, 95% confidence interval [CI] 2.62-2.80), renal disease (OR 2.19, 95% CI 2.03-2.37), and length of stay greater than 4 days (OR 2.4, 95% CI 2.25-2.61). The overall median cost for each readmission was $6753 ± 175. Extrapolating the readmission cost for the entire TKA population resulted in the readmission cost being 2% of the overall 30-day procedure cost.

CONCLUSIONS

A major focus of the Comprehensive Care for Joint Replacement bundle is improving cost and quality by limiting readmission rates. TKA readmissions are low and comprise a small percentage of total TKA cost, suggesting that they may not be the optimal measure of quality care or a significant driver of overall cost.

Reducing Length of Stay Does Not Increase Emergency Room Visits or Readmissions in Patients Undergoing Primary Hip and Knee Arthroplasties

BACKGROUND

Total hip and total knee arthroplasty (total joint arthroplasty [TJA]) are 2 of the most common elective surgeries. Identifying which patients are at highest risk for emergency room (ER) visits or readmissions within 90 days of surgery and the reasons for return are crucial to formulate ways to decrease these visits and improve patient outcomes.

METHODS

This is a retrospective review of a consecutive series of 7466 unilateral primary TJA performed from July 2013 to June 2017; any patients who had an ER visit or readmission in the first 90 days after surgery were identified, and a detailed chart review was performed. Patients discharged home or to rehab were analyzed separately.

RESULTS

Three hundred thirty-six (4.5%) patients had 380 ER visits and 250 (3.3%) patients had 291 readmissions in the first 90 days after TJA. Patients returning to the ER were equivalent to those who did not. Patients who went to a rehab facility on discharge were significantly more likely to be readmitted (P = .000). Patients who were readmitted had a higher American Society of Anesthesiologists score (P = .000). Length of stay decreased over the study period from 2.66 days to 1.63 days, while the number of unplanned interventions remained steady. Pain and swelling was the most common reason for return for ER visits (33.2%) and readmissions (14.1%).

CONCLUSION

The overall number of unplanned interventions after TJA in this population was low and remained consistent over time despite decreasing length of stay. Patients who went to rehab were more likely to experience readmission. The majority of unplanned interventions occurred in the first 4 weeks after surgery.

Risk Adjustment Is Necessary in Medicare Bundled Payment Models for Total Hip and Knee Arthroplasty

BACKGROUND

Concerns exist that high-risk patients in alternative payment models may face difficulties with access to care without proper risk adjustment. The purpose of this study is to identify the effect of medical and orthopedic specific risk factors on the cost of a 90-day episode of care following total hip (THA) and knee arthroplasty (TKA).

METHODS

We queried the Medicare 5% Limited Data Set for all patients undergoing primary THA and TKA from 2010 to 2014. To evaluate the cost of an episode of care, we calculated all claims for 90 days following surgery. Multivariate analysis was performed to quantify the added episode-of-care costs for demographic variables, geography, medical comorbidities, and orthopedic specific risk factors.

RESULTS

Of the 58,809 TKA patients, the median 90-day Medicare costs was $23,800 (interquartile range, $18,900-$32,300), while the median of the 27,293 THA patients was $24,000 (interquartile range, $18,500-$33,900). Independent risk factors (all P < .05) resulting in at least a 10% increase in episode-of-care costs following TKA included malnutrition, age over 85, male gender, pulmonary disorder, failed internal fixation, Northeast region, lower socioeconomic status, neurologic disorder, and rheumatoid arthritis. Independent risk factors (all P < .05) resulting in at least a 10% increase in episode-of-care costs following THA included malnutrition, male gender, age over 85, failed internal fixation, hip dysplasia, Northeast region, neurologic disorder, lower socioeconomic status, conversion THA, avascular necrosis, and depression.

CONCLUSION

Certain comorbidities and orthopedic risk factors increase 90-day episode-of-care costs in the Medicare population. The current lack of proper risk stratification could be a powerful driver of decreased access to care for our most medically challenged members of society.