How Much Does a Readmission Cost the Bundle Following Primary Hip and Knee Arthroplasty?

As alternative payment models increase in popularity for total joint arthroplasty (TJA), providers and hospitals now share the financial risk associated with unexpected readmissions. While studies have identified postacute care as a driver for costs in a bundle, the fiscal burden associated with specific causes of readmission is unclear. The purpose of this study is to quantify the additional costs associated with each of the causes of readmission following primary TJA.

We reviewed a consecutive series of primary TJA patients at our institution from 2015 to 2016 using claims data from the Centers for Medicare and Medicaid Services and Medicare Advantage patients from a single private insurer. We collected demographic data, medical comorbidities, 90-day episode-of-care costs, and readmissions for all patients. Medical records for each readmission were reviewed and classified into 1 of 11 categories. We then compared the mean facility readmission costs, postacute care costs, and overall 90-day episode-of-care costs between the reasons for readmission.

Of the 4704 patients, there were 325 readmissions in 286 patients (6.1%), with 50% being readmitted to a different facility than their index surgery hospital. The mean additional cost was $8588 per readmission. Medical reasons accounted for the majority of readmissions (n = 257, 79.1%). However, patients readmitted for revision surgery (n = 68, 20.9%) had the highest mean readmission cost ($15,356, P < .001). Furthermore, readmissions for revision surgery had the highest mean postacute care ($37,207, P = .002) and overall episode-of-care costs ($52,162, P = .003). Risk factors for readmission included age >75 years (odds ratio [OR], 1.85; P < .001), body mass index >35 kg/m² (OR, 1.63; P = .004), history of congestive heart failure (OR, 2.47; P = .002), diabetes mellitus (OR, 2.0; P < .001), and renal disease (OR, 2.28; P = .005).

Providers participating in alternative payment models should be cognizant of the increased bundle costs attributed to readmissions, especially due to revision surgery. Improved communication with patients and close postoperative monitoring may help minimize the large percentage of readmissions at different facilities.