Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are currently grouped under the same Diagnosis-Related Group (DRG). With the introduction of bundled payments, providers are accountable for all the costs incurred during the episode of care, including the costs of readmissions and management of complications. However, it is unclear whether readmission rates and short-term complications are similar in primary THA and TKA.
The National Surgical Quality Improvement Project database was queried from 2011 to 2015 to identify 248,150 primary THA/TKA procedures using Current Procedural Terminology codes. After excluding 1602 hip fractures and 5062 bilateral procedures, 94,326 THAs and 147,160 TKAs were included in the study. Length of stay, discharge disposition, and 30-day readmission, reoperation and complication rates were compared between THA and TKA using multivariate regression models.
After adjusting for baseline characteristics, length of stay (P = .055) and discharge disposition (P = .304) were similar between THA and TKA. But the 30-day rates of readmission (P < .001) and reoperation (P < .001) were higher in THA. Of the 18 complications evaluated in the study, 7 were higher in THA, 3 were higher in TKA, and 8 were similar between THA and TKA.
THA patients had higher 30-day rates of readmission and reoperation. As both readmissions and reoperations can result in higher episode costs, a common target price for both THA and TKA may be inappropriate. Further studies are required to fully understand the extent of differences in the episode costs of THA and TKA.