, Volume 470, Issue 1, pp 166-171
Date: 01 Jul 2011

Decreased Length of Stay After TKA Is Not Associated With Increased Readmission Rates in a National Medicare Sample

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There is a trend toward decreasing length of hospital stay (LOS) after TKA although it is unclear whether this trend is detrimental to the overall postoperative course. Such information is important for future decisions related to cost containment.


We determined whether decreases in LOS after TKA are associated with increases in readmission rates.

Patients and Methods

We retrospectively reviewed the rates and reasons for readmission and LOS for 4057 Medicare TKA patients from 2002 to 2007. We abstracted data from the Medicare Patient Safety Monitoring System. Hierarchical generalized linear modeling was used to assess the odds of changing readmission rates and LOS over time, controlling for changes in patient demographic and clinical variables.


The overall readmission rate in the 30 days after discharge was 228/4057 (5.6%). The 10 most common reasons for readmission were congestive heart failure (20.4%), chronic ischemic heart disease (13.9%), cardiac dysrhythmias (12.5%), pneumonia (10.8%), osteoarthrosis (9.4%), general symptoms (7.4%), acute myocardial infarction (7.0%), care involving other specified rehabilitation procedure (6.3%), diabetes mellitus (6.3%), and disorders of fluid, electrolyte, and acid-base balance (5.9%); the top 10 causes did not include venous thromboembolism syndromes. We found no difference in the readmission rate between the periods 2002–2004 (5.5%) and 2005–2007 (5.8%) but a reduction in LOS between the periods 2002–2004 (4.1 ± 2.0 days) and 2005–2007 (3.8 ± 1.7 days).


The most common causes for readmission were cardiac-related. A reduction in LOS was not associated with an increase in the readmission rate in this sample. Optimization of cardiac status before discharge and routine primary care physician followup may lead to lower readmission rates.

WJM receives royalties from Zimmer Inc (Warsaw, IN) and Wright Medical Technology, Inc (Arlington, TN). JIH receives research support from Biomet Inc (Warsaw, IN) and is a consultant to Zimmer Inc (Warsaw, IN), Biomet, Smith and Nephew Inc (Memphis, TN), and PorOsteon Inc (Menlo Park, CA). All other authors certify that they have no commercial associations that might pose a conflict of interest in connection with the submitted article.
These data were generated by the US Department of Health and Human Services and thus review by our local institutional review board is not required.
Work performed at Qualidigm and Stanford University.