A total of 31,044 patients who underwent TKA and 19,909 patients who underwent THA were included in this study. Patients who underwent THA were more likely to be discharged early (postoperative length of stay of 0 to 2 days) compared with those who underwent TKA (THA, 31.4% of the patients; TKA, 20.8% of the patients) (Table I).
Baseline characteristics differed significantly between the early and standard discharge groups (Table II). Overall, patients who were discharged early were younger and had fewer medical comorbidities and a lower American Society of Anesthesiologists (ASA) score. Male patients were more likely than female patients to be discharged early following THA (42.6% compared with 27.2%; p < 0.0001) and following TKA (29.3% compared with 18.7%; p < 0.0001). Operative characteristics differed significantly between the early and standard discharge groups (Table II). Patients with a standard length of stay following either THA or TKA had an approximately 2.5-fold increase in the rate of transfusion compared with patients with an early discharge (p < 0.0001). Lastly, patients discharged early were significantly more likely to have been discharged to home compared with patients with a standard hospital admission: 91.3% of the patients in the early discharge group were discharged to home compared with 64.7% of the patients in the standard discharge group following THA (p < 0.0001). Patients who underwent TKA also showed a similar disposition, with 88.1% of the patients in the early discharge group going home compared with 63.6% of the patients in the standard discharge group (p < 0.0001).
The multivariable logistic-regression model revealed that early discharge was not associated with increased odds of major complications following TKA (odds ratio [OR] = 0.95; 95% confidence interval [CI] = 0.75 to 1.2; p = 0.64) (Table IV). Furthermore, early discharge following THA was found to be an independent predictor against major complications when controlling for all other risk factors (OR = 0.75; 95% CI = 0.58 to 0.95; p = 0.02). The logistic-regression analysis for 30-day readmission showed that early discharge was not an independent risk factor for hospital readmission following either primary THA (OR = 0.83; 95% CI = 0.67 to 1.01; p = 0.068) or TKA (OR = 0.86; 95% CI = 0.72 to 1.02; p = 0.088) (Table V).
Early discharge following total hip or knee replacement has been a recent topic of debate because of the increasing number of arthroplasties performed annually and the large economic burden such procedures place on the U.S. health-care system. However, shorter hospital admissions have raised concerns over possible increases in complication and readmission rates. We sought to determine whether early discharge, from 0 to 2 days, was associated with increased 30-day major complications and readmissions compared with standard discharge, from 3 to 4 days. The results of this study confirmed our hypothesis that early discharge is not an independent risk factor for either major complications or readmission following THA or TKA.
Appropriate candidates for early discharge should be carefully selected to avoid compromising patient safety. Our results revealed that patients discharged early were younger and healthier, received fewer transfusions, and were more likely to have been discharged to home. These findings are similar to those for Medicare beneficiaries following TKA that showed that patients undergoing an outpatient procedure or having a shortened hospital stay (1 to 2 days) were younger and had a lower Charlson comorbidity score compared with the 3 to 4-day standard-stay group21. Independent risk factors for major complications in our study differed slightly between hip and knee arthroplasty, and were the result of patient comorbidities and operative variables rather than length of hospital admission (Table IV). Major complications following THA were associated with discharge at 3 to 4 days, male sex, higher body mass index (BMI), corticosteroid use, a longer surgical duration, and postoperative transfusions. Independent predictors of a major complication after TKA included male sex, current-smoker status, an elevated BUN (blood urea nitrogen) value, a longer surgical duration, and discharge to a rehabilitation facility. Studies have shown that most complications following total joint arthroplasty occur beyond 24 hours postoperatively26,27. The authors of those studies recommended that patients with elevated BMI, a high ASA score, older age, or a history of chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), coronary artery disease (CAD), or cirrhosis not be discharged early given that these risk factors were all found to be independent predictors of a late complication26,27.
Readmissions following total joint arthroplasty are common and costly. The average cost of readmission following a surgical complication has been estimated to be $36,038 for THA and $32,922 for TKA28. The rates of all-cause 30-day readmission have further increased over the past 2 decades, from 4.2% to 5.0% after primary TKA and from 5.9% to 8.5% following THA18,19. The most common causes for readmission include surgical complications such as wound-related issues, bleeding, periprosthetic fractures and dislocations, and pain28,29. Common medical causes for readmission include gastrointestinal, pulmonary, and genitourinary issues, thromboembolic events, and systemic and cardiac-associated issues28,29.
In recent studies, Cram et al. reported that the decreasing trend in hospital length of stay is responsible for the rise in readmission following THA and TKA18,19. They suggested a limit in cost savings that can be achieved by further reducing the length of stay given the increased demand for postacute care and a higher rate of readmission. Although the authors inferred a causal relationship between the observed decrease in hospital length of stay and the increase in readmission rates, this was not directly measured. These studies further failed to control for patient factors and operative variables, and the findings conflict with those of the current study as well as those previously published30. We have shown that early discharge is not an independent risk factor for readmission and that appropriately selected patients can be discharged from 0 to 2 days without concerns over increased readmission. The results of our study mirror those of other studies showing that increased readmission can be attributed to patient and perioperative factors such as general anesthesia, discharge disposition, increased length of stay, and blood transfusions30. In a separate study of Medicare patients, the 2-year costs associated with TKA were reduced by $1,967 per patient with a length of stay from 1 to 2 days compared with 3 to 4 days21.
The limitations of our study are those characteristic of the use of large administrative databases. The NSQIP does not collect several variables relevant to arthroplasty, such as hospital location, operative approach (anterior, posterior, or lateral), type of implant, or the use of cement or a tourniquet. Several outcomes are also not recorded in the NSQIP database, such as dislocation, periprosthetic fractures, functional outcome scores specific to arthroplasty, or any event occurring beyond 30 days postoperatively, such as deep-vein thrombosis. Hospital and surgeon volume are also not reported by the NSQIP. Both of these variables are potential confounders and have been shown to affect the rate of adverse outcomes31,32. Consequently, our findings should be interpreted within the context of the study design because we were unable to account for unmeasured confounders, such as volume, on the relationship between length of stay and major complications. Despite these shortcomings, the NSQIP database is one of the largest of its kind and includes an extensive registry of perioperative variables and complications. This database was chosen because of its features to best evaluate our objectives. Databases that include only Medicare beneficiaries will exclude patients <65 years of age, who account for 41% to 46% of all patients undergoing TKA and THA20,33. Other U.S. databases, such as the Centers for Medicare & Medicaid Services Limited Data Sets, will also underestimate the true rate of 30-day outcomes such as readmission because they are unable to accurately link outpatient complications once the patient has been discharged to home or readmitted to a different hospital34. The NSQIP is ideal for evaluating risk factors for readmission because the database will capture all readmissions, even those occurring at a hospital other than where the index procedure was performed. The NSQIP is thoroughly audited and adheres to strict quality-control standards, making the database very useful for this type of study.
Length of stay following THA and TKA has been steadily decreasing over the past decade, and studies have shown excellent satisfaction and low complications with “fast-track” protocols35. The results of our study involving the use of a large administrative database showed that discharge within the first 2 postoperative days for risk-stratified patients appears to be safe, without increased risk of 30-day postoperative complications or hospital readmission. Lastly, patient comorbidities and operative variables are more predictive of major complications and readmission than shorter length of stay following THA and TKA.
Investigation performed at the Department of Orthopaedic Surgery, Jewish General Hospital, Montreal, Quebec, Canada
2. Centers for Disease Control and Prevention. Table 116: cost of hospital discharges with common hospital operating room procedures in nonfederal community hospitals, by age and selected principal procedure: United States, selected years 2000-2011. http://www.cdc.gov/nchs/data/hus/2013/116.pdf
. Accessed 2015 Jun 20.
3. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007 ;89(4):780–5. Epub 2007 Apr 4.
4. Mont MA, Issa K. Updated projections of total joint arthroplasty demands in America. Commentary on an article by Steven M. Kurtz, PhD, et al.: “Impact of the economic downturn on total joint replacement demand in the United States. Updated projections to 2021”. J Bone Joint Surg Am. 2014 ;96(8):e68. Epub 2014 Apr 18.
7. Peters CL, Shirley B, Erickson J. The effect of a new multimodal perioperative anesthetic regimen on postoperative pain, side effects, rehabilitation, and length of hospital stay after total joint arthroplasty. J Arthroplasty. 2006 ;21(6)(Suppl 2):132–8.
8. Kim S, Losina E, Solomon DH, Wright J, Katz JN. Effectiveness of clinical pathways for total knee and total hip arthroplasty: literature review. J Arthroplasty. 2003 ;18(1):69–74. Epub 2003 Jan 30.
9. Tayrose G, Newman D, Slover J, Jaffe F, Hunter T, Bosco J 3rd. Rapid mobilization decreases length-of-stay in joint replacement patients. Bull Hosp Jt Dis (2013). 2013;71(3):222–6.
10. Berger RA, Sanders S, Gerlinger T, Della Valle C, Jacobs JJ, Rosenberg AG. Outpatient total knee arthroplasty with a minimally invasive technique. J Arthroplasty. 2005 ;20(7)(Suppl 3):33–8. Epub 2005 Oct 11.
11. Dorr LD, Thomas DJ, Zhu J, Dastane M, Chao L, Long WT. Outpatient total hip arthroplasty. J Arthroplasty. 2010 ;25(4):501–6. Epub 2009 Jul 28.
12. Berger RA, Sanders SA, Thill ES, Sporer SM, Della Valle C. Newer anesthesia and rehabilitation protocols enable outpatient hip replacement in selected patients. Clin Orthop Relat Res. 2009 ;467(6):1424–30. Epub 2009 Feb 28.
14. Khuri SF, Daley J, Henderson W, Hur K, Demakis J, Aust JB, Chong V, Fabri PJ, Gibbs JO, Grover F, Hammermeister K, Irvin G 3rd, McDonald G, Passaro E Jr, Phillips L, Scamman F, Spencer J, Stremple JF; National VA Surgical Quality Improvement Program. The Department of Veterans Affairs’ NSQIP: the first national, validated, outcome-based, risk-adjusted, and peer-controlled program for the measurement and enhancement of the quality of surgical care. Ann Surg. 1998 ;228(4):491–507. Epub 1998 Oct 28.
17. Shiloach M, Frencher SK Jr, Steeger JE, Rowell KS, Bartzokis K, Tomeh MG, Richards KE, Ko CY, Hall BL. Toward robust information: data quality and inter-rater reliability in the American College of Surgeons National Surgical Quality Improvement Program. J Am Coll Surg. 2010 ;210(1):6–16. Epub 2009 Nov 22.
18. Cram P, Lu X, Kaboli PJ, Vaughan-Sarrazin MS, Cai X, Wolf BR, Li Y. Clinical characteristics and outcomes of Medicare patients undergoing total hip arthroplasty, 1991-2008. JAMA. 2011 ;305(15):1560–7. Epub 2011 Apr 21.
19. Cram P, Lu X, Kates SL, Singh JA, Li Y, Wolf BR. Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991-2010. JAMA. 2012 ;308(12):1227–36. Epub 2012 Sep 27.
20. Centers for Disease Control and Prevention; Wolford ML, Palso K, Bercovitz A. Hospitalization for total hip replacement among inpatients aged 45 and over: United States, 2000-2010. 2015 Feb. http://www.cdc.gov/nchs/products/databriefs/db186.htm
. Accessed 2016 Apr 8.
21. Lovald ST, Ong KL, Malkani AL, Lau EC, Schmier JK, Kurtz SM, Manley MT. Complications, mortality, and costs for outpatient and short-stay total knee arthroplasty patients in comparison to standard-stay patients. J Arthroplasty. 2014 ;29(3):510–5. Epub 2013 Aug 21.
23. Liodakis E, Bergeron SG, Zukor DJ, Huk OL, Epure LM, Antoniou J. Perioperative complications and length of stay after revision total hip and knee arthroplasties: an analysis of the NSQIP database. J Arthroplasty. 2015 May 22 Nov;30(11):1868-71. Epub 2015 May 22.
24. Hart A, Bergeron SG, Epure L, Huk O, Zukor D, Antoniou J. Comparison of US and Canadian perioperative outcomes and hospital efficiency after total hip and knee arthroplasty. JAMA Surg. 2015 ;150(10):990–8.
25. Hart A, Antoniou J, Brin YS, Huk OL, Zukor DJ, Bergeron SG. Simultaneous bilateral versus unilateral total knee arthroplasty: a comparison of 30-day readmission rates and major complications. J Arthroplasty. 2016 ;31(1):31–5. Epub 2015 Jul 21.
26. Courtney PM, Rozell JC, Melnic CM, Lee GC. Who should not undergo short stay hip and knee arthroplasty? Risk factors associated with major medical complications following primary total joint arthroplasty. J Arthroplasty. 2015 May 27 Sep;30(9)(Suppl):1-4. Epub 2015 May 27.
27. Parvizi J, Mui A, Purtill JJ, Sharkey PF, Hozack WJ, Rothman RH. Total joint arthroplasty: when do fatal or near-fatal complications occur? J Bone Joint Surg Am. 2007 ;89(1):27–32. Epub 2007 Jan 4.
28. Clair AJ, Evangelista PJ, Lajam CM, Slover JD, Bosco JA III, Iorio R. Cost analysis of total joint arthroplasty readmissions in a bundled payment care initiative. Proceedings of the 24th Annual Meeting of the American Association of Hip and Knee Surgeons; 2014 Nov 6-9; Dallas, TX.
29. Pugely AJ, Callaghan JJ, Martin CT, Cram P, Gao Y. Incidence of and risk factors for 30-day readmission following elective primary total joint arthroplasty: analysis from the ACS-NSQIP. J Arthroplasty. 2013 ;28(9):1499–504. Epub 2013 Jul 26.
30. Mesko NW, Bachmann KR, Kovacevic D, LoGrasso ME, O’Rourke C, Froimson MI. Thirty-day readmission following total hip and knee arthroplasty - a preliminary single institution predictive model. J Arthroplasty. 2014 ;29(8):1532–8. Epub 2014 Mar 4.
31. Katz JN, Losina E, Barrett J, Phillips CB, Mahomed NN, Lew RA, Guadagnoli E, Harris WH, Poss R, Baron JA. Association between hospital and surgeon procedure volume and outcomes of total hip replacement in the United States Medicare population. J Bone Joint Surg Am. 2001 ;83(11):1622–9.
32. Katz JN, Barrett J, Mahomed NN, Baron JA, Wright RJ, Losina E. Association between hospital and surgeon procedure volume and the outcomes of total knee replacement. J Bone Joint Surg Am. 2004 ;86(9):1909–16.
33. Losina E, Thornhill TS, Rome BN, Wright J, Katz JN. The dramatic increase in total knee replacement utilization rates in the United States cannot be fully explained by growth in population size and the obesity epidemic. J Bone Joint Surg Am. 2012 ;94(3):201–7.
34. Clair AJ, Inneh IA, Iorio R, Berend KR, Della Valle CJ, Healy WL, Pelligrini VD. Can administrative data be used to analyze complications following total joint arthroplasty? J Arthroplasty. 2015 ;30(9)(Suppl):17–20. Epub 2015 Jun 3.
35. Winther SB, Foss OA, Wik TS, Davis SP, Engdal M, Jessen V, Husby OS. 1-year follow-up of 920 hip and knee arthroplasty patients after implementing fast-track. Acta Orthop. 2015 ;86(1):78–85. Epub 2014 Sep 1.