The first THA procedures kept patients hospitalized for over 3 months.  The average hospital stay after THA has been getting shorter over the past few decades.  Medicare currently recognizes 3 day inpatient stay as the standard of care.  Yet this number is not set in stone, and patient stay continues to shorten as postoperative management continues to improve.

When deciding how long a patient must be hospitalized, we must first ask what is the integral function of the hospital.  Historically hospitalization was required to monitor blood loss, control pain, facilitate ambulation, and monitor for medical complications.  Advances in minimally invasive surgical technique, blood loss management, and patient optimization have reduced the need for blood transfusion.  Multimodal analgesia has improved postoperative pain control.  The combination of these protocols have improved early ambulation for patients. Compared to historical standards, blood loss, pain control, and ambulation are becoming less and less a reason for patients to require hospitalization. 

As a result the average length of stay has continued to decline.  A nationwide study from Denmark showed a 6 day drop in average length of stay after implementing protocols to address pain control and early mobilization [1].  Similar rapid recovery protocols implemented in the United States have effectively shortened hospital stay without increasing complications or emergency room readmissions[2].  Other studies have identified non-medical risk factors for prolonged hospitalization, further highlighting the notion that length of stay is rarely dictated by medical needs and more often due to culture[3].

The question then becomes: do all patients need to be hospitalized postop for monitoring of medical complications.  Courtney et al. examined 1,012 patients undergoing primary THA or TKA and found that 84% complications occurred within 24 hours postop and 90% occurring within 4 days.  The vast majority of complications occurred in patients with major comorbidities such as CHF, CAD, COPD, and liver failure. Older age was an additional risk factor [4].  In contrast however, a similar study that examined the timing of major postoperative complications found that over 90% occurred within the first 4 days of surgery yet almost 60% of cases occurred in patients without significant comorbidities [5].  Identifying at risk patients is clearing essential for determining length of stay.

Large national databases have been used recently to further identify risk factors for medical complications.

Age (>80), diabetes, BMI > 40, and ASA class (>3, indicator of comorbidities) were all associated with increased risk of 30 day morbidity and mortality after TKA [6].  Age and cardiac disease were associated with 30 day risk in THA [7].  Looking specifically at cardiac complications, hypertension and coronary artery disease comorbities as well as age > 80 were risk factors.[8]

These studies highlight the importance of preoperative screening to identify the risk factors that place a patient at risk for medical complications in the acute postoperative period and require hospital monitoring. However, it is apparent that serious medical complications can occur in any patient regardless of overall health. 

Does length of hospital stay affect the risk of complications? One study found no difference in complications in patients that were “short stay” (<3 days) vs. standard (3-4 days).  This study did however find a higher hospital readmission rate in older patients and those with more comorbidities (particular heart failure).  This suggests that patient factors, not length of hospital stay influenced the risk of a protracted recovery [9].  A similar study looked at early discharges and found no increased risk for readmission[10].

If the vast majority of medical complications are seen in patients with preoperative medical comorbidities, it is evident that these high-risk patients require hospitalization during the window when there is a higher incidence of acute complication.  But what about the patients without comorbities, those that are healthy except for debilitating osteoarthritis?  If they are at low risk for complications, and effective protocols are in place to control blood loss, pain, and to promote early mobilization…what do they need the hospital for? 

The historic dogma that all TJA patients require postoperative hospitalization has become questioned in the past decade. Even though the number of patients with comorbidities is increasing, the number of complications following TKA and THA is decreasing [11] [12].  Furthermore, if surgeons are able to successfully identify at risk patients, those that fall outside this cohort may be predisposing themselves to actual increased risk of hospital acquired infection by unnecessarily staying in the hospital. 

Several studies have demonstrated that TJA performed as same-day surgery is safe, effective and efficient in the properly selected patient.  These studies found no significant difference in morbidity or functional recovery. [13] [14] [15] [16].  These studies found that nausea was a common cause of delayed discharge, yet < 5% required hospital admission and < 1 % were seen in the emergency room if discharged. 

Unplanned readmissions are one of the measures to suggest that patients were discharged from the hospital too early.  Whether these issues would have been addressed in a standard hospital stay is debatable, as about 10% of complications occur after the standard 3-4 days hospitalization [17].  The overall readmission rate is about 5% within 90 days, with infection and stiffness being the most common cause for TKA. Risk factors for readmission included discharge to a rehab facility and longer (not shorter) hospital stay [18].  In THA population, cardiac issues were the most common cause in the Medicare population, but were unrelated to length of stay [19].  Risk factors for 30 day readmission included discharge to rehab, general anesthesia, Charleson Comorbidity index >2, and longer stay [20].  Difficulty coping with postoperative situation was not a major cause for readmission (5% of readmissions, 0.1% of all patients)[21].


1.         Husted, H., et al., Reduced length of stay following hip and knee arthroplasty in Denmark 2000-2009: from research to implementation. Arch Orthop Trauma Surg, 2012. 132(1): p. 101-4.

2.         Stambough, J.B., et al., Rapid recovery protocols for primary total hip arthroplasty can safely reduce length of stay without increasing readmissions. J Arthroplasty, 2015. 30(4): p. 521-6.

3.         Inneh, I.A., The Combined Influence of Sociodemographic, Preoperative Comorbid and Intraoperative Factors on Longer Length of Stay After Elective Primary Total Knee Arthroplasty. J Arthroplasty, 2015. 30(11): p. 1883-6.

4.         Courtney, P.M., et al., 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. 30(9 Suppl): p. 1-4.

5.         Parvizi, J., et al., Total joint arthroplasty: When do fatal or near-fatal complications occur? J Bone Joint Surg Am, 2007. 89(1): p. 27-32.

6.         Belmont, P.J., Jr., et al., Thirty-day postoperative complications and mortality following total knee arthroplasty: incidence and risk factors among a national sample of 15,321 patients. J Bone Joint Surg Am, 2014. 96(1): p. 20-6.

7.         Belmont, P.J., Jr., et al., Morbidity and mortality in the thirty-day period following total hip arthroplasty: risk factors and incidence. J Arthroplasty, 2014. 29(10): p. 2025-30.

8.         Belmont, P.J., Jr., et al., Postoperative myocardial infarction and cardiac arrest following primary total knee and hip arthroplasty: rates, risk factors, and time of occurrence. J Bone Joint Surg Am, 2014. 96(24): p. 2025-31.

9.         Lovald, S.T., et al., Complications, mortality, and costs for outpatient and short-stay total knee arthroplasty patients in comparison to standard-stay patients. J Arthroplasty, 2014. 29(3): p. 510-5.

10.       Vorhies, J.S., et al., Decreased length of stay after TKA is not associated with increased readmission rates in a national Medicare sample. Clin Orthop Relat Res, 2012. 470(1): p. 166-71.

11.       Memtsoudis, S.G., et al., Trends in demographics, comorbidity profiles, in-hospital complications and mortality associated with primary knee arthroplasty. J Arthroplasty, 2009. 24(4): p. 518-27.

12.       Liu, S.S., et al., Trends in mortality, complications, and demographics for primary hip arthroplasty in the United States. Int Orthop, 2009. 33(3): p. 643-51.

13.       Berger, R.A., et al., Minimally invasive quadriceps-sparing TKA: results of a comprehensive pathway for outpatient TKA. J Knee Surg, 2006. 19(2): p. 145-8.

14.       Berger, R.A., et al., Rapid rehabilitation and recovery with minimally invasive total hip arthroplasty. Clin Orthop Relat Res, 2004(429): p. 239-47.

15.       Berger, R.A., et al., Outpatient total knee arthroplasty with a minimally invasive technique. J Arthroplasty, 2005. 20(7 Suppl 3): p. 33-8.

16.       Berger, R.A., et al., Newer anesthesia and rehabilitation protocols enable outpatient hip replacement in selected patients. Clin Orthop Relat Res, 2009. 467(6): p. 1424-30.

17.       Yu, S., et al., Preventing Hospital Readmissions and Limiting the Complications Associated With Total Joint Arthroplasty. J Am Acad Orthop Surg, 2015. 23(11): p. e60-71.

18.       Zmistowski, B., et al., Unplanned readmission after total joint arthroplasty: rates, reasons, and risk factors. J Bone Joint Surg Am, 2013. 95(20): p. 1869-76.

19.       Vorhies, J.S., et al., Readmission and length of stay after total hip arthroplasty in a national Medicare sample. J Arthroplasty, 2011. 26(6 Suppl): p. 119-23.

20.       Mesko, N.W., et al., Thirty-day readmission following total hip and knee arthroplasty - a preliminary single institution predictive model. J Arthroplasty, 2014. 29(8): p. 1532-8.

21.       Avram, V., et al., Total joint arthroplasty readmission rates and reasons for 30-day hospital readmission. J Arthroplasty, 2014. 29(3): p. 465-8.

22.       Jencks, S.F., M.V. Williams, and E.A. Coleman, Rehospitalizations among patients in the Medicare fee-for-service program. N Engl J Med, 2009. 360(14): p. 1418-28.

23.       Mednick, R.E., et al., Factors Affecting Readmission Rates Following Primary Total Hip Arthroplasty. J Bone Joint Surg Am, 2014. 96(14): p. 1201-1209.