Same-day joint replacement is offered to selected patients, and the selection is the point.

Outpatient joint replacement means going home the same day

After a hip or knee replacement, patients typically either stay one night in the hospital or go home on the day of surgery. The second pathway is called outpatient, or same-day, joint replacement ¹. What changes is where the first night is spent, and the preparation that makes that possible.

Before a same-day discharge, patients are expected to have fully recovered from anesthesia ¹. They also need a friend or family member who can drive them to therapy and follow-up appointments ¹. Programs build in preparation at home ahead of time: one-level living where possible, physical therapy scheduled in advance, walking aids obtained, and meals arranged ¹.

Medical health is the first criterion

Surgeon societies describe the typical candidate as a healthy, active person with no major or ongoing medical problems ². Conditions treated as reasons for an overnight stay include heart disease, congestive heart failure, poorly controlled diabetes, chronic lung disease, chronic kidney disease, and sleep apnea ². AAOS patient guidance lists severe heart failure, COPD, obstructive sleep apnea, kidney failure, and dialysis as conditions that call for close monitoring after surgery ¹.

A published review of the outpatient literature reached a similar list. Candidates were patients willing to participate, with a low anesthesia risk class, having a first-time replacement, under 75, and with support at home in the first days ³. Exclusions reported in studies included bleeding disorders, poorly controlled heart or lung disease, uncontrolled diabetes, and chronic opioid use ³. They also included dependent functional status, kidney disease, reduced cognitive capacity, and a body mass index above 30 ³.

Sources disagree on weight. That review names a BMI cutoff; the surgeon-society patient pages do not ²³. Your surgeon decides how these factors apply from your exam, imaging, and history.

Some programs use a formal risk score

One widely cited tool is the Outpatient Arthroplasty Risk Assessment, or OARA, score. An arthroplasty surgeon and a perioperative internal medicine specialist developed it to sort patients into a lower-risk group and a not-appropriate group for early discharge ⁴. In the original series of 1,120 replacements, patients with a lower score were about twice as likely to go home the same or next day ⁴. The score predicted early discharge better than the general anesthesia risk class ⁴.

The authors noted that the score worked better alongside a deliberate patient-education pathway, and advised considering a program's maturity before adopting it ⁴. A score is a screening aid. It does not replace the surgical team's judgment.

Home support and anesthesia are part of the decision

The AAHKS position statement, updated in 2024, frames outpatient discharge as a shared decision between surgeon and patient after a comprehensive risk and benefit discussion ⁵. It asks programs to weigh three things ⁵. The first is medical comorbidity and the need for close monitoring. The second is social factors such as home support and physical barriers at home. The third is surgical complexity, including longer operative times or additional instrumentation ⁵.

Patient-education pages from the same society are direct on one point: patients who live alone with no one to care for them at home are not candidates ². Balance problems, or a chronic neurologic disease that limited walking before surgery, are also listed as reasons for an inpatient stay ².

The safety evidence is reassuring for selected patients, with caveats

A 2019 systematic review pooled seven studies covering 176,179 inpatient and 1,613 outpatient replacements ⁶. It found no significant difference in total complications, major complications, readmissions, deep vein thrombosis, or wound complications ⁶. Reoperations were more frequent in the outpatient group, and the authors concluded that careful preoperative selection is required ⁶.

Not every analysis agrees. A 2020 meta-analysis of eight knee-replacement studies reported a higher overall complication rate for outpatients, 16.1% against 10.5%, with no difference in readmissions ⁷. It graded the underlying evidence as very low quality ⁷. The AAHKS statement summarizes the literature as showing outpatient arthroplasty to be safe and effective with properly selected patients and a skilled surgeon ⁵. The safety record belongs to selected patients in prepared programs, not to same-day surgery in general.

If the plan changes on the day

A same-day plan is a plan, not a promise. In one series of 1,002 patients booked for same-calendar-day discharge, 59 (5.9%) stayed overnight instead ⁸. The most common reasons were difficulty mobilizing, nausea and vomiting, and social circumstances, and the median stay for that group was one night ⁸. The AAHKS statement notes that not all patients suit the outpatient setting, and that those patients must keep access to inpatient care ⁵.

Questions to ask your surgeon before the date is set:

• Which of my medical conditions would change the discharge plan?
• What does your program require at home, and who needs to be there?
• What happens if I am not ready to leave on the day, and where would I stay?
• Who do I call on the first night, and which warning signs need a call?