# Predicting Day-Case Arthroplasty Outcomes ## Which patient factors best predict success/failure of day-case arthroplasty? ### Increased age, female sex (OR 1.63-4.22), high ASA classification, and multiple comorbidities (OR up to 3.9) are the primary predictors of day-case arthroplasty failure. ## Abstract Day‐case arthroplasty outcomes are influenced by clear patient factors. Studies report that increased age—which in over 20 analyses shows odds ratios from 1.01 to 4.16—and female sex—with odds ratios from 1.63 to 4.22 in more than 15 investigations—predict lower same‐day discharge success. A higher body mass index (supported in 10+ studies) and non‐white race (noted in 5+ studies) similarly relate to reduced success. In addition, clinical indicators such as an ASA classification of III or IV and a comorbidity burden of three or more conditions consistently predict failure, with odds ratios up to 3.9 and highly significant p‐values. Other conditions, including hypertension, diabetes, cardiovascular disease, and chronic obstructive pulmonary disease, are also cited as contributing to poor day‐case outcomes. Although a couple of studies flag younger age (<40) as a potential risk factor, this finding remains inconsistent. ## Methods We analyzed 40 sources from an initial pool of 500, using 8 screening criteria. Each paper was reviewed for 6 key aspects that mattered most to the research question. ## Paper search Using your research question “Which patient factors best predict success/failure of day-case arthroplasty?”, we [searched](https://support.elicit.com/en/articles/553025) across over 126 million academic papers from the [Semantic Scholar](https://www.semanticscholar.org/) corpus. We retrieved the 500 papers most relevant to the query. ## Screening We screened in sources based on their abstracts that met these criteria: - **Study Setting**: Outpatient/day-case/ambulatory arthroplasty procedures. - **Patient Population - Age**: Adult patients (≥18 years). - **Procedure Type**: Primary (non-revision) hip, knee, shoulder, or ankle arthroplasty. - **Clinical Context**: Planned elective procedures (not emergency or trauma-related). - **Predictive Factors**: Patient-related predictive factors (age, BMI, comorbidities, social support). - **Outcome Measures**: Specific outcomes related to success/failure (same-day discharge, unplanned overnight stays, or 30-day readmissions). - **Study Design**: Prospective/retrospective cohort study, case-control, RCT, or systematic review with 10 or more patients. - **Study Focus**: Patient-related factors (not exclusively surgical technique, anesthetic protocol, hospital/surgeon factors). We considered all screening questions together for holistic judgment. ## Data extraction We asked a large language model to extract each data column below from each paper: - **Study Design**: - **Patient Selection Criteria**: - **Patient Demographic and Clinical Factors**: - **Reasons for Same-Day Discharge Failure**: - **Predictive Factors for Same-Day Discharge Success**: - **Surgical Procedure Details**: ## Results ### Characteristics of Included Studies | Study | Study Design | Sample Size | Setting Type | Primary Outcome Definition | Full text retrieved | |--------------------------------|-----------------------------------|-------------|--------------------|---------------------------------------------------------|---------------------| | Velichala et al., 2024 | Retrospective | 31,347 | No mention found | 30-day readmission after outpatient Total Knee Arthroplasty (TKA) | No | | Murrell et al., 2023 | Retrospective, single-center | 606 | Single-center | 24-hour discharge after elective hip/knee arthroplasty | Yes | |... | Danielsen et al., 2024 | Prospective, multicentre cohort | 6,142 | Multicenter | Day-case success after Total Hip Arthroplasty (THA), TKA, Medial Unicompartmental Knee Arthroplasty (mUKA)| Yes | ## Patient Demographics | Factor | Effect Size Range | Direction of Effect | Number of Supporting Studies | |-----------------|---------------------------------|---------------------------------------|-----------------------| | Age (older) | Odds Ratio (OR) 1.01–4.16 | Decreases same-day discharge success | 20+ | | Female sex | OR 1.63–4.22 | Decreases same-day discharge success | 15+ | |...| | Younger age (<40)| Increased risk in some studies | Decreases same-day discharge success (inconsistently)| 2 | ### Common Failure Patterns | Study | Most Common Reasons for Failure | Frequency/Proportion | |--------------------|-------------------------------------|--------------------------------| | Danielsen et al., 2024 | Mobilization issues, postoperative nausea and vomiting (PONV) | 9–14% by reason | |...| | Bayoumi et al., 2022| Inability to mobilize, pain, nausea/vomiting | 34%, 8%, 11% | ### Risk Stratification Models | Study | Model/Tool | Predictive Value | Notes | |----------------------|---------------------------------------------|---------------------------------|-------------------------------| | Meneghini et al., 2017 | Outpatient Arthroplasty Risk Assessment (OARA) score | OR 2.0–2.7 for early discharge | More predictive than ASA/CCI | |...| ## References 1. James Murrell, N. Khadabadi, Thomas Moores, Fahad Hossain. (2023). Identifying Preoperative Predictors for 24-Hour Discharge After Elective Hip and Knee Arthroplasties. Cureus 2. M. Keulen et al. (2020). Predictors of (Un)successful Same-Day Discharge in Selected Patients Following Outpatient Hip and Knee Arthroplasty. Journal of Arthroplasty 3. Ehab M. Nazzal, Fritz Steuer, Matthew Como, Ryan Gilbert, S. Adida. (2025). Predictors of Failing Same-Day Discharge after Shoulder Arthroplasty: Developing a Model to Improve Outcomes and Reduce Healthcare Cost. Journal of shoulder and elbow surgery ... (Additional references omitted for brevity.)