# 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. 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.

## 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. More on methods.

## Papers identified with Elicit search
- n = 500
- Papers screened using: Study Setting, Patient Population - Age, Procedure Type, Clinical Context, Predictive Factors, Outcome Measures, Study Design, Study Focus
- n = 500 Papers screened out
- n = 460 Papers included for extraction
- n = 40

## 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**: Does the study investigate outpatient/day-case/ambulatory arthroplasty procedures?
- **Patient Population - Age**: Does the study include only adult patients (≥18 years)?
- **Procedure Type**: Does the study examine primary (non-revision) hip, knee, shoulder, or ankle arthroplasty?
- **Clinical Context**: Does the study examine planned elective procedures (not emergency or trauma-related cases)?
- **Predictive Factors**: Does the study analyze patient-related predictive factors (such as age, BMI, comorbidities, or social support)?
- **Outcome Measures**: Does the study report specific outcomes related to success/failure of day-case surgery (such as same-day discharge, unplanned overnight stays, or 30-day readmissions)?
- **Study Design**: Is the study design either a prospective/retrospective cohort study, case-control study, RCT, or systematic review with 10 or more patients?
- **Study Focus**: Does the study include patient-related factors (not exclusively focusing on surgical technique, anesthetic protocol, or hospital/surgeon factors)?

We considered all screening questions together and made a holistic judgment about whether to screen in each paper.

## Data extraction
We asked a large language model to extract each data column below from each paper. We gave the model the extraction instructions shown below for each column.

- **Study Design**:
Identify the type of study used:
  - Specify whether it is retrospective, prospective, or cross-sectional
  - Note if single-center or multi-center

- **Patient Selection Criteria**:
Extract the specific inclusion and exclusion criteria used for patient selection.

- **Patient Demographic and Clinical Factors**:
Extract key patient characteristics that could predict day-case arthroplasty success.

- **Reasons for Same-Day Discharge Failure**:
List all documented reasons for unsuccessful same-day discharge.

- **Predictive Factors for Same-Day Discharge Success**:
Extract statistical predictors of same-day discharge success.

- **Surgical Procedure Details**:
Extract specific details about surgical procedures.

# 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 | - | 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 |
| ... | ... | ... | ... | ... | ... |

## Patient Demographics
| Factor | Effect Size Range | Direction of Effect | Number of Supporting Studies |
|--------|------------------|--------------------|----------------------------|
| Age (older) | Odds Ratio (OR) 1.01–4.16, Relative Risk (RR) 1.44 | Decreases same-day discharge success | 20+ |
| Female sex | OR 1.63–4.22, RR 2.76 | Decreases same-day discharge success | 15+ |
| ... | ... | ... | ... |

## Common Failure Patterns
| Study | Most Common Reasons for Failure | Frequency/Proportion |
|-------|------------------------------|---------------------|
| Danielsen et al., 2024 | Mobilization issues, prolonged spinal anesthesia | 9–14% by reason |
| Gong et al., 2023 | Failure to clear Physical Therapy, hypotension | 33%, 20.5%, 16.9% |
| ... | ... | ... |

## 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/Charlson Comorbidity Index (CCI) |
| Crawford et al., 2022 | OARA score | Accurate for same-day discharge | May be too restrictive |
| ... | ... | ... | ... |

## References
- [James Murrell, N. Khadabadi, Thomas Moores, Fahad Hossain\(2023).Identifying Preoperative Predictors for 24-Hour Discharge After Elective Hip and Knee Arthroplasties. Cureus](/content/review/06cf70b4-de59-4ef1-aad8-59582b2cd184/source/d82a660ab8b94ba8bd4613ebc31aaf24/index.html)
- [M. Keulen, Sofie Asselberghs, B. Boonen, R. Hendrickx, E. V. van Haaren, and 1 more\(2020).Predictors of (Un)successful Same-Day Discharge in Selected Patients Following Outpatient Hip and Knee Arthroplasty. Journal of Arthroplasty](/content/review/06cf70b4-de59-4ef1-aad8-59582b2cd184/source/58d891fb91a44678a8a2c144c6ade049/index.html)
- ...