The authors present a unique twist on a very common and hot topic in the orthopedic literature.

Strengths of the paper:

The authors appropriately articulate the subject selection process via the ACS/NSQIP database utilizing CPT codes to identify elective THA and TKA patients. The authors have appropriately excluded bilateral cases, revision surgery, and concomitant procedures given the well-documented confounding effects these variables have on the outcome of interest (i.e. Discharge to Facility and NOT discharge home).

Weaknesses -

1- THA and TKA populations were not homogenous in that the THA cohort included fracture cases in the THA cohort. The authors should consider including these patients in the exclusion pool to limit the confounding element of trauma on discharge disposition.

2- There are several clinical variables that, if included in this study, would strengthen the potential clinical utility of this discharge risk calculator. Social demographics, BMI, and length of stay would have helped strengthen the overall results.

Major points

1. Large database review (NSQIP)
2. Appropriate statistical analyses and tests chosen given the variables in consideration

Minor points

1. This study does not add much to the current body of literature on elective TJA discharge disposition. I would invite feedback from the authors on the realistic clinical relevance having such a discharge calculator would have altering the overall clinical care pathways in the TJA bundled payment modles

Data and Results

Strengths

I like the authors' style for statistical analyses in this manuscript. Very appropriate. The results are reported clearly with statistical significance emphasized

Weaknesses

The authors fail to mention that the increase in 30-day mortality in Home vs Facility discharge is only in the univariate analyses. Thus, this result is subject to massive confounding from the other variables that will influence an overall poorer outcome (i.e. older patients get discharged to a facility as opposed to home ; Higher ASA score likewise).

Glaring weaknesses in terms of variables NOT included are BMI, specific medical comorbidity inclusion (Diabetes, CHF, COPD especially), and length of stay.

Major points

1. Excellent timely topic, relevant

Minor points

1. Little contributed to what we already did not know 2.