Table 1.

Details of the studies

Study	Inclusion criteria	Number of patients	Demographics m/f (mean age) (BMI)	Number of complications-readmissions-deaths	Follow-up (months)
Arshi et al. [23] J Bone Joint Surg Am	Patients underwent TKA in PDPR database. Code CPT 27447	O: 4,391 I: 128,951 Total: 133,342	O: 1,560/2831 (na) (na) I: 46,805/82,146 (na) (na)	O: 833-na-na I: 18,049-na-na	12
Cassard et al. [24] Orthop Traumatol Surg Res	Consecutive patients undergone TKA in the institute	O: 61 I: 513 Total: 574	O: 38/23 (65.4) (na) I: 251/262 (70.5) (na)	O: 5-2-0 I: 37-25-0	1
Darrith et al. [25] J.Arthroplasty	No specific BMI or age cutoff, in general patients were physiologically young, without medical comorbidities that required an inpatient admission	O: 46 I: 46 Total: 92	O: na (na) (na) I: na (na) (na)	O: 5-0-0 I: 5-0-0	3
Gauthier-Kwan et al. [26] J.Arthroplasty	patients undergone primary TKA for end-stage osteoarthritis an ASA of 3 or less with a stable medical profile, and a BMI under 45 kg/m2	O:43 I:43 tot:86	O:29/14 (62.5)(28.6) I:22/21 (62.5)(30.4)	O:8-1-na I:6-1-na	3
Gillis et al. [27] Int Orthop	Consecutive patients undergone TKA in the institute	O: 125 I: 275 Total: 400	O: 58/64 (62.9) (33.5) I: 107/168 (66) (28.8)	O: 17-3-0 I: 36-12-0	3
Kimball et al. [30] Orthopedics	18 years or older listed as outpatient or inpatient in their database	O: 863 I: 863 Total: 1726	O: 373/490 (na) (na) I: 373/490 (na) (na)	O: na-44-na I: na-63-na	3
Nowak et al. [28] Bone Joint J	18 years or older who underwent TKA between 2005 and 2016 using the ACS NSQIP database	O: 986 I: 75,260 Total: 76,246	O: 328/658 (67.5) (32) I: 27,105/48,155 (67.1) (31.8)	O: 44-na-na I: 2331-na-na	1
Springer et al. [29] Orthop Clin North Am	Healthy patients with no active cardiopulmonary conditions, no history of sleep apnea, deep venous thrombosis, or pulmonary embolus, BMI) less than 40, good family support at home	O: 92 I: 74 Total: 166	O: na (na) (na) I: na (na) (na)	O: 15-12-na I: 7-6-na	1