Skip to main content

Table 1 Demographic features of 1112 patients who underwent total knee arthroplasty surgery

From: Perioperative predictors of prolonged length of hospital stay following total knee arthroplasty: a retrospective study from a single center in China

VariablesSample, N (%)Mean ± SDMean LOS (days)P-value
Age (years) 67.9 ± 7.9 0.036
 ≤ 65396 (35.7) 7.9 ± 2.4 
 >65714 (64.3) 9.5 ± 3.6 
Gender   0.441
 Female927 (83.5) 8.3 ± 4.3 
 Male183 (16.5) 8.0 ± 4.2 
Clinical protocol   < 0.01
 Traditional protocol71 (6.4) 11.6 ± 2.3 
 Current protocol294 (26.5) 7.2 ± 1.9 
Operative time(min) 89.3 ± 21.5 < 0.01
 ≤ 70253 (22.8) 7.4 ± 4.0 
 70–110646 (58.3) 8.2 ± 4.3 
 ≥ 110210 (18.9) 9.5 ± 4.2 
Surgeon   < 0.01
 1297 (26.8) 7.9 ± 4.5 
 2320 (28.9) 8.57 ± 4.1 
 3306 (27.6) 7.4 ± 4.0 
 4186 (16.8) 10.2 ± 3.7 
ROM 91.3 ± 18.0 < 0.01
 <90°344 (35.4) 8.6 ± 4.4 
 ≥ 90°583 (64.6) 7.7 ± 4.1 
Complications   < 0.01
 Yes220 (19.8) 11.0 ± 4.2 
 No892 (80.2) 7.6 ± 4.0 
Intraoperative blood loss(ml) 219.8 ± 120.5 < 0.01
 ≤ 150291 (41.3) 7.7 ± 4.0 
 150–300287 (40.8) 8.2 ± 4.2 
 ≥ 300126 (17.9) 10.6 ± 4.0 
Preoperative Hb(g/L) 127.9 ± 13.7 0.571
 ≤ 110108 (9.7) 7.6 ± 4.4 
 110–140786 (70.8) 8.5 ± 4.3 
 ≥ 140116 (10.5) 7.3 ± 4.1 
BI Score   0.512
 ≤ 90576 (67.6) 7.3 ± 4.0 
 >90276 (32.4) 7.8 ± 4.2 
Day of operation   0.221
 Monday245 (22.0) 8.3 ± 4.4 
 Tuesday236 (21.2) 8.9 ± 4.1 
 Wednesday168 (15.1) 7.6 ± 3.9 
 Thursday212 (19.1) 8.4 ± 4.4 
 Friday210 (18.9) 8.1 ± 4.0 
Type of pay   0.412
 Selfpay577 (60.8) 8.0 ± 4.1 
 Medicare372 (39.2) 8.2 ± 4.4 
Ward   < 0.01
 A923 (83.2) 8.0 ± 4.2 
 B186 (16.8) 9.8 ± 4.1 
Transfusion   < 0.01
 Yes87 (7.8) 11.0 ± 5.2 
 No1025 (92.2) 8.1 ± 4.1 
ASA classification   0.015
 I/II920(82.7) 8.1 ± 3.5 
 III/IV192(17.3) 9.3 ± 4.1 
Comorbidities   0.043
 Healthy674 7.9 ± 4. 
 Cardiovascular85 8.5 ± 3.7 
 Neurological93 9.7 ± 3.2 
  1. P < 0.05 was considered statistically significant. ROM Range of motion, BI Barthel Index. SD Standard deviation, Hb Hemoglobin