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Table 2 Results of comparison between same-stage and two-stage ‘young and fit’ subgroup (non-obese, non-complex, ASA 1 or 2, age < 75 years)

From: Cost, safety, and rehabilitation of same-stage, bilateral total knee replacements compared to two-stage total knee replacements

Subgroup analysis demographics Same-stage, bilateral TKR (n = 95) Two-stage, bilateral TKR ‘young and fit’ subgroup (n = 22) P
Gender and number 26 M, 69 F 6 M, 16 F 0.556
Age 65.6 (51–77, SD 5.31, 95% CI 64.5–66.7) 66.1 (56–74, SD 4.94, 95% CI 64–68.2) 0.415
ASA grade 1: 5, 5.26%, 1: 3, 13.64% 0.161
2: 90, 94.74% 2: 19, 86.36%  
3: 0, 0% 3: 0, 0%  
FS 50.3 (5–80, SD 12.99, 50.1 (5–90, SD 18.64, 0.083
95% CI 47.7–52.9) 95% CI 42.3–57.9)  
KS 44.3 (18–79, SD 13.54, 44.7 (12–74, SD 12.97, 0.412
95% CI 41.6–47) 95% CI 39.3–50.1)  
OKS 24.9 (8–54, SD 6.69, 25.3 (6–54, SD 8.41, 0.556
95% CI 23.5–26.3) 95% CI 21.5–28.5)  
ALOS (Days) 6.64 (3–12, SD 2.13, 11.29a (7–15, SD 1.55, <  0.001
95% CI 6.21–7.07) 95% CI 10.6–11.9)  
HbDrop (g/dL) 3.03 (0.0–6.0, SD 1.21, 2.20 ( 0.1–6.2, SD 1.02, <  0.001
95% CI 2.19–3.27) 95% CI 1.77–2.63)  
TV (units) for 2 knees 0.18 (0–6, SD 1.21, 0.10 (0–4, SD 1.02, 0.289
95% CI − 0.063–0.42) 95% CI − 0.36–0.53)  
Transfusion percentage 8.42% (16 of 190 knees) 9.09% (4 of 44 knees) 0.886
RR 3.16% (6 of 190 knees) 6.81% (3 of 44 knees) 0.255
Surg CR 3.68% (7 of 190 knees) 9.09% (4 in 44 knees) 0.127
Med CR 10.5% (10 of 95 operations) 4.55% (2 of 44 operations) 0.243
  1. Abbreviations: ALOS average length of stay, ASA American Society of Anesthesiologists, FS Knee Society Function Score, HbD1 haemoglobin level on first day post-operation, HbDrop haemoglobin level drop, KS Knee Society Knee Score, MedCR medical complication rate, OKS Oxford Knee Score, OccS occupational therapy sessions, OTT operation theatre time, PhyS physical therapy sessions, PreHb pre-operative haemoglobin, RR reoperation rate, SD standard deviation, SurgCR surgical complication rate, TV transfusion volume, UPR unplanned readmission, 95% CI 95% confidence interval
  2. Statistically significant P values are presented in bold
  3. apatient-specific total ALOS of 2 knees in an individual patient
  4. bknee-specific ALOS of one knee
  5. cpresented as the total operation time for both knees
  6. dpresented as the total number for both knees