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Table 10 Association between individual potential prognostic factors and length of stay in overall cohort

From: Patient and surgical prognostic factors for inpatient functional recovery following THA and TKA: a prospective cohort study

Potential prognostic factors

rS or U, Z values

IQR LOS (nights) for groups

p value

Patient-related factors

  

 Gender (0 = female, 1 = male)

14685.0, − 1.022

IQR female (4.0–5.0), IQR male (4.0–5.0)

0.31

 Age

0.20

< 0.001**

 BMI

0.06

0.29

 ASA

0.12

0.03*

 Hb

− 0.03

0.54

 Living situation

0.04

0.51

 RAPT score

− 0.27

< 0.001**

 Pre-op pain (VAS)

0.08

0.15

 Pre-op patient-reported general health (EQ-5D VAS)

− 0.11

0.03*

 Pre-op patient-reported function (OKS/OHS)

− 0.18

0.001**

 Pre-op function (mILAS)

0.20

< 0.001**

 Pre-op function (TUG)

0.26

< 0.001**

 Pre-op function (10mWT)

0.21

< 0.001**

Surgical factors

  

 Arthroplasty site (0 = THA, 1 = TKA)

12065.0, − 1.996

IQR THA (3.0–5.0), IQR TKA (4.0–5.0)

0.05*

 Robot-assisted surgery (0 = no, 1 = yes)

5337.0, − 0.690

IQR no (4.0–5.0), IQR yes (3.25–5.0)

0.49

 GA only (0 = no, 1 = yes)

10172.5, − 2.769

IQR no (4.0–5.0), IQR yes (3.0–5.0)

0.006**

 GA and spinal anaesthesia (0 = no, 1 = yes)

13215.0, − 2.419

IQR no (3.0–5.0), IQR yes (4.0–5.0)

0.02*

 Sedation and spinal anaesthesia (0 = no, 1 = yes)

7972.0, − 0.373

IQR no (4.0–5.0), IQR yes (4.0–5.0)

0.71

 LIA use (0 = no, 1 = yes)

7150.0, − 2.398

IQR no (4.0–5.75), IQR yes (4.0–5.0)

0.02*

 PCA use (0 = no, 1 = yes)

9709.0, − 1.122

IQR no (4.0–5.0), IQR yes (4.0–6.0)

0.26

 Intra-articular catheter (TKA only) (0 = no, 1 = yes)

6671.0, − 0.755

IQR no (4.0–5.0), IQR yes (4.0–5.0)

0.45

 Single-shot regional block (TKA only) (0 = no, 1 = yes)

2566.5, − 1.867

IQR no (4.0–5.0), IQR yes (4.0–6.0)

0.06

 Ambulatory regional block (TKA only) (0 = no, 1 = yes)

2437.0, − 0.720

IQR no (4.0–5.0), IQR yes (3.0–5.5)

0.47

 Surgical approach (THA only) (0 = PA, 1 = DAA or DSA)

975.5, − 3.645

IQR PA (4.0–5.0), IQR DAA or DSA (3.0–4.0)

< 0.001**

 Surgery duration

− 0.03

0.52

 Tourniquet duration (TKA only)

− 0.02

0.94

 Tourniquet pressure (TKA only)

− 0.02

0.50

Post-operative factors

  

 DOS mobilisation (0 = no, 1 = yes)

10,659.0−2.443

IQR no (4.0–6.0), IQR yes (4.0–5.0)

0.02*

 Incidence of post-operative progress barriers (0 = no, 1 = yes)

8482.5, − 7.735

IQR no (3.0–4.0), IQR yes (4.0–6.0)

< 0.001**

 POD 2 mILAS

0.54

< 0.001**

 POD 2 TUG

0.31

< 0.001**

 POD 2 10mWT

0.28

< 0.001**

  1. p values were derived from Spearman’s correlation or Mann-Whitney U test, as appropriate for variable type
  2. ASA American Society of Anaesthesiologists, BMI body mass index, DAA direct anterior approach, DSA direct superior approach, DOS day of surgery, EQ-5D VAS EuroQol-5 Dimension Visual Analogue Scale, GA general anaesthesia, Hb haemaglobin, IQR inter-quartile range, LIA local infiltration analgesia, LOS length of stay, mILAS modified Iowa Level of Assistance Scale, OKS Oxford Knee Score, OHS Oxford Hip Score, PA posterior approach, PCA patient-controlled analgesia, POD post-operative day, RAPT Risk Assessment and Prediction Tool, THA total hip arthroplasty, TKA total knee arthroplasty, TUG Timed Up and Go test, VAS visual analogue scale, 10mWT ten-metre walk test
  3. *Statistical significance p < 0.05 level
  4. **Statistical significance p < 0.01 level
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Journal of Orthopaedic Surgery and Research

ISSN: 1749-799X