Table 1 Results of univariate and multivariate logistic regression analyses for classification of fracture age

Classification of fracture age (< 3 weeks vs ≥ 3 weeks)

 Results of univariate analysis

  Age

0.007

1.012

0.117

  Sex

0.170

0.667

0.017

  Ribs 1–4 fractures

0.077

2.630

 < 0.001

  Pleural inflammation

0.209

0.257

 < 0.001

  Lateral fractures

0.198

2.267

 < 0.001

  Bone fragments

0.372

0.512

0.072

  Multiple fractures of the same rib

0.160

1.582

0.004

  Cartilage junction fractures

0.077

2.630

 < 0.001

  Periosteal callus information

0.077

2.630

 < 0.001

  Intramedullary callus information

0.180

6.706

 < 0.001

 Positive results of multivariate logistic regression analysis

  Sex

0.234

2.189

0.001

  Ribs 1–4 fractures

0.199

2.060

 < 0.001

  Pleural inflammation

0.254

0.238

 < 0.001

  Lateral fractures

0.238

2.189

0.001

  Periosteal callus formation

0.222

5.236

 < 0.001

  Intramedullary callus formation

3.565

3.565

 < 0.001

Classification of fracture age (3–12 weeks vs > 12 weeks)

 Results of univariate analysis

  Age

0.009

1.010

0.274

  Sex

0.168

0.595

0.020

  Ribs 1–4 fractures

0.165

1.401

0.041

  Pleural inflammation

0.399

0.246

 < 0.001

  Lateral fractures

0.172

1.273

0.161

  Bone fragments

0.523

0.402

0.082

  Multiple fractures of the same rib

0.165

0.492

 < 0.001

  Cartilage junction fractures

0.250

1.025

0.920

  Periosteal callus formation

0.167

0.592

0.002

  Intramedullary callus information

0.270

0.258

 < 0.001

 Positive results of multivariate logistic regression analysis

  Pleural inflammation

0.419

0.244

0.001

  Multiple fractures of the same rib

0.175

0.528

 < 0.001

  Intramedullary callus formation

0.305

0.334

 < 0.001