Table 3 Risk factors associated with reoperation in FNS

Age at surgery (years)

62.3 (57.7–67.0)

60.0 (54.9–64.1)

0.761

0.989

0.921–1.062

Sex

0.191

4.8

0.456–50.498

 Female

24 (61.5%)

1 (25%)

 Male

15 (38.5%)

3 (75%)

BMI (kg/m²)

22.6 (57.7–67.0)

23.0 (21.2–24.8)

0.799

1.047

0.737–1.488

Stroke history

2 (5.1%)

2 (50%)

0.018

18.5

1.642–84.62

Charlson comorbidity index

3.4 (2.6–4.3)

3.8 (2.7–4.8)

0.982

Garden classification

0.058

0.100

0.009–1.083

 Garden 1 & 2 (Stable)

30 (76.9%)

1 (25%)

 Garden 3 & 4 (Unstable)

9 (23.1%)

3 (75%)

Pauwels classifications

0.886

 Pauwels 1

8 (20.5%)

0

 Pauwels 2

22 (56.4%)

3 (75%)

 Pauwels 3

9 (23.1%)

1 (25%)

Tip-apex distance (mm)

19.4 (17.6–21.2)

38.1 (24.4–51.7)

0.016

1.244

1.041–1.0485

Cleveland index

0.444

0.444

0.056–3.538

 Ideal (zone 5, 8)

27 (69.2%)

2 (50%)

 Non-ideal (zone 4, 6, 7, 9)

12 (30.8%)

2 (50%)

Bolt sliding length (mm)

2.6 (1.7–3.4)

11.9 (9.4–14.3)

0.015

2.017

1.147–3.545