Table 2 Univariate survival analysis of reoperation before PSM and after PSM

IBM

 < 25

107 (56.32)

24 (12.63)

0.61

44 (56.41)

14 (17.95)

0.17

 >  = 25

50 (26.32)

9 (4.74)

12 (15.38)

8 (10.26)

Sex

Male

80 (42.11)

16 (8.42)

0.80

32 (41.03)

10 (12.82)

0.35

Female

77 (40.53)

17 (8.95)

24 (30.77)

12 (15.38)

Smoking

No

149 (78.42)

32 (16.84)

0.61

54 (69.23)

22 (28.21)

0.37

Yes

8 (4.21)

1 (0.53)

2 (2.56)

0 (0)

Injuried side

Left

96 (50.53)

19 (10)

0.70

29 (37.18)

14 (17.95)

0.34

Right

61 (32.11)

14 (7.37)

27 (34.62)

8 (10.26)

Diabetes

No

132 (69.47)

29 (15.26)

0.58

45 (57.69)

18 (23.08)

0.88

Yes

25 (13.16)

4 (2.11)

11 (14.1)

4 (5.13)

Occupation

Non-heavy manual workers

123 (64.74)

23 (12.11)

0.28

46 (58.97)

16 (20.51)

0.35

Heavy manual workers

34 (17.89)

10 (5.26)

10 (12.82)

6 (7.69)

Interval between injury and surgery

 <  = 72 h

61 (32.11)

12 (6.32)

0.79

12 (15.38)

8 (10.26)

0.17

 > 72 h

96 (50.53)

21 (11.05)

44 (56.41)

14 (17.95)

Reduction type

Closed reduction

145 (76.32)

29 (15.26)

0.40

50 (64.1)

19 (24.36)

0.72

Open reduction

12 (6.32)

4 (2.11)

6 (7.69)

3 (3.85)

Reduction quality

Imperfect

30 (15.79)

20 (10.53)

 < 0.001

22 (28.21)

17 (21.79)

0.003

Perfect

127 (66.84)

13 (6.84)

34 (43.59)

5 (6.41)

Location of fracture line

Subcapital

54 (28.42)

22 (11.58)

0.002

20 (25.64)

15 (19.23)

0.018

Transcervical

85 (44.74)

10 (5.26)

28 (35.9)

7 (8.97)

Basicervical

18 (9.47)

1 (0.53)

8 (10.26)

0 (0)

Garden Classification

II

30 (15.79)

1 (0.53)

0.001

1 (1.28)

0 (0)

0.30

III

55 (28.95)

5 (2.63)

16 (20.51)

3 (3.85)

IV

72 (37.89)

27 (14.21)

39 (50)

19 (24.36)

Pauwels Classification

I

35 (18.42)

7 (3.68)

0.99

8 (10.26)

4 (5.13)

0.30

II

74 (38.95)

16 (8.42)

22 (28.21)

12 (15.38)

III

48 (25.26)

10 (5.26)

26 (33.33)

6 (7.69)

Age (years)(QSD)

53.1 (38.5,59)

57  (41,59.5)

0.011

50.5  (38,58.5)

56.5  (51.5,59.25)

0.068