Table 2 Comparison of different outcome variables between the two portal groups

Portal distance from the patellar tendon (mm)

10.07 ± 0.95 (range: 8–12)

34.38 ± 3.54 (range: 28–42)

p < 0.05

Femoral tunnel length (mm)

42.43 ± 4.36 (range: 33–55)

31.51 ± 2.69 (range: 22–38)

p < 0.05

Femoral tunnel inclination (°)

44.06 ± 6.24 (range: 34–61)

38.43 ± 5.77 (range: 22.4–49)

p < 0.05

Tunnel exit zone

A: 12

B: 96

C: 9

A: 0

B: 38

C: 76

p < 0.05

Subgrouping of zone C tunnel exit

C1: 9

C2: 0

C3: 0

C1: 46

C2: 23

C3: 7

p < 0.05

Tunnel-related complications (n)

Nil

Lateral blowout: n = 2

MFC chondral injury: n = 10

Intraoperative button subsidence: n = 2

p < 0.05

Number (%) of patients with a short tunnel (< 28 mm)

None

6 (5%)

p < 0.05

Significant factors influencing tunnel length (regression coefficient)

BMI (−0.38)

BMI (−0.08)

p < 0.05 for specified factors

Significant factors influencing tunnel inclination (regression coefficient)

BMI (−0.43)

1. BMI (−0.24)

2. Graft diameter (1.45)

3. Portal medialization distance (−0.77)

p < 0.05 for specified factors