A new method to determine graft angles after knee ligament reconstruction

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Sports Medicine

Background:

• Graft failure in posterior cruciate ligament (PCL) reconstruction is a significant concern.
• The 'killer curve' at the tibial tunnel entrance is a suspected cause of PCL graft failure.
• Acute graft angles at the femoral tunnel entrance may also contribute to graft issues.

Purpose of the Study:

• To develop a method for accurately measuring the true graft angle in posterior cruciate ligament (PCL) reconstruction.
• To analyze the impact of tunnel positioning on graft angles.
• To investigate the biomechanical forces acting on the graft within the tunnels.

Main Methods:

• Utilized a cadaveric model for PCL reconstruction.
• Employed two orthogonal radiographs for data acquisition.
• Applied three-dimensional geometry for precise angle measurements.
• Analyzed the effects of knee flexion and extension on graft angles.

Main Results:

• Presented true tibial and femoral tunnel angles for various positions.
• Quantified the influence of knee joint movement on graft angles.
• Described graft-tunnel forces under constant ligament tension.

Conclusions:

• Outside-in femoral tunnel drilling is theoretically advantageous for PCL reconstruction.
• Lateral tibial tunnel placement is also theoretically beneficial.
• Optimizing tunnel angles may reduce PCL graft failure.