Double-Bundle Medial Collateral Ligament Reconstruction Improves Anteromedial Rotatory Instability

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Knee Ligament Reconstruction

Background:

• Existing techniques for anteromedial rotatory instability in medial collateral ligament (MCL)-injured knees often require additional grafts and implants, limiting their clinical feasibility.
• Anteromedial rotatory instability is a significant concern in MCL injuries, impacting knee function and stability.

Purpose of the Study:

• To evaluate if a double-bundle (DB) MCL reconstruction with anterior proximal tibial fixation improves resistance to anteromedial rotatory instability compared to the standard single-bundle (SB) MCL reconstruction.
• To assess the biomechanical performance of different MCL reconstruction techniques in restoring knee kinematics.

Main Methods:

• A robotic simulator tested eight human cadaveric knees in intact, MCL-deficient, and reconstructed states.
• Kinematic data (valgus rotation, tibial rotation, anteromedial rotation/translation) were collected at multiple flexion angles under simulated loads.
• Three reconstruction types were compared: DB MCL without proximal tibial fixation, and DB and SB MCL with proximal tibial fixation.

Main Results:

• MCL deficiency significantly increased valgus rotation and anteromedial rotation/translation across most flexion angles.
• All tested reconstructions restored valgus rotation to intact levels, except at 90° flexion.
• The DB MCL reconstruction with anterior proximal tibial fixation demonstrated superior control of anteromedial rotation/translation compared to SB MCL reconstruction, particularly at or above 30° flexion.

Conclusions:

• A double-bundle MCL reconstruction with anteriorly placed proximal tibial fixation effectively controls anteromedial rotatory instability and anteromedial translation.
• This technique may be biomechanically superior to the standard single-bundle MCL reconstruction for managing anteromedial rotatory instability.
• The findings suggest a potentially more effective surgical option for MCL injuries without increasing surgical complexity or cost.