Single-Strand "Short Isometric Construct" Medial Collateral Ligament Reconstruction Restores Valgus and Rotational...

Area of Science:

• Orthopedic surgery
• Biomechanics
• Knee joint anatomy

Background:

• Historical medial collateral ligament reconstruction (MCLR) techniques often overlooked the deep MCL (dMCL)'s role in rotational stability.
• Recent research highlights the importance of the entire medial ligament complex, prompting a re-evaluation of current MCLR methods.

Purpose of the Study:

• To evaluate the effectiveness of isolated superficial MCL reconstruction (sMCLR), isolated dMCL reconstruction (dMCLR), and a novel single-strand short isometric construct reconstruction (SICR) in restoring knee stability.
• To compare the biomechanical outcomes of these different surgical approaches in a cadaveric model.

Main Methods:

• Biomechanical testing of 14 cadaveric knees using a multiaxial simulator.
• Specimens underwent testing in intact, injured (sMCL and dMCL transection), and reconstructed states.
• Four loading conditions (valgus torque, external rotation torque, anterior drawer, combined) were applied across a range of knee flexion angles.

Main Results:

• Both isolated sMCLR and dMCLR provided incomplete stability restoration across all flexion angles and loading conditions.
• Isolated dMCLR improved external rotation but not valgus stability, except at 0° flexion.
• Single-strand SICR successfully restored both valgus and external rotation stability throughout the entire range of knee motion.

Conclusions:

• Single-strand SICR is a promising technique for restoring comprehensive valgus and rotational stability in knees with combined sMCL and dMCL injuries.
• Neither isolated sMCLR nor isolated dMCLR alone can fully address the instability associated with combined medial collateral ligament injuries.