Lateral Extra-articular Tenodesis Provides Superior Stability in ACL Reconstruction With Posterolateral Tibial...

Area of Science:

• Orthopedic biomechanics
• Sports medicine
• Knee joint kinematics

Background:

• Posterolateral tibial fractures (PLTFs) often accompany anterior cruciate ligament (ACL) ruptures, compromising knee stability.
• The necessity of treating concomitant PLTFs in ACL-deficient knees remains unclear.

Purpose of the Study:

• To biomechanically evaluate knee kinematics in ACL-deficient states with PLTFs.
• To compare various reconstruction techniques for ACL-deficient knees with PLTFs against the native knee state.

Main Methods:

• A robotic system tested eight knees in various states: intact, ACL-deficient, ACL-deficient with PLTF, ACL reconstruction (ACLR) with PLTF, ACLR with lateral extra-articular tenodesis (LET) and PLTF, and ACLR with reconstructed PLTF.
• Simulated laxity and pivot-shift tests were performed at multiple flexion angles under constant loading.
• Anterior tibial translation (ATT), internal rotation (IR), and external rotation (ER) were measured.

Main Results:

• No ACLR state demonstrated significant differences in ATT compared to the native knee.
• ACLR with LET showed reduced IR, while ACLR with reconstructed PLTF showed increased IR compared to the native state.
• The simulated pivot-shift test revealed significantly higher ATT in ACLR with reconstructed PLTF compared to the native state; ACLR with LET showed no significant difference.

Conclusions:

• ACLR combined with LET provides superior anterior-posterior and rotational stability compared to ACLR alone or ACLR with PLTF repair.
• Repairing PLTFs ≤3 mm concurrently with ACLR does not enhance knee stability biomechanically.
• Current biomechanical evidence does not support repairing PLTF fragments ≤3 mm during ACLR.