Extra-articular ACL Reconstruction and Pivot Shift: In Vivo Dynamic Evaluation With Navigation

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Sports Medicine

Background:

• The pivot-shift test is a key indicator for anterior cruciate ligament (ACL) reconstruction success, correlating with patient satisfaction and functional outcomes.
• Severe rotational instability may benefit from combining intra-articular ACL reconstruction with lateral tenodesis (LT).

Purpose of the Study:

• To biomechanically evaluate the combined effects of intra-articular ACL reconstruction and extra-articular LT on knee laxity and the pivot-shift phenomenon.

Main Methods:

• A controlled laboratory study involving 20 patients undergoing anatomic single-bundle ACL reconstruction with hamstring tendons and LT.
• Two groups were compared: Group A (ACL reconstruction then LT) and Group B (LT then ACL reconstruction).
• Measurements of anterior tibial translation (ATT) and axial tibial rotation (ATR) were taken preoperatively, post-first procedure, and post-second procedure using a navigation system during static and dynamic evaluations.

Main Results:

• Both groups showed significant reductions in ATT and ATR after ACL reconstruction and LT.
• Lateral tenodesis (LT) demonstrated greater efficacy in reducing axial tibial rotation (ATR) compared to intra-articular reconstruction alone.
• The combined approach synergistically reduced dynamic ATT and ATR during the pivot-shift test.

Conclusions:

• Anatomic ACL reconstruction and LT together effectively control the pivot-shift phenomenon.
• While LT had a limited effect on static anterior tibial translation, it significantly improved rotational control.
• The synergistic action of ACL reconstruction and LT offers a promising solution for managing rotational knee instability.