Rebranding the 'anatomic' ACL reconstruction: Current concepts.

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Biomechanics

Background:

• The anterior cruciate ligament (ACL) has a complex, non-uniform structure, making single cylindrical grafts insufficient for complete reconstruction.
• Current "anatomic" ACL reconstruction techniques cause confusion due to varied graft placements within the native ACL footprint.
• The "direct fibers" of the ACL, responsible for 85-95% of load-bearing, resist anterior tibial translation and internal rotation.

Purpose of the Study:

• To advocate for replacing the ambiguous term "anatomic" with precise anatomical descriptions of tunnel placement in ACL reconstruction.
• To define optimal femoral and tibial tunnel placements for restoring the native ACL's function, particularly the "direct fibers".
• To emphasize the need for reproducible techniques in ACL reconstruction for better patient outcomes.

Main Methods:

• Review of anatomical studies identifying "direct and indirect fibers" of the ACL and their insertion points.
• Analysis of existing ACL reconstruction techniques and their cited anatomical references.
• Proposal of specific femoral tunnel placement (isometric anteromedial) and tibial tunnel placement (anterior-most non-impinging) based on anatomical findings.

Main Results:

• The native ACL footprint is significantly larger than typical grafts, allowing for multiple potential tunnel placements.
• Optimal femoral tunnel placement should focus on restoring the insertion of the "direct fibers" just posterior to the intercondylar ridge.
• Preferred technique involves an isometric anteromedial femoral tunnel and an anterior tibial tunnel, potentially combined with lateral extra-articular tenodesis for pivot shift.

Conclusions:

• The term "anatomic" in ACL reconstruction should be abandoned in favor of detailed anatomical descriptions of tunnel positioning.
• Precise description of tunnel placement on the tibia and femur is crucial for surgical technique replication and further research.
• Further research validating specific tunnel positions with patient outcomes is necessary, requiring standardized anatomical reporting.