Altered Knee Loading Following Primary ACL Repair versus ACL Reconstruction

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Biomechanics

Background:

• Anterior Cruciate Ligament (ACL) repair (ACL-r) is gaining interest for ACL tears.
• Potential benefits include preserving native ACL innervation/blood supply and reducing graft site morbidity.
• ACL-r may improve knee biomechanics and decrease osteoarthritis risk compared to ACL reconstruction (ACL-R).

Purpose of the Study:

• To compare knee joint loading during a single limb squat task.
• To assess differences between primary ACL repair (ACL-r) and standard ACL reconstruction (ACL-R) using patellar bone-tendon-bone autograft.

Main Methods:

• A case-control study comparing 15 patients in the ACL-r group with 15 in the ACL-R group.
• Biomechanical testing (peak knee extension moment, total knee joint power) and IKDC questionnaire at 12 weeks post-op.
• Quadriceps strength testing using an isokinetic dynamometer at 3 months post-op; Limb Strength Index (LSI) calculated for all variables.

Main Results:

• ACL-r group showed significantly greater peak knee extension moment LSI (78.5% vs 56.9%) and total knee joint power LSI (72.5% vs 39.7%) compared to ACL-R.
• Quadriceps LSI was also significantly greater in the ACL-r group (66.3% vs 48.0%).

Conclusions:

• Patients undergoing ACL repair (ACL-r) exhibit improved knee joint loading symmetry during single-leg squats.
• Greater quadriceps strength symmetry was observed in the ACL-r group compared to the ACL-R group at 12 weeks.
• ACL-r may lead to better functional recovery and knee biomechanics post-surgery.