Tibial Tunnel Placement for ACL Reconstruction

Although extensive research has been carried out on Anterior Cruciate Ligament (ACL) femoral tunnel placement, very little attention has been given to the tibial tunnel. Researchers have suggested that the tibial tunnel be placed in the center of the ACL footprint, which they described as being approximately 43% of the way (anterior-to-posterior) across the proximal tibia at its widest extent. However, others have suggested that a more anterior placement may yield improved biomechanical and clinical results. The center of the ACL footprint and the posterior aspect of the anterior horn of the lateral meniscus does not yield tibial tunnel placement a consistent percentage of the way across the tibial plateau; therefore, guidelines should be based on intraoperative fluoroscopic measurements. However, the question remaining is what percentage of the anterior-to-posterior distance across the tibia is the ideal location for the tibial tunnel in ACL reconstruction. This study will help answer that question. Patients with a diagnosed rupture of the ACL who are scheduled for surgical reconstruction will be considered for enrollment. Eligible patients will be allocated to one of two groups based on the location of the tibial tunnel (anterior vs. posterior) during the surgical procedure. In addition to a baseline (pre-operative) evaluation, participants will return for follow-up visits at 6, 12, and 24 months post-surgery. Follow up will be completed at 24 months. The primary objective of this study is to collect subjective and objective measures of knee-related function in patients with an anterior vs. posterior placed tibial tunnel through 24 months postoperative care.

During surgery prior to ACL reconstruction, a line will be measured to indicate 35% of the anterior-to-posterior (front to back) distance of the proximal tibia. The tibial tunnel will be placed anterior (in front) of the 35% line.

During surgery prior to ACL reconstruction, a line will be measured to indicate 35% of the anterior-to-posterior (front to back) distance of the proximal tibia. The tibial tunnel will be placed posterior (in back) of the 35% line.

ACL reconstruction with anterior tibial tunnel placement in reference to a point measuring 35% of the anterior-posterior distance of the proximal tibia.

ACL reconstruction with posterior tibial tunnel placement in reference to a point measuring 35% of the anterior-posterior distance of the proximal tibia.

Inclusion Criteria: Age at time of randomization: 16 - 50 years (skeletally mature) Primary, uncomplicated ACL reconstruction Autograft (STG or BPTB) Exclusion Criteria: Multiple ligament knee injury (full thickness) Revision ACL reconstruction ACL reconstruction with allograft Meniscectomy > 75% Treatable articular cartilage lesions Diagnosis of tibiofemoral or patellofemoral osteoarthritis (Kellgren Lawrence grade > II) Valgus alignment on long-leg cassette (weight bearing line outside of joint center) Prior surgery in the ankles, knees, or hips Clinical evidence of hip disease Patellofemoral joint instability Significant patellar or tibiofemoral mal-alignment BMI > 35 Type 1 Diabetes Mellitus Known connective tissue disorder (e.g. Ehlers-Danlos) Peripheral neuropathy Neurovascular/ circulatory disorder Any form of inflammatory arthritis (e.g. rheumatoid arthritis, gout, pseudogout, lupus, etc.) Significant co-morbid conditions as determined by the investigator (e.g. malignancy, renal, hepatic disease, etc.) Known or suspected psychological disorder

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Hatayama K, Terauchi M, Saito K, Higuchi H, Yanagisawa S, Takagishi K. The importance of tibial tunnel placement in anatomic double-bundle anterior cruciate ligament reconstruction. Arthroscopy. 2013 Jun;29(6):1072-8. doi: 10.1016/j.arthro.2013.02.003. Epub 2013 Apr 6.