2015 ISAKOS Biennial Congress ePoster #1265

Relationship Between the Femoral Tunnel Position and the Tension Change Pattern of the Graft in the Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

Hiroshi Takuwa, MD, Izumo, Shimane JAPAN
Nobuyuki Kumahashi, MD, PhD, Izumo, Shimane JAPAN
Suguru Kuwata, MD, PhD, Hamada, Shimane JAPAN
Yuji Uchio, MD, PhD, Izumo, Shimane JAPAN

Department of Orthopaedic Surgery, Shimane uUniversity of Medicine, Izumo, Shimane, JAPAN

FDA Status Not Applicable

Summary: In the anatomic double-bundle ACL reconstruction, it is difficult to calculate the graft tension change pattern in knee flexion-extension exactly from the femoral tunnel position in particular in the posterior lateral bundle.

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Abstract:

Background

Tunnel position plays very important role for successful double-bundle anterior cruciate ligament (ACL) reconstruction. Although it is generally accepted that the femoral tunnel position affects a tension change pattern in knee flexion-extension, relationship between the femoral tunnel position and the graft tension pattern in vivo is not clear.

Purpose

To evaluate relationship between the femoral tunnel position and the graft tension change in knee flexion-extension.

Methods

Sixty five patients (mean age 28±11 years) underwent anatomic double-bundle ACL reconstruction. Grafts were fixed at ninety degrees knee flexion. Applied tensions to the anterior medial bundle (AMB) and the posterior lateral bundle (PLB) were 30 N and 10 N, respectively. The femoral tunnel positions of the AMB and PLB were assessed by three-dimensional computed tomography (3D-CT) according to the quadrant method in a week after surgery. Tension changes in knee flexion-extension were assessed by the digital tension meter during surgery. Relationship between the femoral tunnel position and the tension change were evaluated via the multiple regression analysis.

Results

The center of the AMB was at 25.4±4.7% in a deep-shallow direction and at 16.3±6.2% in a high-low direction on average, and the center of the PLB was at 30.8±5.0% in a deep-shallow direction and at 44.5±7.1% in a high-low direction on average. All tunnels were created posterior to the intercondylar ridge. Tension changes in the AMB and the PLB were 33.0±18.9 N and 58.6±32.0 N on average, respectively. Although height of the AMB was weekly correlated with tension change(R=0.355, p=0.044), depth of the PLB was not correlated (p=0.128). Depth and height of the PLB were not correlated with tension change(R=0.146, p=0.36 and 0.58, respectively).

Conclusion

In the anatomic double-bundle ACL reconstruction, it is difficult to calculate the graft tension change pattern in knee flexion-extension exactly from the femoral tunnel position in particular in the PLB. This results shows that tension change may be too high, even if the femoral tunnel is created in anatomic position. We believe that to assess the graft tension pattern in operation is very important to avoid the overload of the graft that may lead a cartilage injury or the looseness that may lead a knee instability.