Shallow knee flexion angle during femoral tunnel creation using modified transtibial technique can reduce femoral graft bending angle in ACL reconstruction
- 90 Downloads
The purpose of this study was to compare femoral graft bending angle between patients with femoral tunnel reamed at less than 80° of knee flexion and those with 80° and above in anatomical anterior cruciate ligament (ACL) reconstruction using modified transtibial technique.
Forty-eight patients who underwent ACL reconstruction using bone–patellar-tendon–bone autograft in modified transtibial technique and CT scan at 1 week postoperatively were included in this study. A femoral guidewire insertion into aimed femoral position at the medial wall of the femoral lateral condyle was started at about 75° of knee flexion. When the tip of the guidewire was blown out into femoral posterior wall, the guidewire was inserted again after increasing knee flexion angle. Distance from femoral tunnel exit on the femoral lateral cortex–femoral posterior cortex (Distance-E) was measured on postoperative lateral radiograph. Femoral and tibial tunnel position was measured on 3-D CT images. In addition, femoral graft bending angle was measured on reconstructed 2-D CT images. Patients were divided into two groups depending on whether femoral tunnel was created at less than 80° of knee flexion (group A) or 80° or more (group B).
There were 32 patients in group A and 16 patients in group B, respectively. Average knee flexion angle was 77.2° [standard deviation (SD) 1.6] in group A and 83.6° (SD 2.4) in group B, respectively (p < 0.05). Average Distance-E was 5.1 mm (SD 2.6) in group A and 6.6 mm (SD 3.8) in group B, respectively. There was no significant difference in the femoral and tibial tunnel position between group A and B. Femoral graft bending angle was significantly smaller in group A [average angle: 50.9° (SD 6.6)] than in group B [average angle: 55.0° (SD 6.6)] (p < 0.05).
Anatomical femoral tunnel was able to be created at less than 80° of knee flexion in two-thirds of patients. Shallower flexion angle (less than 80°) provided gentler femoral graft bending angle compared to 80° or more of knee flexion. Therefore, femoral tunnel creation in modified transtibial technique should be started at between 75° and 80° of knee flexion to reduce femoral graft bending angle. Shallow knee flexion angle during femoral tunnel creation using modified transtibial technique can reduce femoral graft bending angle and may lead to better clinical outcomes in ACL reconstruction.
Levels of evidence
Retrospective comparative study, Level III.
KeywordsAnterior cruciate ligament Graft bending angle Transtibial Bone–patellar tendon–bone autograft
We appreciate the guidance of Dr. Shigeo Fukuoka, Nishigima Hospital, Japan. Modified transtibial technique in this study was performed based on the technique designed by Dr. Fukuoka.
No external funding was used.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest associated with this manuscript.
This study was approved by the Shimada Hospital Institutional Review Board (ID number of approval: 2017-002).
Informed consent was obtained from all subjects.
- 4.Robin BN, Jani SS, Marvil SC, Reid JB, Schillhammer CK, Lubowitz JH (2015) Advantages and disadvantages of transtibial, anteromedial portal, and outside-in femoral tunnel drilling in single-bundle anterior cruciate ligament reconstruction: a systematic review. Arthroscopy 31:1412–1417CrossRefPubMedGoogle Scholar
- 9.Nohmi S, Ishibashi Y, Tsuda E, Yamamoto Y, Tsukada H, Toh S (2012) Biomechanical comparison between single-bundle and double-bundle anterior cruciate ligament reconstruction with hamstring tendon under cyclic loading condition. Sports Med Arthrosc Rehabil Ther Technol 4:23CrossRefPubMedGoogle Scholar
- 13.Tashiro Y, Gale T, Sundaram V, Nagai K, Irrgang JJ, Anderst W, Nakashima Y, Tashman S, Fu FH (2017) The graft bending angle can affect early graft healing after anterior cruciate ligament reconstruction: in vivo analysis with 2 years’ follow-up. Am J Sports Med 45:1829–1836CrossRefPubMedGoogle Scholar
- 17.Osaki K, Okazaki K, Tashiro Y, Matsubara H, Iwamoto Y (2015) Influences of knee flexion angle and portal position on the location of femoral tunnel outlet in anterior cruciate ligament reconstruction with anteromedial portal technique. Knee Surg Sports Traumatol Arthrosc 23:777–784CrossRefPubMedGoogle Scholar
- 18.Śmigielski R, Zdanowicz U, Drwięga M, Ciszek B, Ciszkowska-Łysoń B, Siebold R (2015) Ribbon like appearance of the midsubstance fibres of the anterior cruciate ligament close to its femoral insertion site: a cadaveric study including 111 knees. Knee Surg Sports Traumatol Arthrosc 23:3143–3150CrossRefPubMedGoogle Scholar
- 27.Niki Y, Nagai K, Harato K, Suda Y, Nakamura M, Matsumoto M (2017) Effects of femoral bone tunnel characteristics on graft-bending angle in double-bundle anterior cruciate ligament reconstruction: a comparison of the outside-in and transportal techniques. Knee Surg Sports Traumatol Arthrosc 25:1191–1198CrossRefPubMedGoogle Scholar
- 28.Park JS, Park JH, Wang JH, Oh CH, Hwang MH, Lee SH, Kim JG (2015) Comparison of femoral tunnel geometry, using in vivo 3-dimensional computed tomography, during transportal and outside-in single-bundle anterior cruciate ligament reconstruction techniques. Arthroscopy 31:83–91CrossRefPubMedGoogle Scholar