[The effect of the tibial tunnel fixation level on the results of cyclic loading in anterior cruciate ligament reconstruction]. / On çapraz bag rekonstrüksiyonunda tibial tünel tespit seviyesinin tekrarlayici yüklenme testi sonuçlarina etkisi.

OBJECTIVES: This study was designed to compare the biomechanical characteristics of non-anatomic (far from joint) and anatomic (close to joint) levels of tibial tunnel fixation with soft tissue graft using a soft tissue interference screw in anterior cruciate ligament (ACL) reconstruction. METHODS: Twelve bovine tibiae and digital extensor tendons were divided into two homogeneously equal groups after removing soft tissues. Tibial tunnels were prepared with a 7-mm drill with the use of an ACL guide adjusted to 45 degrees . Each tunnel was then dilated to 9 mm in 0.5 mm increments. Digital extensor tendons were fixed at non-anatomic (group I) or anatomic (group II) tibial tunnel levels with a soft tissue metal interference screw, 9 x 30 mm in size. All the specimens were cycled 500 times from 50 to 250 N with 1 Hz frequency in a servo-hydraulic testing machine followed by ultimate load at-failure testing at a rate of 20 mm/min. Statistical analyses were made using the Mann-Whitney U-test. RESULTS: The mean screw insertion torque values were 8.2+/-2.4 Nm and 7.8+/-2.3 Nm in groups I and II, respectively (p=0.88). The mean values of graft displacement (1.9+/-0.75 mm versus 2.2+/-1.2 mm, p=0.63) and stiffness (132.72+/-10.93 N/mm versus 125.14+/-15.93 N/mm, p=0.63) did not differ significantly. CONCLUSION: The biomechanical properties of ACL reconstruction with soft tissue graft fixation using a soft tissue interference screw are not influenced by the level of tibial tunnel fixation.

[The effect of anterior or posterior tibial tunnel placement of a soft tissue graft with a soft tissue interference screw on fixation biomechanics]. / On çapraz bag rekonstrüksiyonunda tendon greftinin yumusak doku interferans vidasi ile tibial tünelde öne veya arkaya tespitinin biyomekanik etkisi.

OBJECTIVES: We investigated the biomechanical characteristics of anterior or posterior tibial tunnel placement of the soft tissue graft with a soft tissue interference screw in anterior cruciate ligament (ACL) reconstruction. METHODS: Twelve bovine tibiae and digital extensor tendons were divided into two homogeneously equal groups after they were stripped of all soft tissues. Tibial tunnels were prepared and digital extensor tendons were fixed at nonanatomic (apart from the joint) anterior (n=6, group I) or posterior (n=6, group II) tibial tunnel positions with a soft tissue metal interference screw, 9x30 mm in size. All the specimens were cycled 500 times from 50 to 250 N at 1 Hz frequency in a servo hydraulic test device, after which ultimate load-at-failure testing was performed at a rate of 20 mm/min. RESULTS: The mean screw insertion torque values were 8.2+/-2.4 Nm and 8.4+/-2.8 Nm in groups I and II, respectively (p=0.88). No significant differences were found between the two groups with respect to graft displacement (1.9+/-0.8 mm vs 2.3+/-0.4 mm; p=0.38) and stiffness (132.7+/-10.9 N/mm vs 126.4+/-8.5 N/mm, p=0.98) at the end of cyclic loading. CONCLUSION: Our results show that the site of nonanatomic soft tissue graft fixation in the tibial tunnel (anterior or posterior) with a soft tissue interference screw do not affect the biomechanical parameters in ACL reconstruction.