Original Article
Biomechanical Evaluation of a Novel Application of a Fixation Device for Bone-Tendon-Bone Graft (EndoButton CL BTB) to Soft-Tissue Grafts in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

Presented at the 53rd Annual Meeting of the Orthopaedic Research Society, San Diego, California, February 11-14, 2007.
https://doi.org/10.1016/j.arthro.2010.01.007Get rights and content

Purpose

The purpose of this biomechanical study was to compare the structural properties of the flexor tendon graft connected to the EndoButton CL BTB (ECL-BTB) (Smith & Nephew Endoscopy, Andover, MA), which is newly developed to fix the bone-tendon-bone graft, with those of the same graft connected to the EndoButton CL (ECL) (Smith & Nephew Endoscopy), which is commonly used as a standard fixation device.

Methods

We randomly divided 40 porcine flexor digitorum profundus tendons into 4 groups. An ECL and an ECL-BTB were attached to the doubled tendon measuring 6 mm in diameter in groups I and II, respectively. An ECL and an ECL-BTB were attached to the doubled tendon measuring 7 mm in diameter in the same manner in groups III and IV, respectively. Tensile testing was performed with a tensile tester.

Results

The linear stiffness of the tendon-device composite (mean ± SD) was 131.8 ± 18.3 N/mm, 109.7 ± 14.9 N/mm, 132.4 ± 20.5 N/mm, and 123.8 ± 10.7 N/mm in groups I, II, III, and IV, respectively. The 2-way analysis of variance (ANOVA) showed a significant difference (P = .0058) between the ECL and the ECL-BTB. Concerning the maximum load and the elongation at failure of the tendon-device composite, the 2-way ANOVA showed no significant difference between the 2 fixation devices. Regarding the cross-sectional area, the 2-way ANOVA indicated no significant difference between the 2 fixation devices.

Conclusions

This study has shown that the maximum load of the flexor tendon graft connected to the ECL-BTB is similar to that of the ECL whereas the stiffness of the ECL-BTB is inferior to that of the ECL.

Clinical Relevance

This study has suggested that patients should not be permitted to perform vigorous activities in the early period after anterior cruciate ligament reconstruction by use of the ECL-BTB fixation technique, because of its low stiffness compared with the ECL device.

Section snippets

Study Design

We used 20 fresh-frozen hindlimbs from fully mature Landrace Lange White-Durou pigs weighing approximately 100 kg in this study, which was carried out at the Institute of Animal Experimentation, Hokkaido University School of Medicine, Sapporo, Japan, under the rules and regulations of the Animal Care and Use Committee. Two flexor digitorum profundus tendons harvested from each hindlimb were used as substitutes for the human hamstring tendon, because previous studies have shown that the material

Results

The cross-sectional area of the doubled tendon measuring 6 mm in diameter was 24.8 ± 4.9 mm2 and 26.5 ± 4.8 mm2 in group I (ECL) and group II (ECL-BTB), respectively. The cross-sectional area of the doubled tendon measuring 7 mm in diameter was 34.8 ± 5.7 mm2 and 35.9 ± 6.0 mm2 in group III (ECL) and group IV (ECL-BTB), respectively. The 2-way ANOVA indicated no significant difference (P = .4143) in the cross-sectional area between the 2 fixation devices (ECL and ECL-BTB).

On tensile testing,

Discussion

This biomechanical study was conducted to evaluate the unique clinical idea that the ECL-BTB developed for bone-tendon-bone graft fixation could be applied flexor tendon graft fixation. This study showed that there was no significant difference in the maximum load and elongation at failure of the tendon-device composite between the ECL-BTB and the ECL. Previous studies reported on the fixation strength of various hamstring tendon graft fixation devices (ECL, Bone Mulch screw [Biomet, Warsaw,

Conclusions

This study has shown that the maximum load of the flexor tendon graft connected to the ECL-BTB is similar to that of the ECL whereas the stiffness of the ECL-BTB is inferior to that of the ECL.

Acknowledgment

The authors thank Smith & Nephew Endoscopy Japan for donating the fixation devices evaluated in this study.

References (21)

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Supported by a Grant-in-Aid for Scientific Research (No. 20240045) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. The authors report no conflict of interest.

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