TY - JOUR
T1 - A Biomechanical Analysis of Interference Screw Versus Bone Tunnel Fixation of Flexor Hallucis Longus Tendon Transfers to the Calcaneus
AU - Liu, George T.
AU - Balldin, B. Christian
AU - Zide, Jacob R.
AU - Chen, Christopher T.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - The flexor hallucis longus tendon transfer is commonly used to restore function in chronic Achilles tendon ruptures and chronic Achilles tendinopathy. The tendon is often secured to the calcaneus either through a bone tunnel or by an interference screw. We hypothesized that tenodesis using the bone tunnel method would be mechanically superior to interference screw fixation for flexor hallucis longus transfers. Eight matched pairs of cadaveric specimens were assigned randomly to the bone tunnel or interference screw technique and were loaded to failure. Biomechanical analysis was performed to evaluate the ultimate strength, peak stress, Young's modulus, failure strain, and strain energy. Unpaired comparison, paired comparison, and linear regression analyses were used to determine statistical significance. A slight 22% ± 9% decrease in Young's modulus and a 52% ± 18% increase of strain energy were found in the interference screw group. However, no differences in ultimate strength, peak stress, or failure strain were seen between the 2 groups on paired comparison. Our findings suggest that interference screw fixation provides similar spontaneous biomechanical properties to the use of a bone tunnel for flexor hallucis longus transfer to the calcaneus. The interference screw is a practical option for fixation of the flexor hallucis longus tendon to the calcaneus and can be performed through a single incision approach.
AB - The flexor hallucis longus tendon transfer is commonly used to restore function in chronic Achilles tendon ruptures and chronic Achilles tendinopathy. The tendon is often secured to the calcaneus either through a bone tunnel or by an interference screw. We hypothesized that tenodesis using the bone tunnel method would be mechanically superior to interference screw fixation for flexor hallucis longus transfers. Eight matched pairs of cadaveric specimens were assigned randomly to the bone tunnel or interference screw technique and were loaded to failure. Biomechanical analysis was performed to evaluate the ultimate strength, peak stress, Young's modulus, failure strain, and strain energy. Unpaired comparison, paired comparison, and linear regression analyses were used to determine statistical significance. A slight 22% ± 9% decrease in Young's modulus and a 52% ± 18% increase of strain energy were found in the interference screw group. However, no differences in ultimate strength, peak stress, or failure strain were seen between the 2 groups on paired comparison. Our findings suggest that interference screw fixation provides similar spontaneous biomechanical properties to the use of a bone tunnel for flexor hallucis longus transfer to the calcaneus. The interference screw is a practical option for fixation of the flexor hallucis longus tendon to the calcaneus and can be performed through a single incision approach.
KW - bone tunnel
KW - cadaver study
KW - chronic Achilles tendon rupture
KW - flexor hallucis longus tendon transfer
KW - interference screw
KW - neglected Achilles tendon rupture
KW - tenodesis
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U2 - 10.1053/j.jfas.2017.04.014
DO - 10.1053/j.jfas.2017.04.014
M3 - Article
C2 - 28633783
AN - SCOPUS:85020852239
SN - 1067-2516
VL - 56
SP - 813
EP - 816
JO - Journal of Foot and Ankle Surgery
JF - Journal of Foot and Ankle Surgery
IS - 4
ER -