Adjustable-Loop Femoral Cortical Suspensory Fixation for Patellar Tendon Anterior Cruciate Ligament Reconstruction: A Time Zero Biomechanical Comparison With Interference Screw Fixation.

Journal Article (Journal Article)

BACKGROUND:Adjustable-loop cortical buttons for femoral fixation of bone-tendon-bone grafts have potential advantages over interference screw fixation; however, these devices have not been benchmarked biomechanically against interference screws. Purpose/Hypothesis: The purpose was to compare the time zero biomechanical properties of commercially available, adjustable-loop cortical button and metallic interference screws for femoral fixation of bone-tendon-bone grafts. It was hypothesized that no significant differences would be found in biomechanical properties between fixation techniques. STUDY DESIGN:Controlled laboratory study. METHODS:Adjustable-loop cortical buttons (n = 8) and metallic interference screws (n = 8) were used to fix matched pairs of human bone-tendon-bone allografts in porcine distal femurs. These constructs were preconditioned (10 N to 50 N at 1 Hz, 10 cycles), subjected to cyclic loading (50 N to 250 N at 1 Hz, 500 cycles), and then pulled to failure at 20 mm/min. RESULTS:The loads to failure (mean ± SD, 700 ± 256 N vs 688 ± 215 N, P = .92) and linear stiffnesses (219 ± 48 N/mm vs 218 ± 49 N/mm, P = .97) for the adjustable-loop cortical button and metallic interference screws, respectively, were not significantly different. Cyclic displacement was higher in the adjustable-loop cortical button group (2.1 ± 0.6 mm vs 1.3 ± 0.4 mm, P = .01). The mechanism of failure was different between groups, with bone block slippage occurring most commonly in the interference screw group (n = 5) and fracture of the bone block through the suture hole occurring most commonly in the adjustable-loop cortical button group (n = 6). CONCLUSION:Adjustable-loop cortical buttons and interference screws have similar time zero failure loads, although cyclic displacement was higher with the adjustable-loop cortical buttons. The mean difference in displacement was less than 1 mm compared with the interference screw. CLINICAL RELEVANCE:Adjustable-loop cortical buttons may be an acceptable alternative to an interference screw for femoral fixation of bone-tendon-bone grafts in anterior cruciate ligament reconstruction. The clinical relevance of the observed differences in cyclic displacement is unknown and should be evaluated in future studies.

Full Text

Duke Authors

Cited Authors

  • Mickelson, DT; Lefebvre, T; Gall, K; Riboh, JC

Published Date

  • July 2018

Published In

Volume / Issue

  • 46 / 8

Start / End Page

  • 1857 - 1862

PubMed ID

  • 29763336

Electronic International Standard Serial Number (EISSN)

  • 1552-3365

International Standard Serial Number (ISSN)

  • 0363-5465

Digital Object Identifier (DOI)

  • 10.1177/0363546518771365


  • eng