title: Biomechanical comparison of hamstring tendon fixation devices for anterior cruciate ligament reconstruction: part 1. Five femoral devices.
abstract: We conducted a study to biomechanically compare 5 femoral hamstring tendon fixation devices commonly used in anterior cruciate ligament reconstruction. Quadrupled human semitendinosus-gracilis tendon grafts were fixed into porcine femurs using 5 separate fixation devices. For each device, 10 specimens were tested (1500-cycle loading test at 50-200 N). Specimens surviving the cyclic loading then underwent a single load-to-failure (LTF) test. Failure mode, stiffness, ultimate load, and rigidity were recorded. Two of 10 Delta screw (Arthrex), 10 of 10 Bio-TransFix (Arthrex), 10 of 10 Bone Mulch screw (Arthrotek), 10 of 10 EZLoc (Arthrotek), and 10 of 10 Zip Loop (Arthrotek) devices completed the 1500-cycle loading test. Residual displacement was lowest for Bio-TransFix (4.1 mm) followed by Bone Mulch (5.2 mm), EZLoc (6.4 mm), Zip Loop (6.8 mm), and Delta (8.2 mm). Mean stiffness was significantly (P < .001) higher for Bone Mulch (218 N/mm) than for Bio-TransFix (171 N/mm), EZLoc (122 N/mm), Zip Loop (105 N/mm), or Delta (84 N/mm). Mean LTF was significantly ( P < .001) higher for Bone Mulch (867 N) than for Zip Loop (615 N), Bio-TransFix (552 N), EZLoc (476 N), or Delta (410 N). The Bone Mulch screw demonstrated superior strength in the fixation of hamstring grafts in the femur. Bio-TransFix was close behind. The Delta screw demonstrated poor displacement, stiffness, and LTF. When used as the sole femoral fixation device, a device with low LTF, decreased stiffness, and high residual displacement should be used cautiously in patients undergoing aggressive rehabilitation.
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, Charlotte, NC. bpscannell@gmail.com.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Scannell
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: Loeffler
authors.forename: Michael
authors.initials: M
authors.lastname: Hoenig
authors.forename: Richard D
authors.initials: RD
authors.lastname: Peindl
authors.forename: Donald F
authors.initials: DF
authors.lastname: D'Alessandro
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Connor
authors.forename: James E
authors.initials: JE
authors.lastname: Fleischli
mesh_terms: D000818:Animals; D059549:Anterior Cruciate Ligament Reconstruction / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D005269:Femur / Q000503:physiopathology / Q000601:surgery*; D064593:Heterografts / Q000503:physiopathology; D016268:Internal Fixators; D023421:Models, Animal; D013552:Swine; D013710:Tendons / Q000503:physiopathology / Q000601:surgery*