title: Initial fixation strength of bioabsorbable and titanium interference screws in anterior cruciate ligament reconstruction. Biomechanical evaluation by single cycle and cyclic loading.
abstract: We evaluated the initial bone-patellar tendon-bone graft fixation strength of bioabsorbable as compared with titanium interference screws in anterior cruciate ligament reconstruction using matched pairs of porcine knees. Ten pairs underwent single-cycle failure loading at a rate of 50 mm/min, and 10 pairs underwent cyclic loading at half-hertz frequency. The cyclic loading started with 100 load cycles between 50 and 150 N. We then progressively increased loads in 50-N increments after each set of 100 cycles. After 100 cycles at 850 N, the specimens were loaded to failure at a rate of 50 mm/min. In the single-cycle failure loading test, the mean ultimate failure loads (+/-SD) for the bioabsorbable (837 +/- 260 N) and titanium interference screws (863 +/- 192 N) were not significantly different, nor were the mean yield loads or the stiffness of the fixation. In the cyclic loading test, the yield loads were 605 +/- 142 N and 585 +/- 103 N for the bioabsorbable and titanium interference screws, respectively (no significant difference). Although there was no significant difference in the ultimate failure load, more bone block fractures were found in the grafts fixed with a titanium interference screw. Bioabsorbable interference screw fixation thus seems to provide a reasonable alternative to titanium screws.
authors.affiliation: Medical School and Institute of Medical Technology, University of Tampere, and Tampere University Hospital, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Kousa
authors.forename: T L
authors.initials: TL
authors.lastname: Järvinen
authors.forename: P
authors.initials: P
authors.lastname: Kannus
authors.forename: M
authors.initials: M
authors.lastname: Järvinen
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery* / Q000637:transplantation; D001696:Biomechanical Phenomena; D001863:Bone Screws; D019544:Equipment Failure Analysis; D066298:In Vitro Techniques; D008422:Materials Testing; D019651:Plastic Surgery Procedures / Q000295:instrumentation*; D013552:Swine; D013718:Tensile Strength; D013977:Tibia / Q000601:surgery; D014025:Titanium; D016474:Weight-Bearing
chemical_list: D014025:Titanium