Holding Power of Bioabsorbable Self-Reinforced Poly-L/DL-Lactide 70/30 Tacks and Miniscrews in Human Cadaver Bone

Abstract

Several bioabsorbable internal fixation systems are currently in use in the field of bone surgery. To test the mechanical properties of recently developed amorphous self-reinforced poly-L/DL-lactide [SR-P(L/DL)LA] 70/30 tacks in comparison with commercially available SR-P(L/DL)LA 70/30 (BioSorbFX; Bionx Implants Ltd) miniscrews, SR-P(L/DL)LA miniscrews (length = 6.0 mm, core diameter = 1.5 mm, thread diameter = 2.0 mm) and tacks (length = 5.4 mm, core diameter = 1.5 mm, thread diameter = 2.0 mm) were applied to human cadaveric metatarsal (MT) bones (6 pairs of fourth MT bones and 6 pairs of fifth MT bones from donors who were from 29 to 56 years of age at the time of death). Pullout force was measured using a mechanical testing machine. Forty-eight pullout tests were carried out for each implant type. The Student test, Mann-Whitney test, and Spearman coefficient were used for statistical evaluation. The pullout force of tacks was 135.0 +/- 26.1 N, and that of the miniscrews was 119.3 +/- 26.1 N ( = 0.04, statistically significant difference). Accordingly novel SR-P(L/DL)LA 70/30 tacks have a statistically better pullout strength than the SR-P(L/DL)LA 70/30 miniscrews when tested in cadaver MT bones.

Pullout strength of a biodegradable free form osteosynthesis plate

“…Biodegradable plates have to be thicker than titanium plates to achieve the same stability as titanium (Tormala et al, 1987;Wittenberg et al, 1991;Suuronen et al, 1992aSuuronen et al, , b, 1998Tormala, 1992;Ferguson et al, 1996a, b;Shetty et al, 1997;Maurer et al, 2001;Leinonen et al, 2003).…”

“…The advantage of biodegradable materials is the degradation of the material over a period of 12e24 months. Until now, biodegradable materials have had to be thicker than titanium to achieve the same mechanical stability (Ferguson et al, 1996a, b;Maurer et al, 2001;Leinonen et al, 2003). This has resulted in surgeons' and patients' complaints regarding the bulkiness of the material especially in the first six postoperative months.…”

Use of Bioabsorbable Osteofixation Devices in the Hand

“…With this technique, SR-P(L/DL)LA 70/30 minitacks have been used successfully instead of screws to stabilize cranial bone grafts with bioabsorbable plates (Serlo et al, 2002). When tested in human cadaver metatarsal bones, SR-P(L/DL)LA 70/30 minitacks required a significantly higher pullout force than corresponding SR-P(L/ DL)LA 70/30 screws (Leinonen et al, 2003).…”

Pull-Out Strength of Multifunctional Bioabsorbable Ciprofloxacin-Releasing Polylactide-Polyglycolide 80/20 Tacks

“…Also, in our earlier pull-out studies, the most common reason for failure with BioSorbPDX (SR-PLGA 80/20) tacks and SR-P(L/D)LA 70/30 tacks was barb breakage. 8,12 With screws, the most common reason for failure in pull-out tests was thread breakage with BioSorbPDX (SR-PLGA 80/20) screws and stem splitting with Lactosorb (PLGA 82L/18G) screws (LactoSorb, Warsaw, IN). 12 With ciprofloxacin-containing SR-PLGA 80/20 screws, the most common cause of failure was breakage of the screw shaft.…”