Leinonen S (1), Tiainen J (1),
Kellomäki M (2), Törmälä P (3),
Waris T (1), Ashammakhi N (1).
1. Department of Surgery, Oulu University Hospital,
P.O. Box 22, FIN-90221 Oulu, Finland.
2. Institute of Biomaterials, Tampere
University
of Technology, P.O. Box 589, FIN-33101 Tampere, Finland.
Background: Several bioabsorbable internal fixation
systems are currently in use in the field of bone surgery.
Aims: To test the mechanical properties of recently
developed 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 (BioSorbFXä
) miniscrews.
Material and methods: 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 (six pairs of
4th and six pairs of 5th 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. Studentīs t-test, the Mann-Whitney
U test and Spearman’s coefficient were used for statistical evaluation.
Results: The pullout force of tacks was 135.0
± 26.1 N and that of the miniscrews was
119.3 ± 26.1 N (p = 0.04, statistically
significant difference).
Conclusions: 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.
Key words: Biosorb; Bioabsorbable; Polylactide;
Miniscrew; Tack.
