Mechanical evaluation of a soft tissue interference screw in free tendon anterior cruciate ligament graft fixation

Citation
Dg. Nagarkatti et al., Mechanical evaluation of a soft tissue interference screw in free tendon anterior cruciate ligament graft fixation, AM J SP MED, 29(1), 2001, pp. 67-71
Citations number
20
Categorie Soggetti
Ortopedics, Rehabilitation & Sport Medicine
Journal title
AMERICAN JOURNAL OF SPORTS MEDICINE
ISSN journal
03635465 → ACNP
Volume
29
Issue
1
Year of publication
2001
Pages
67 - 71
Database
ISI
SICI code
0363-5465(200101/02)29:1<67:MEOAST>2.0.ZU;2-V
Abstract
In this study of bioabsorbable screw fixation of free tendon grafts used in anterior cruciate ligament reconstruction, we performed load-to-failure an d cyclic loading of tendon fixation in porcine bone. Bone density measureme nts from dual photon absorptometry scans were obtained to correlate bone de nsity with fixation failure. The average density of porcine bone (1.42 g/cm (2)) was similar to that of young human bone (1.30 g/cm(2)) and significant ly higher than that of elderly human cadaveric bone specimens (0.30 g/cm(2) ). Cyclic loading was performed on free tendon grafts fixed with a bioabsor bable screw alone and on grafts fixed with a bioabsorbable screw and an anc hor (polylactic acid ball or cortical bone disk). Stiffness of fixation inc reased substantially with the addition of a cortical bone disk anchor or po lylactic acid ball compared with the interference screw alone. Tensile fixa tion strength of central quadriceps free tendon and hamstring tendon grafts were significantly superior in porcine bone of density similar to young hu man bone than in elderly human cadaveric bone. The bioabsorbable interferen ce screw yielded loads at failure comparable with traditional bone-tendon-b one and hamstring tendon fixation when controlled for bone density. The add ition of a cortical bone disk anchor provided the mast optimal fixation of free tendon with the bioabsorbable screw and reduced slippage with cyclic l oading to a very low level.