ACL graft migration under cyclic loading

Knee Surg Sports Traumatol Arthrosc. 2010 Aug;18(8):1065-70. doi: 10.1007/s00167-009-0970-2. Epub 2009 Oct 28.

Abstract

Elongation and migration of ACL grafts will lead to a deterioration of the initial stability of ACL reconstructions. The graft migration has been sparsely investigated independently from the elongation of the graft-fixation complex. The hypothesis of this investigation was that cyclic tensile loads cause a measurable migration of the grafts. Three graft/fixation combinations were investigated in human femora (n = 7): human bone-patellar tendon grafts fixed with a biointerference screw (BPTG-IS) and free tendon grafts (porcine) fixed with either a Bio-TransFix pin (FTG-TF) or an Endobutton CL (FTG-EB). The grafts were fitted with tantalum markers. Then, the specimens were repetitively loaded (50-250 N, 800 cycles). The marker position was fluoroscopically determined at defined intervals and the migration calculated from the change in position relative to a fiducial marker within the bone. A migration of the grafts occurred in all three groups. The migration in the FTG-EB group was significantly larger than in the two other groups (P < 0.01). After 800 cycles, average migration was 0.3 (+/-0.2) mm in the BPTG-IS group, 0.7 (+/-0.4) mm FTG-TF group, 2.0 (+/-1.3) mm in the FTG-EB group. This migration might contribute to a loss of initial stability. Because the graft migration was dependent on the technique, the presented data might provide additional arguments for making the decision on the most appropriate graft/fixation combination.

MeSH terms

  • Adult
  • Aged
  • Animals
  • Anterior Cruciate Ligament / diagnostic imaging
  • Anterior Cruciate Ligament / surgery*
  • Bone-Patellar Tendon-Bone Grafting*
  • Femur / diagnostic imaging
  • Femur / surgery
  • Fluoroscopy
  • Humans
  • Materials Testing
  • Middle Aged
  • Orthopedic Fixation Devices
  • Swine
  • Tendons / transplantation*
  • Tensile Strength*
  • Weight-Bearing*