Biomechanical analysis of fracture healing in guinea-pigs.
To validate the hypothesis that healing of fractures can be accelerated by oral administered L-arginine a guinea-pig model was chosen. A diaphyseal defect fracture was established in the right femur of each of the 32 small animals and stabilized. According to randomization groups the oral administration was realized (2 or 4 weeks medication / solvent). The following biomechanical variables were measured after 4 weeeks in 32 right femora and the corresponding uninjured left femora. The measurement for the healed femur was individually compared with that of the uninjured femur in each animal; bending, force (necessary for refracture) and energy (necessary for refracture). To apply the bending moment in a measurable and reproducible way each end of the femur was secured using a special device. For each femur a strain/momentum graph of the measurements and the essential parameters were drawn (stiffness, end of the linear range, and failure-point). The bending moment was always applied with the same loading rate. The following three variables were used for the biomechanical evaluation; bending stiffness, force until failure and energy necessary for refracture. The bending stiffness reached 73% by the control group and 88% by the 4-week treatment group. The force necessary for refracture was 52% in the control compared with 65% in the 4-week treatment group. The energy necessary for refracture was 36% in the control compared with 73% in the group treated for 4 weeks. The 2 week treatment group showed no statistical significant differences to the control, but the femora from the 4 week treatment group required statistically significant higher energy for refracture than the femora from the control.
Kdolsky
Richard
R
Department of Traumatology, University of Vienna Medical School, Austria.
Reihsner
Roland
R
Beer
Rudolf
R
D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D001696:Biomechanical Phenomena; D005269:Femur / Q000293:injuries*; D017102:Fracture Healing / Q000502:physiology*; D050723:Fractures, Bone / Q000534:rehabilitation*; D006168:Guinea Pigs; D008297:Male; D023421:Models, Animal; D012008:Recurrence; D012307:Risk Factors; D013314:Stress, Mechanical
D001120:Arginine