Cyclic Loading of Sacroiliac Screws in Tile C Pelvic Fractures

Biomedical Physics and Technology, Erasmus University Rotterdam, The Netherlands.
The Journal of trauma (Impact Factor: 2.96). 06/2005; 58(5):1029-34. DOI: 10.1097/01.TA.0000158515.58494.11
Source: PubMed


To investigate the stiffness and strength of completely unstable pelvic fractures fixated both anteriorly and posteriorly under cyclic loading conditions, the authors conducted a randomized, comparative, cadaveric study.
In 12 specimens, a Tile C1 pelvic fracture was created. The authors compared the intact situation to anterior plate fixation combined with one or two sacroiliac screws. In 2,000 measurements, each pelvis was loaded with a maximum of 400 N. The translation and rotation stiffness of the fixations were measured using a three-dimensional video system. Furthermore, the load to failure and the number of cycles before failure were determined.
Both translation and rotation stiffness of the intact pelvis were superior to the fixated pelvis. No difference in stiffness was found between the techniques with one or two sacroiliac screws. However, a significantly higher load to failure and significantly more loading cycles before failure could be achieved using two sacroiliac screws compared with one screw.
Although the combination of anterior plate fixation combined with two sacroiliac screws is not as stable as the intact pelvis, in this study, embalmed aged pelves could be loaded repeatedly with physiologic forces. Given the fact that the average trauma patient is younger and given the fact that the quality (or grip) of the fixation was a significant covariable for longer endurance of the fixation, this suggests that direct postoperative weight bearing could be possible if these results are confirmed in further research.

Download full-text


Available from: Arie B van Vugt
  • [Show abstract] [Hide abstract]
    ABSTRACT: Frakturen des Beckens bei Vorliegen einer Osteoporose gewinnen zunehmend an Bedeutung. Sie stellen den Chirurgen aufgrund der häufig verminderten Knochenqualität vor Probleme. Im Rahmen dieser Übersicht werden die Studienergebnisse relevanter biomechanischer Arbeiten für instabile Beckenringfrakturen und die vorliegenden Arbeiten zur Biomechanik von Osteosynthesen bei Azetabulumfrakturen diskutiert. Fractures of the pelvis are of increasing interest, especially in older patients due to the often concomitant osteoporosis. The low bone quality can be a problem in several fixation situations. In this review the present and relevant literature on biomechanical data of unstable pelvic ring injuries and all biomechanical data dealing with osteosynthesis for acetabular fractures are discussed. SchlüsselwörterBeckenringfraktur-Azetabulumfraktur-Biomechanik-Osteosynthese KeywordsPelvic ring fracture-Acetabular fracture-Biomechanics-Osteosynthesis
    No preview · Article · Apr 2010 · Der Unfallchirurg
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we have observed and analyzed the drilling process with femtosecond laser on the silicon surface in order to investigate a degree of thermal effect during the dicing process of the thin silicon substrate
    No preview · Article · Jan 2005
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Artificial calcanei, fresh-frozen cadaver specimens, and embalmed cadaver specimens were compared in experimental testing under biocompatible loading to clarify the biocompatibility of artificial calcaneal specimens for implant testing. Two different artificial calcaneal bone models (Sawbone, Pacific Research Laboratories, Vashon, WA, and Synbone, Synbone Inc., Davos, Switzerland), embalmed cadaver calcaneal specimens (bone density, 313.1 +/- 40.9 g/cm2; age, 43.8 +/- 7.9 years), and fresh-frozen cadaver calcanei (bone density, 238.5 +/- 30.0 g/cm2; age, 44.4 +/- 8.2 years) were used for testing. Seven specimens of each model or cadaver type were tested. A mechanical testing machine (Zwick Inc., Ulm, Germany) was used for loading and measurements. Cyclic loading (preload 20 N, load was increased every 100 cycles by 100 N from 1,000 to 2,500 N, 0.5 mm/s) and load to failure (0.5 mm/s) were performed. The loads were applied through an artificial talus in a physiological loading direction. The displacement of the posterior facet in the primary loading direction was measured. The four different specimen groups showed different stability and different displacement in the primary loading direction during cyclic loading. The variation of the maximal displacement in the primary loading direction for the entire cyclic loading was higher in artificial specimens than in the cadaver specimens. Artificial calcanei (Sawbone, Synbone) showed different biomechanical characteristics than cadaver bones (embalmed and fresh-frozen) in this experimental setup with biocompatible cyclic loading. These results do not support the use of artificial calcanei for biomechanical implant testing. Fresh-frozen and embalmed specimens seem to be equally adequate for mechanical testing. The low variation of mechanical strength in the unpaired cadaver specimens suggests that the use of PAIRED specimens is not necessary.
    Full-text · Article · Jan 2007 · Foot & Ankle International
Show more