Cyclic loading of fractured cadaveric femurs after elastomer femoroplasty: an in vitro biomechanical study.
BACKGROUND
Elastomer femoroplasty is a novel and experimental approach in the prevention of hip fracture surgery. Previously, we published the results of an in vitro cadaveric experiment in which we showed a significant reduction of fracture displacement in treated femurs. The aim of the present study was to establish the failure loads and inter-fragmentary movement of fractured, elastomer femoroplasty treated femurs during cyclic loading.


METHODS
16 cadaveric femurs were treated with elastomer femoroplasty and fractured in a simulated fall configuration. Each specimen underwent 10 cycles with a preload of 50 N, starting with a peak load of 250 N followed by 10 cycles of 500 N and continued with 500 N increments. The crosshead speed was 2 mm/s. The failure load, the number of completed cycles, and crosshead extensions were recorded.


RESULTS
The mean failure load was 2709 N (SD 1094). The number of completed cycles until failure was 60 (SD 22). The mean translation during maximum loading was 5.25 mm (SD 0.9). At 1500 N (two times the bodyweight of a 75 kg individual) the extension was 3.16 mm.


CONCLUSIONS
Preventive elastomer femoroplasty leads to the stabilization of the proximal femur after fracture. In a single leg stance configuration, cyclic loading with mean failure loads that well exceed the peak loads during normal gait is feasible.
Leiden University Medical Center, Department of Surgery, Leiden, The Netherlands. timvandersteenhoven@gmail.com
T J
TJ
van der Steenhoven
W
W
Schaasberg
A C
AC
de Vries
E R
ER
Valstar
R G H H
RG
Nelissen
D000368:Aged; D001696:Biomechanical Phenomena; D015519:Bone Density; D001863:Bone Screws; D002102:Cadaver; D019245:Compressive Strength; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D020724:Elastomers; D005260:Female; D005264:Femoral Fractures / Q000503:physiopathology* / Q000601:surgery; D005269:Femur / Q000601:surgery; D005684:Gait; D006620:Hip Fractures / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008422:Materials Testing; D013314:Stress, Mechanical; D013718:Tensile Strength
D004129:Dimethylpolysiloxanes; D020724:Elastomers; C013830:baysilon