Biomechanical evaluation of fixation of intra-articular fractures of the distal part of the radius in cadavera: Kirschner wires compared with calcium-phosphate bone cement.
BACKGROUND
The purpose of this study was to compare the biomechanical efficacy of an injectable calcium-phosphate bone cement (Skeletal Repair System [SRS]) with that of Kirschner wires for the fixation of intraarticular fractures of the distal part of the radius.


METHODS
Colles fractures (AO pattern, C2.1) were produced in ten pairs of fresh-frozen human cadaveric radii. One radius from each pair was randomly chosen for stabilization with SRS bone cement. These ten radii were treated with open incision, impaction of loose cancellous bone with use of a Freer elevator, and placement of the SRS bone cement by injection. In the ten control specimens, the fracture was stabilized with use of two horizontal and two oblique Kirschner wires. The specimens were cyclically loaded to a peak load of 200 newtons for 2000 cycles to evaluate the amount of settling, or radial shortening, under conditions simulating postoperative loading with the limb in a cast. Each specimen then was loaded to failure to determine its ultimate strength.


RESULTS
The amount of radial shortening was highly variable among the specimens, but it was consistently higher in the Kirschner-wire constructs than in the bone fixed with SRS bone cement within each pair of radii. The range of shortening for all twenty specimens was 0.18 to 4.51 millimeters. The average amount of shortening in the SRS constructs was 50 percent of that in the Kirschner-wire constructs (0.51+/-0.34 compared with 1.01+/-1.23 millimeters; p = 0.015). With the numbers available, no significant difference in ultimate strength was detected between the two fixation groups.


CONCLUSIONS
This study showed that fixation of an intra-articular fracture of the distal part of a cadaveric radius with biocompatible calcium-phosphate bone cement produced results that were biomechanically comparable with those produced by fixation with Kirschner wires. However, the constructs that were fixed with calcium-phosphate bone cement demonstrated less shortening under simulated cyclic load-bearing.
Yetkinler
D N
DN
Biomechanics Laboratory, Norian Corporation, Cupertino, California 95014-4166, USA. duran_yetkinler@norian.com
Ladd
A L
AL
Poser
R D
RD
Constantz
B R
BR
Carter
D
D
D001696:Biomechanical Phenomena; D001843:Bone Cements; D001864:Bone Wires; D002130:Calcium Phosphates / Q000008:administration & dosage*; D002484:Cementation; D003100:Colles' Fracture / Q000503:physiopathology / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D007267:Injections; D011897:Random Allocation; D013314:Stress, Mechanical; D014955:Wrist Joint / Q000503:physiopathology
D001843:Bone Cements; D002130:Calcium Phosphates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous