The Journal of Bone and Joint Surgery (American) 84:1579-1586 (2002)
© 2002 The Journal of Bone and Joint Surgery, Inc.
A Biomechanical Analysis of Fixation of Intra-Articular Distal Radial Fractures with Calcium-Phosphate Bone Cement
Thomas F. Higgins, MD,
Seth D. Dodds, MD and
Scott W. Wolfe, MD
Investigation performed at the Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut
Thomas F. Higgins, MD
Department of Orthopedics, University of Utah Health Sciences Center, 30 North 1900 East, Room 3B165, Salt Lake City, UT 84132-2302. E-mail address: thomas.higgins{at}hsc.utah.edu
Seth D. Dodds, MD
Department of Orthopeedics and Rehabilitation, Yale University School of Medicine, P.O. Box 208071, New Haven, CT 06520-8071
Scott W. Wolfe, MD
Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address: wolfes@hss.edu
In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from Norian Corporation. None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Background: Calcium phosphate cement has been used to treat unstable fractures of the distal end of the radius with the intent of avoiding the stiffness and morbidity associated with prolonged immobilization in a cast or external fixation. The purpose of this study was to compare the stability of the fracture fragments after fixation with augmented calcium phosphate cement with that after alternative methods of percutaneous fracture treatment.
Methods: Both an osteotomy and osteoclasis were used to create a model of an intra-articular fracture of the distal part of the radius (AO type C2) with dorsal bone loss in seven pairs of fresh-frozen upper extremities. One wrist from each pair was fixed with an external fixator and three Kirschner wires, and the contralateral wrist was fixed with calcium phosphate cement (Norian SRS) and three Kirschner wires (augmented calcium phosphate cement). Sequentially increasing loads, up to a total of 100 N, were then applied to the major flexors and extensors of the wrist. Fracture fragment motion was measured by the Optotrak three-dimensional system.
Results: Fixation with cement alone failed at the bone-cement interface at <80 N in all specimens. With use of an analysis of variance, augmented external fixation was found to provide significantly increased stability to the radial fragment compared with that provided by augmented calcium phosphate cement in four of the six axes tested (e.g., mean motion [and standard deviation] in flexion-extension was 3.0° ± 2.93° versus 11.1° ± 13.08°, respectively; p = 0.001). Augmented calcium phosphate cement was found to provide greater stability for the radial fragment than were Kirschner wires alone in three axes (e.g., mean motion in flexion-extension was 11.1° ± 13.08° versus 36.5° ± 13.03°, respectively; p = 0.001).
Conclusions: Calcium phosphate cement alone is insufficient to withstand physiologic flexion-extension motion of the wrist without supplemental wire fixation. When supplemented with Kirschner wires, fixation with bone cement is more stable than are Kirschner wires alone, but it is significantly less stable than augmented external fixation.
Clinical Relevance: When performing studies of fracture fixation strengths, it is essential to simulate the shear and rotational forces encountered during normal wrist motion. On the basis of the physiologic biomechanical testing in this study, we recommend supplemental fixation if calcium phosphate cement is chosen for fixation of unstable distal radial fractures.

CiteULike Connotea Del.icio.us Facebook Technorati Twitter What's this?
This article has been cited by other articles:

|
 |

|
 |
 
M. D. McKee
Commentary
J. Bone Joint Surg. Am.,
January 29, 2003;
85(2):
386 - 386.
[Full Text]
[PDF]
|
 |
|
|