Original researchFixation of Osteoporotic Distal Fibula Fractures: A Biomechanical Comparison of Locking Versus Conventional Plates
Section snippets
Methods
Eight matched pairs of elderly female cadaver ankles were used for this study (age, 73–94; mean, 85). All specimens were evaluated with anteroposterior and lateral plain radiographs to determine if any gross bony abnormality existed. In addition, dual-energy x-ray absorptometry scans were performed on the distal metaphyseal tibia to quantify bone mineral density (BMD). Specimens were dissected to remove the associated soft tissues. All bony and ligamentous structures in the ankle were left
Results
We did not detect any gross osseous abnormalities in any of the 16 tibiae using visual inspection and plane radiographs. As expected, given the matched, paired study design, there was no difference in BMD between the experimental groups. Both groups had a mean BMD of 0.52 g/cm3 in the distal metaphyseal tibia. After hardware application, the locking plate and screw had a lower radial direction height (3.2 mm) than the conventional plate and screw (4.0 mm), indicating a reduced profile for the
Discussion
We have established a cadaveric model to assess fixation in elderly ankle fractures. Using this fracture model, the biomechanical properties of locking plates were compared with those of conventional plates on the distal fibula. Our locking-plate construct with 2 distal unicortical screws was mechanically equivalent to the standard plate with 3 distal screws. We found, as expected, that the fixation with the standard plates was dependent on BMD. The locking-plate fixation, however, was
Conclusion
In summary, we have demonstrated that in the setting of elderly ankle fractures, locking plates are at least equivalent biomechanically to standard plates. In contrast to the standard plates, the locking-plate construct was not dependent on BMD. Clinically, locking plates may be advantageous in patients with the most severe osteoporosis. However, exactly which patients may benefit and the cost-effectiveness of using more expensive implants remains unclear.
References (11)
- et al.
The role of a fibular nail in the management of Weber type B ankle fractures in elderly patients with osteoporotic bone—a preliminary report
Injury
(2001) - et al.
A new method of fixation in osteoporotic bone: a preliminary report
Injury
(2002) - et al.
Comparison of fixation strengths of locking head and conventional screws in fracture and reconstruction models
J Oral Maxillofac Surg
(1998) - et al.
Treatment of osteoporotic ankle fractures in the elderly: surgical strategies
Orthopedics
(2002) - et al.
Ankle fractures in the elderly: nonoperative or operative treatment
J Orthop Trauma
(1998)
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- 1
Chief Resident, Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA.
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Graduate Research Assistant, Department of Mechanical Engineering, Colorado State University, Fort Collins, CO.
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Assistant Professor, Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA.
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Professor, Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA.
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Assistant Professor, Department of Mechanical Engineering, Colorado State University, Fort Collins, CO.