Biomechanical Comparison of 4.0-mm Short-Threaded Cannulated Screws and 4.0-mm Short-Threaded Cancellous Screws in a Canine Humeral Condylar Fracture Model.

Authors: 
Rochereau P, Diop A, Maurel N, Bernarde A.
Volume: 
41
Number: 
6
Pages: 
712-19
Journal: 
Vet Surg
Date: 
August 2012

OBJECTIVE:
To compare biomechanical properties of a humeral condylar fracture model stabilized either with a 4.0-mm short-threaded cancellous screw (CCS) or with a 4.0-mm short-threaded cannulated screw (CNS).
STUDY DESIGN:
In vitro biomechanical study.
SAMPLE POPULATION:
Bilateral cadaveric canine humeri (n = 20).
METHODS:
Fractures of the lateral portion of the humeral condyle were simulated by standardized osteotomies; 10 condyles were each stabilized with CCS and 10 with CNS. Axial compression load was applied to each specimen until failure and force-displacement curves generated. Testing data for each construct were determined and compared using either a Student's paired t-test (quantitative data) or a χ(2) test (qualitative data) with statistical significance set at P < .05.
RESULTS:
Yield load (elastic limit), ultimate load at failure, and displacements at loads corresponding to walk and trot were determined from each curve. Mean ± SD ultimate load at failure was significantly higher (P = .01) for CCS constructs (1261 ± 261 N) than for CNS constructs (1078 ± 231 N). Yield loads were not significantly different (P = .10) between construct types, and exceeded all expected loads supported by the humeral condyle at walk. The risk of having a yield load below the expected physiologic load at trot was not statistically higher with a CNS construct compared with a CCS construct (P = .26).
CONCLUSION:
Humeral condylar fracture repaired either by a 4.0-mm cannulated screw or a 4.0-mm cancellous screw have comparable stability in this condylar fracture model.