Acute Failure Characteristics of Six Methods for Internal Fixation of Canine Femoral Oblique Fractures

1996 ◽  
Vol 09 (03) ◽  
pp. 106-10 ◽  
Author(s):  
E. Egger ◽  
J. Huhta ◽  
M. Histand ◽  
C. Mallinckrodt ◽  
R. Nye
Keyword(s):  
Internal Fixation ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Testing Machine ◽  
Maximum Load ◽  
Dynamic Compression Plate ◽  
Fixation Methods ◽  
Compression Plate

SummaryA long oblique osteotomy model of canine femoral fractures was created to compare six methods of internal fixation. The following methods were tested: three cerclage wires, three lag screws, eight-hole dynamic compression plate attached with six cerclage wires, eight-hole dynamic compression plate attached with six cortical screws, eight-hole dynamic compression plate attached with six cortical screws superimposed over three cerclage wires, and an eight-hole dynamic compression plate attached with six cortical screws superimposed over three lag screws. The repaired femurs were mounted in a mechanical testing machine in an orientation designed to mimic physiological loading. Axial compression was applied which resulted in the test specimens experiencing simultaneous compressive and bending forces. The effects of the method of osteotomy repair, bone temperature, and bone diameter were analyzed. The maximum load and the stiffness of the composite fixation and bones were determined. There were not any statistically significant differences in stiffness among the groups. All fixation methods, in which plates were attached with screws, resulted in significantly greater maximum load values than treatment techniques where plates were not used. None of the fixation methods attained a mean maximum load greater than 58% of the mean maximum load of the control femurs.Six methods of commonly used internal fixation methods are compared. A method of in vitro positioning of test femurs to mimic in vivo orientation is presented. Maximum load capabilities of fixation do not significantly increase with the addition of interfragmentary compression to plate fixation.

In vitro mechanical evaluation of a limited contact dynamic compression plate and hybrid carpal arthrodesis plate for canine pancarpal arthrodesis

2012 ◽  
Vol 25 (02) ◽  
pp. 83-88 ◽  
Author(s):  
R. P. Guillou ◽  
R. M. Demianiuk ◽  
M. T. Sinnott ◽  
K. Curcio ◽  
C. E. DeCamp ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Dynamic Compression ◽  
Testing Machine ◽  
Hydraulic Testing ◽  
Dynamic Compression Plate ◽  
Compression Plate ◽  
Hybrid Plate ◽  
Post Hoc ◽  
Supporting Structures

SummaryObjective: To compare the mechanical properties of pancarpal arthrodesis (PCA) constructs stabilized at 20° of extension using either a 3.5 mm limited contact dynamic compression plate (LC-DCP) or a 3.5/2.7 mm hybrid plate (HP).Methods: Seven forelimb pairs were used from dogs of similar size. All soft tissues were removed except for supporting structures of the carpus and proximal metacarpal region. All plates were accurately bent to 20°, and then instrumented with two, 350Ω strain gauges applied at the level of the bend. Constructs were embedded in epoxy moulds then mounted onto a servo-hydraulic testing machine. Specimens were loaded for 10 cycles at 100N, 200N and 300N. Tenth cycle construct compliance (CC), maximum angular deformation (MAD), and peak plate strain (PPS) were compared using two-factor analysis of variance (ANOVA) and Student-Newman- Keuls post-hoc tests (p <0.05).Results: Regardless of load, CC was 29% to 33% smaller in the HP than the LC-DCP group (p <0.03). In each group, the CC significantly increased with increasing loads (p <0.02). Mean MAD was 19% to 22% less in HP than LC-DCP constructs, with significant differences seen at 200N and 300N loads. In both groups, MAD was significantly greater with increasing loads (p <0.02). In addition, PPS was 37% to 43% smaller for HP than LC-DCP.Clinical significance: The mechanical advantages of the HP over the LC-DCP make it a viable alternative for PCA. Smaller CC, MAD and PSS of the HP may reduce the risk of implant failure and postoperative morbidity following PCA.

scholarly journals A biomechanical comparison of 3.5 locking compression plate fixation to 3.5 limited contact dynamic compression plate fixation in a canine cadaveric distal humeral metaphyseal gap model

2009 ◽  
Vol 22 (04) ◽  
pp. 1-8 ◽  
Author(s):  
O. Lanz ◽  
R. McLaughlin ◽  
S. Elder ◽  
S. Werre ◽  
D. Filipowicz
Keyword(s):  
Axial Compression ◽  
Dynamic Testing ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Locking Compression Plate ◽  
Locking Plates ◽  
Gap Model ◽  
Static Compression ◽  
Dynamic Compression Plate ◽  
Compression Plate

Summary3.5 locking compression plate (LCP) fixation was compared to 3.5 limited contact dynamic compression plate (LC-DCP) fixation in a canine cadaveric, distal humeral metaphyseal gap model. Thirty paired humeri from adult, large breed dogs were separated into equal groups based on testing: static compression, cyclic compression, and cyclic torsion. Humeral constructs stabilized with LCP were significantly stiffer than those plated with LCDCP when loaded in static axial compression (P = 0.0004). When cyclically loaded in axial compression, the LCP constructs were significantly less stiff than the LC-DCP constructs (P = 0.0029). Constructs plated with LCP were significantly less resistant to torsion over 500 cycles than those plated with LC-DCP (P<0.0001). The increased stiffness of LCP constructs in monotonic loading compared to constructs stabilised with non-locking plates may be attributed to the stability afforded by the plate-screw interface of locking plates. The LCP constructs demonstrated less stiffness in dynamic testing in this model, likely due to plate-bone offset secondary to non-anatomic contouring and occasional incomplete seating of the locking screws when using the torque-limiting screw driver. Resolution of these aspects of LCP application may help improve the stiffness of fixation in fractures modeled by the experimental set-up of this investigation.

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