Publications by authors named "Jason D Coggeshall"

7 Publications

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Adjunct fixation with a Kirschner wire or a plate for lateral unicondylar humeral fracture stabilization.

Vet Surg 2017 Oct 22;46(7):933-941. Epub 2017 Jun 22.

Comparative Orthopaedic and Biomechanics Laboratory, University of Florida, Gainesville, Florida.

Objective: To compare the biomechanical properties of using an interfragmentary 1.6 mm Kirschner wire or a 2.7 mm reconstruction plate as adjunctive epicondylar stabilization in simulated comminuted lateral unicondylar humeral fractures stabilized with a transcondylar 4.5 mm cortical screw.

Study Design: Cadaveric biomechanical assessment.

Sample Population: Paired humeri harvested from 9 young, skeletally mature dogs.

Methods: Simulated comminuted lateral unicondylar humeral fractures were stabilized with a transcondylar 4.5 mm cortical screw placed in lag fashion. Adjunct fixations consisting of a 1.6 mm Kirschner wire on one side, and a 2.7 mm reconstruction plate on the contralateral side, were tested within paired humeri. Repaired humeri were axially loaded to failure and construct stiffness, yield load, and load to failure were obtained from the load-deformation curves.

Results: Stiffness (mean ± SD: 577 ± 245 vs 310 ± 71 N/mm; P = .01), yield load (mean ± SD: 2389 ± 572 vs 1017 N ± 292; P = .0002), and load at failure (mean ± SD: 3351 ± 358 vs 1693 ± 363 N; P = .009) were greater in constructs incorporating a reconstruction plate rather than a Kirschner wire.

Conclusion: Our results support the recommendation for adjunct fixation of comminuted lateral unicondylar humeral fractures with an epicondylar plate.
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http://dx.doi.org/10.1111/vsu.12677DOI Listing
October 2017

Normal patellofemoral kinematic patterns during daily activities in dogs.

BMC Vet Res 2016 Nov 25;12(1):262. Epub 2016 Nov 25.

Comparative Orthopaedics Biomechanics Laboratory, College of Veterinary Medicine, University of Florida, PO Box 100126, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, USA.

Background: Patellar abnormalities are a common cause of pain and lameness in dogs; however, in vivo the relative motion between the femur and patella in dogs is not well described. The objective of this study was to define normal in vivo sagittal plane patellofemoral kinematics in three axes of motion using non-invasive methods. We hypothesized patellofemoral alignment in the sagittal plane would tightly correlate with the femorotibial flexion angle. Six healthy dogs without orthopedic disease underwent computed tomography (CT) of their hind limbs to create 3-D models of the patella and femur. Normal stifle joint motion was captured via flat-panel imaging while each dog performed a series of routine activities, including sitting, walking, and trotting. The 3-D models of the patella and femur were digitally superimposed over the radiographic images with shape-matching software and the precise movement of the patella relative to the femur was calculated.

Results: As the femorotibial joint flexed, the patellofemoral joint also flexed and the patella moved caudally and distally within the femoral trochlea during each activity. Patellar flexion and distal translation during walk and sit were linearly coupled with the femorotibial flexion angle. Offset was evident while trotting, where patella poses were significantly different between early and late swing phase (p ≤ 0.003). Patellar flexion ranged from 51 to 6° while trotting. The largest flexion angle (92°) occurred during sit. The patella traversed the entire proximodistal length of the femoral trochlea during these daily activities.

Conclusions: Using single-plane flat-panel imaging, we demonstrated normal in vivo patellofemoral kinematics is tightly coupled with femorotibial kinematics; however, trot kinematic patterns did not follow the path defined by walking and stand-to-sit motions. Our normal data can be used in future studies to help define patellofemoral joint kinematics in dogs with stifle abnormalities.
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http://dx.doi.org/10.1186/s12917-016-0889-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123255PMC
November 2016

Mechanics of Supplemental Drop Wire and Half-Pin Fixation Elements in Single Ring Circular External Fixator Constructs.

Vet Surg 2016 May 24;45(4):471-9. Epub 2016 Mar 24.

Comparative Orthopaedics and Biomechanics Laboratory, University of Florida, Gainesville, Florida.

Objective: Evaluate the effects of supplemental fixation elements on the mechanical properties of a single ring circular fixator construct.

Study Design: In vitro mechanical testing.

Sample Population: Five construct configurations (six replicates of each configuration) were used to stabilize a 1.6 cm diameter Delrin rod bone model.

Methods: Constructs were assembled using 66 mm complete rings, 1.6 mm olive wires, and 3.2 mm diameter half-pins. Construct configurations tested were a base single ring construct, constructs with 1 supplemental drop wire or constructs with 1, 2, or 3 supplemental half-pins. Constructs were loaded in axial compression, caudocranial and mediolateral bending, and torsion. Strain was measured in individual fixation elements during axial loading.

Results: A supplemental drop wire or half-pin significantly increased bending and torsional stiffness. The supplemental half-pin increased caudocranial stiffness significantly more than placing a drop wire. Placing a 2nd or 3rd pin afforded significantly greater increases in construct stiffness in all modes of loading, with 3 half-pin constructs having significantly greater axial and caudocranial stiffness than 2 half-pin constructs. Placing a single supplemental pin induced cantilever bending resulting in angular displacement of the Delrin rod during axial loading and high strain in both the fixation wire secured distal to the ring and the pin. Supplemental half-pins incrementally reduced strain in all fixation elements and resulted in linear displacement of the Delrin rod during axial loading.

Conclusion: If using supplemental half-pins as fixation elements, insertion of 2 or 3 pins is preferred over a single pin.
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http://dx.doi.org/10.1111/vsu.12467DOI Listing
May 2016

In-vivo three-dimensional knee kinematics during daily activities in dogs.

J Orthop Res 2015 Nov 20;33(11):1603-10. Epub 2015 May 20.

Comparative Orthopaedics and Biomechanics Laboratory, University of Florida, Gainesville, FL, 32610.

The canine knee is morphologically similar to the human knee and thus dogs have been used in experimental models to study human knee pathology. To date, there is limited data of normal canine 3D knee kinematics during daily activities. The objective of this study was to characterize 3D in-vivo femorotibial kinematics in normal dogs during commonly performed daily activities. Using single-plane fluoroscopy, six normal dogs were imaged performing walk, trot, sit, and stair ascent activities. CT-generated bone models were used for kinematic measurement using a 3D-to-2D model registration technique. Increasing knee flexion angle was typically associated with increasing tibial internal rotation, abduction and anterior translation during all four activities. The precise relationship between flexion angle and these movements varied both within and between activities. Significant differences in axial rotation and coronal angulation were found at the same flexion angle during different phases of the walk and trot. This was also found with anterior tibial translation during the trot only. Normal canine knees accommodate motion in all planes; precise kinematics within this envelope of motion are activity dependent. This data establishes the characteristics of normal 3D femorotibial joint kinematics in dogs that can be used as a comparison for future studies.
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http://dx.doi.org/10.1002/jor.22927DOI Listing
November 2015

Effect of dorsal acetabular rim loss on stability of the zurich cementless total hip acetabular cup in dogs.

Vet Surg 2015 Feb 12;44(2):195-9. Epub 2014 Apr 12.

Affiliated Veterinary Specialists, Maitland, Florida.

Objective: To evaluate magnitude and mode of acute load to failure of the Zurich Cementless acetabular cup prosthesis in cadaveric specimens with and without 50% dorsal acetabular rim loss.

Study Design: In vitro mechanical study.

Sample Population: Cadaveric hemipelves of adult dogs (n = 8).

Methods: Each pair of hemipelves was prepared by dissection of surrounding musculature and implantation of a Zurich Cementless acetabular cup prosthesis. One hemipelvis had the dorsal rim left intact (group 1) and the contralateral hemipelvis had 50% of the dorsal rim excised (group 2). Each hemipelvis underwent acute load to failure with an axial load applied through a prosthetic femoral head. Load at failure was compared between hemipelves with and without dorsal rim loss with a paired t-test; P < .05 was considered significant.

Results: Mean failure load was not significantly different between group 1 (3,713 ± 362 N) and group 2 (3,640 ± 751 N; P = .8). Bone fracture (n = 6), ventroversion of the cup (1), and absolute failure unreached at 6,000 N (1) occurred in group 1 and bone fracture (6), ventroversion of cup (1), and cup loosening (1) occurred in group 2.

Conclusions: Zurich Cementless acetabular cup stability does not appear to be compromised by 50% acetabular rim loss at normal physiologic weight bearing loads. Thus, for this system, modifying procedures such as augmentation of the dorsal acetabular rim or deeper reaming for acetabular bed preparation may not be necessary with up to 50% dorsal rim loss with the Zurich Cementless acetabular cup.
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http://dx.doi.org/10.1111/j.1532-950X.2014.12191.xDOI Listing
February 2015

Biomechanical comparison of two implants for the stabilization of incomplete ossification of the humeral condyle lesions in dogs.

Vet Surg 2014 Jan;43(1):58-65

Objective: To compare biomechanical properties of (1) 4.5 mm cortical screws and Fitz Fenestrated Tubular Transcondylar (F2T2) screws; (2) normal humeri and humeri with an intracondylar osteotomy; and (3) humeri with an intracondylar osteotomy stabilized with either a 4.5 mm cortical screw or a F2T2 screw.

Study Design: Cadaveric biomechanical assessment.

Sample Population: 4.5 mm cortical screws (n = 10), 5.85 mm F2T2 screws (n = 10), and paired dog humeri (n = 40).

Methods: Cortical and F2T2 screws were loaded to failure in 3-point bending. Ten pairs of humeri with or without an intracondylar osteotomy were axially loaded to failure. Ten additional pairs of humeri with an intracondylar osteotomy were alternately stabilized with a positional cortical or F2T2 screw and axially loaded to failure.

Results: Mean stiffness, yield load, and failure load was significantly greater (P < .001) for the F2T2 screws compared with cortical screws as well as for intact humeri compared with humeri with an intracondylar osteotomy (P < .001). There were no significant differences in mean stiffness (P = .59), yield load (P = .31), or failure load (P = .24) between humeri with stabilized intracondylar osteotomy.

Conclusion: Isolated F2T2 screws have superior mechanical properties to 4.5 mm cortical screws when loaded in 3-point bending. Intracondylar osteotomy adversely affected humeral mechanical integrity. Osteotomized humeri stabilized by either screw had comparable mechanical properties.
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http://dx.doi.org/10.1111/j.1532-950x.2013.12077.xDOI Listing
January 2014

Primary ovarian teratoma and GCT with intra-abdominal metastasis in a dog.

J Am Anim Hosp Assoc 2012 Nov-Dec;48(6):424-8. Epub 2012 Oct 1.

Dallas Veterinary Surgical Center, Grapevine, TX, USA.

This report describes the simultaneous occurrence of an ovarian teratoma and a granulosa cell tumor (GCT) with intra-abdominal metastasis in a 1.5 yr old female Doberman pinscher. At surgery, a 20 cm, smooth, intact mass associated with the left ovary and multiple 1-2 cm irregular masses in the broad ligament were found. The masses were surgically removed and submitted for histopathology. A histologic diagnosis of a teratoma and a GCT with broad ligament metastasis was made. Further treatment was elected by the owner and included two cycles of carboplatin therapy. The dog was euthanized 6 wk postoperatively for signs related to metastasis and dyspnea. Teratoma of the ovary, although it contains derivatives of all three embryonic germ cell layers, rarely presents together with either ovarian epithelial or sex cord-stromal tumors. To the authors' knowledge, this is the first reported case of an ovarian teratoma coexisting with a primary GCT with intra-abdominal metastasis in the same ovary in a dog.
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http://dx.doi.org/10.5326/JAAHA-MS-5809DOI Listing
January 2013