In this case report, the clinical and radiographic results of the treatment of Salter Harris Type II fracture in the left humerus of a 10-month-old female and crossbred dog with parallel pin technique was evaluated. The dog with complaining of lameness was brought to Siirt University, Faculty of Veterinary Medicine, Clinic of Surgery Department and local fracture findings were found in the distal 1/3 of the left humerus. On radiological examination, it was found that the distal physeal line of the left humerus was detached. Also, it was seen that the integrity of the bone cortex was disrupted through in a line that included the metaphysis at the medial angle. In the operation, following the reduction of the fracture fragments, 2 krischner pins with 2 mm in diameter parallel to each other were applied from the medial cortex of the humerus to the lateral side of the distal condule and fixation was achieved. After the operation, the limb was taken to a backed bandage. In the radiological examination of the case on post-op 3rd week, it was found that the formation of the collus began. On the post-op 21st day, the bandage was removed and physical therapy applications were started to apply. On the post-op 4th week, it was seen that the dog used the extremity functionally and it was discharged. As a result, it was concluded that parallel double pin applications can be used successfully in the treatment of Salter Harris Type II fractures that are formed in the distal of dog's humerus.

Objective: To compare the axial stiffness, maximum axial displacement, and ring deformation during axial loading of single complete and incomplete circular (ring) external skeletal fixator constructs. Sample: 32 groups of single ring constructs (5 constructs/group). Procedures: Single ring constructs assembled with 2 divergent 1.6-mm-diameter Kirschner wires were used to stabilize a 60-mm-long segment of 16-mm-diameter acetyl resin rod. Construct variables included ring type (complete or incomplete), ring diameter (50, 66, 84, or 118 mm), and fixation wire tension (0, 30, 60, or 90 kg). Axial loading was performed with a materials testing system. Construct secant stiffness and maximum displacement were calculated from the load-displacement curves generated for each construct. Ring deformation was calculated by comparing ring diameter during and after construct loading to ring diameter prior to testing. Results: Complete ring constructs had greater axial stiffness than did the 66-, 84-, and 118-mm-diameter incomplete ring constructs. As fixation wire tension increased, construct stiffness increased in the 66-, 84-, and 118-mm-diameter incomplete ring constructs. Maximum axial displacement decreased with increasing fixation wire tension, and complete ring constructs allowed less displacement than did incomplete ring constructs. Incomplete rings were deformed by wire tensioning and construct loading. Conclusions and Clinical Relevance: Mechanical performance of the 66-, 84-, and 118-mm-diameter incomplete ring constructs improved when wire tension was applied, but these constructs were not as stiff as and allowed greater displacement than did complete ring constructs of comparable diameter. For clinical practice, tensioning the wires placed on 84- and 118-mm-diameter incomplete rings to 60 kg is recommended.

By use of wire ropes as the transosseous component, an external skeletal fixator for the repair of long bone fractures in horses and cattle has been designed and tested in axial compression. Theoretical methods were used in the design process to size fixator components; however, our results suggest that conventional methods of analyzing the displacement of the transosseous component may not apply to wire ropes. Large pretensions in the wire ropes are necessary to obtain functional stiffnesses for fracture fixation. Therefore, a method was sought for terminating the ropes so that an appropriate pretension could be introduced into the rope through its interface with the fixator rings. Ropes were terminated by use of 5 methods and were tested in axial tension to failure. These methods included 3 copper sleeve arrangements, welded ends, and drum sockets. The drum sockets (57.6% of rope breaking strength) far exceeded the strengths provided by the copper sleeves (8.5 to 26.6%) and the welded ends (44.3%). Using the drum sockets, 5 rope configurations were assembled to the fixator, using wood blocks to simulate bones with a gap defect. The fixator was loaded in axial compression for each of the rope configurations, and stiffnesses were determined from measured axial displacement and applied load. The 4-ring fixator configuration, with 2 ropes at 60 degrees angular separation/ring, was the stiffest. In a worst case (gap) model, a mean axial compression load of 1,730 N was observed at 2 mm of displacement for a 4-ring fixator configuration. Our results suggest that, in less conservative scenarios where compression of the fracture surfaces can share limb loads, wire ropes may function well as the transosseous components of an external fixator.

The effect of 5 fracture fixation methods on bone mineral density (BMD) measurement of femurs, using dual-energy X-ray absorptiometry (DXA) was determined in a canine model. Six regions of interest were measured, including the entire femur, the diaphysis of the femur, and small regions centered over the middiaphysis of the bone (lateral middiaphyseal cortex, medial middiaphyseal cortex, middiaphyseal medullary canal, and total middiaphysis). Eight unpaired femurs were collected and scanned by use of DXA before (5 separate scans/femur) and after (5 separate scans/femur) fixation by use of 1 of 5 fixation methods. These fixation methods included: intramedullary (IM) nail: IM nail and cerclage wires; IM nail and external skeletal fixation.; locked IM nail; and a dynamic compression plate (DCP). All implants were made of stainless steel. The IM nail fixation devices caused significant decreases in the DXA measurement of BMD in the small regions of interest, compared with femurs without fixation devices (mean decrease, 37.3%; P < 0.05). The locked nail caused similar, but larger, decreases in the DXA measurement of BMD, compared with the IM nail fixation methods (P < 0.05). Plate fixation caused a small, but significant (P < 0.05), decrease (2.8%) in the DXA measurement of BMD in the large regions of interest, but when all regions were averaged, it did not cause significant change in this measurement, compared with femurs without fixation devices. Plate fixation caused a large change in the DXA measurement of BMD in 1 region only in the lateral cortical bone under the plate where the DXA measurement of BMD was increased 13.3% over that in femurs without fixation devices (P < 0.05). In femurs without fixation devices, the precision error ranged from 0.5% for large regions of interest to 2.4% for small regions of interest. None of the fixation methods altered the precision error of large regions of interest (P > 0.05). In contrast, the precision errors of the small regions of interest were increased by the IM fixation methods and the locked IM nail, When all regions were combined, IM fixation methods caused significant (P < 0.05) increase in the precision error, compared with femurs without fixation devices (mean increase, 157%; range, 121 to 193%). Plate fixation did not change the precision error of any region of interest, compared with femurs without fixation devices (P > 0.05; power = 0.8 at delta = 64%).

Holding power was determined for various orthopedic screws in bones of calves. Holding power was defined as maximal tensile force required to remove a screw divided by thickness of bone engaged by the screw (kN/mm). Comparative pull-out tests were performed, using pairs of large metacarpal or metatarsal bones from calves aged 3 to 14 days. Comparisons were made of the holding power of 6.5-mm fully threaded cancellous screws and 5.5-mm cortical screws in the proximal and distal metaphyses, and of 4.5-mm and 5.5-mm cortical screws in the diaphysis. Sixteen repetitions of each comparative trial were performed. There was no statistically significant difference in the holding power of 4.5- and 5.5-mm cortical screws in the diaphysis. There was no significant difference in the holding power of 5.5-mm cortical and 6.5-mm fully threaded cancellous screws in the proximal metaphysis. In the distal metaphysis, 6.5-nu-n fully threaded cancellous screws had significantly (P < 0.001) greater holding power than did 5.5-mm cortical screws. There was no significant difference between the mean holding power of 5.5-mm cortical screws in the proximal metaphysis and 5.5-mm cortical screws in the distal metaphysis. There was significantly (P < 0.01) greater mean holding power of 6.5-mm cortical, fully threaded cancellous screws in the distal metaphysis, compared with the proximal metaphysis.

OBJECTIVE To compare the torsional mechanical properties of 2 external skeletal fixators (ESFs) placed with 2 intramedullary pin (IP) and transfixation pin (TP) size combinations in a model of raptor tibiotarsal bone fracture. SAMPLE 24 ESF-synthetic tibiotarsal bone model (polyoxymethylene) constructs. PROCEDURES Synthetic bone models were fabricated with an 8-mm (simulated fracture) gap. Four types of ESF-synthetic bone model constructs (6/group) were tested: a FESSA with a 1.6-mm IP and 1.6-mm TPs, a FESSA with a 2.0-mm IP and 1.1-mm TPs, an acrylic connecting bar with a 1.6-mm IP and 1.6-mm TPs, and an acrylic connecting bar with a 2.0-mm IP and 1.1-mm TPs. Models were rotated in torsion (5°/s) to failure or the machine angle limit (80°). Mechanical variables at yield and at failure were determined from load deformation curves. Effects of overall construct type, connecting bar type, and IP and TP size combination on mechanical properties were assessed with mixed-model ANOVAs. RESULTS Both FESSA constructs had significantly greater median stiffness and median torque at yield than both acrylic bar constructs; FESSA constructs with a 1.6-mm IP and 1.6-mm TPs had greatest stiffness of all tested constructs and lowest gap strain at yield. No FESSA constructs failed during testing; 7 of 12 acrylic bar constructs failed by fracture of the connecting bar at the interface with a TP. CONCLUSIONS AND CLINICAL RELEVANCE Although acrylic bar ESFs have been successfully used in avian patients, the FESSA constructs in this study were mechanically superior to acrylic bar constructs, with greatest benefit resulting from use with the larger TP configuration.

In this case report, treatment of the proximal tibial fracture of a calf with a linear external fixator (orthofix) system was presented. Oblique fracture was diagnosed proximal to left tibia regarding the clinical and radiological findings. Following the routine preparatory steps for the operation, the extremity was suspended and the fracture was reduced with orthofix from the lateral side of the tibia under general anesthesia. After the operation, it was observed that the calf could functionally use the related extremity from the first day. The consolidation was completed on the 41st day, and the fixator was removed on 47th day. In conclusion, it was considered that the proximal tibial fractures of calves could be successfully treated with a linear external fixator.

Objective-To describe a novel interlocking nail (ILN) and locking system and compare the torsional properties of constructs implanted with the novel ILN or a standard 8-mm ILN (ILN8) by use of a gap-fracture model. Sample Population-8 synthetic specimens modeled from canine tibiae. Procedures-An hourglass-shaped ILN featuring a tapered locking mechanism was designed. A synthetic bone model was custom-made to represent canine tibiae with a 50-mm comminuted diaphyseal fracture. Specimens were repaired by use of a novel ILN or an ILN8 with screws. Specimens were loaded for torsional measurements. Construct compliance and angular deformation were compared. Results-Compliance of the ILN8 was significantly smaller than that of the novel ILN. Mean +/- SD maximum angular deformation of the ILN8 construct (23.12 +/- 0.65 degrees) was significantly greater, compared with that of the novel ILN construct (9.45 +/- 0.22 degrees). Mean construct slack for the ILN8 group was 15.15 +/- 0.63 degrees, whereas no slack was detected for the novel ILN construct. Mean angular deformation for the ILN8 construct once slack was overcome was significantly less, compared with that of the novel ILN construct. Conclusions and Clinical Relevance-Analysis of results of this study suggests that engineering of the locking mechanism enabled the novel hourglass-shaped ILN system to eliminate torsional instability associated with the use of current ILNs. Considering the potential deleterious effect of torsional deformation on bone healing, the novel ILN may represent a biomechanically more effective fixation method, compared with current ILNs, for the treatment of comminuted diaphyseal fractures.

Axial stability of equine oblique proxidmal phalangeal osteotonies with application of the standard short limb cast or 1 of 3 configurations of transfixation casts was determined in vitro. Transfixation cast methods included use of parallel pins, divergent pins, or parallel pins incorporating a metal walking bar. Displacement at the osteotomy was recorded for each limb at 4,448 N. Standard short limb casts provided significantly (P = 0.0002) less axial stability than did any form of transfixation cast. Significant differences were not found between the 3 transfixation casts.

Breaking strength (torque at failure) of equine third metacarpal bones, with transfixation pins placed parallel in the frontal plane and 30 degrees divergent from the frontal plane, was determined in vitro. Two transfixation pins were placed through the distal metaphysis, using a jig designed to drill the holes in the assigned configuration. Paired metacarpal bones II through IV from 12 horses were tested in torsion. The torsional moment of the force applied through the transfixation pins at failure was compared for each limb. Metacarpal bones with divergent pins were significantly (P = 0.030) stronger, compared with those with parallel pins. Metacarpal bones with parallel pins failed with longitudinal oblique fractures through a proxidmal bone-pin interface, whereas those with divergent pins failed with more comminuted fractures through multiple bone-pin interfaces.