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.

Objective-To compare variables for screw insertion, pushout strength, and failure modes for a headless tapered compression screw inserted in standard and oversize holes in a simulated lateral condylar fracture model. Sample Population-6 pairs of third metacarpal bones from horse cadavers. Procedure-Simulated lateral condylar fractures were created, reduced, and stabilized with a headless tapered compression screw by use of a standard or oversize hole. Torque, work, and time for drilling, tapping, and screw insertion were measured during site preparation and screw implantation. Axial load and displacement were measured during screw pushout. Effects of drill hole size on variables for screw insertion and screw pushout were assessed by use of Wilcoxon tests. Results-Drill time was 59% greater for oversize holes than for standard holes. Variables for tapping (mean maximum torque, total work, positive work, and time) were 42%, 70%, 73%, and 58% less, respectively, for oversize holes, compared with standard holes. Variables for screw pushout testing (mean yield load, failure load, failure displacement, and failure energy) were 40%, 40%, 47%, and 71% less, respectively, for oversize holes, compared with standard holes. Screws could not be completely inserted in 1 standard and 2 oversize holes. Conclusions and Clinical Relevance-Enlarging the diameter of the drill hole facilitated tapping but decreased overall holding strength of screws. Therefore, holes with a standard diameter are recommended for implantation of variable pitch screws whenever possible. During implantation, care should be taken to ensure that screw threads follow tapped bone threads.

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.

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%).

The reports on wing bone fractures are common in avian species, butare scanty with peafowl. An Indian peahen (Pavo cristatus) was presented with a wounded unstable left wing and inability to fly. Crepitus could be felt on palpation and the radiographic examination showed an open, transverse, mid-diaphyseal fracture of humerus. Open reduction, internal fi xation and wound closure were performed under general anaesthesia followed by external coaptation of the operated wing. Post-operative antibiotics and analgesics were administered. Bythird week, clinical signs of healing were noticed and physical therapy was advised.The bird recovered uneventfully and was released. A unique case on management of transverse humerus fracture rarely reported in peafowl is documented.

Whenever bone fractures occur, external forces produce continuous interfragmentary motion and a stabilization method is necessary. It is known that the mechanical conditions at the fracture site influence bone callus formation during healing process. To achieve primary (direct) bone healing, absolute stability at the fracture site is necessary. Perren’s concept of strain determines that relative deformation at the fracture gap depends on the original gap’s conformation. Simple fractures (without comminution) are considered high strain fractures since a small force applied to the fracture site results in great movement with deleterious effects on the healing process. The purpose of this study is to review the available literature regarding factors that influence the mechanics of high strain fractures in veterinary medicine, its treatment methods and implants available. Each fracture configuration requires special attention and critical care in choosing the osteosynthesis method and the type of stability required for consolidation to occur within the expected time. One must know the strain theory to become an orthopedic surgeon.