Bone fractures in dogs: A retrospective study of 129 dogs

The aim of the present study was to evaluate 129 dogs with different breed, age and sex admitted to the clinic of Department of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Zagazig University over a 2-year period with different kinds of fractures. Thorough clinical and radiographic examinations were performed to all animals. The results revealed that German shepherd dogs (74.41%), immature dogs below 1 year of age (80.62%) and male dogs (57.36%) were the most susceptible to fractures. The percentages of fractures of the hind limb (48.06%) were the most common location of the fractures on animals followed by forelimb fractures (28.68%) then pelvic fractures (20.16%) and fractures of the mandible (3.1%). Femur fractures (27.13%) were the most common long bone fractures followed by tibia/fibula (15.5%) then radius/ulna (11.63%) and humerus (10.08%). About 79.84% of animals were treated by gypsona (42.72%), cross pins (22.33%), plate and screws (18.45%), intramedullary pins (14.56%) and wiring (1.94%). Satisfactory results were reported in 86.40% of treated animals and post-operative complications were reported in 13.60% of animals. It was concluded that immature and male dogs were more susceptible to bone fractures. Most of fixation methods are successful when basic principles of fracture repair are followed.

Over the last 10 years, pet care has been progressed dramatically in our population. Despite of more care of owners with their pet animals, they are susceptible to many accidental disorders especially orthopedic disorders. In pet animals, bone fractures represent the most common major problem particularly in dogs (1). Long bone fractures particularly femur constitute the most common injury in dogs and cats (2). The most common cause of fractures in pet animals are violent trauma with fallen down from height or vehicular accident (3)(4)(5). Evaluation of the fracture is the most important point in fracture treatment. It should be assessed for location, type, involvement of the joint, fragment direction and number and whether open or closed (3).
Restoration of the normal structure and function of the fractured part is the main goal of treatment. Fixation method should neutralize the intrinsic and extrinsic forces generated on the fractured part to be restored in normal structural phase (3,(6)(7)(8)(9)(10). Various fixation methods used to manage fractures of dogs including external cooptation, intramedullary (IM) pins, bone plates and screws, external skeletal fixation (ESF), interlocking nail (ILN) and lag screw (11,12). Many factors control the selection of proper fixation method such as animal age and size, number of involved limbs, type of fracture, location of fracture, soft tissue injuries, surgeon capabilities and facilities (8). Therefore, the aim of this study was to evaluate 129 dogs with different breed, age and sex admitted to our clinic over a 2-year period with different kinds of fractures.

Materials and methods
A total of 129 dogs were admitted to the clinic of Department of Surgery, Anesthesiology and Radiology-Faculty of Veterinary Medicine-Zagazig University over a 2-year period with a history of limb or mandible fractures. Vertebral fractures or neurogenic disorders were not investigated. Breed, age, sex of animals was recorded.
The animals were clinically examined by inspection to assess animal ' s gait, pasture and cardinal signs of inflammation, then by local manipulation to detect pain, abnormal motion and crepitus at the affected site. Two diagonal radiographs were taken for each animal at the affected site using X-ray machine (Pox-300 BT, Toshiba, Rotanode TM , Japan) with appropriate exposure factors based on the weight and depth of the affected animal and then interpreted for treatment decision.
Different treatment techniques including Plaster of Paris, bone plate and screws, IM pins, cross pins and stainless-steel wire were performed according to type and location of the fracture and owner acceptance. Post-operative prognosis of the treated animals was reported either through bringing of the animals to the clinic when possible or by calling the owners.

Discussion
Bone fractures in the present study were most commonly in German shepherd dogs (74.41%) followed by Doberman pinscher (19.38%), then White Griffon (2.33%), Rottweiler (2.33%) and non-descriptive dogs (1.55%). This might be due to more interest of our population to keep this dog breed. Immature dogs below one year of age (80.62%) were more susceptible to fractures; might be due to the fragility of their bones in comparison to older ones (13)(14)(15). These findings were in agreement with previously described by Aithal et al; Minar et al; Kolata et al. (11,16,17).
Fractures were more common in male dogs than females that might be attributed to aggressive nature, wandering habits and the high metabolic rate of males. These results were in line with previously reported Aithal et al.; Simon et al.; Kolata et al. (11,15,17). Violent trauma due to fall down from height and vehicle accident were the common causes of fractures as reported previously (2,18). This might be due to most people in our population keep their own dogs on the roof of the buildings and others for playing and jumping. These findings were in contrast with those reported previously Minar et al; Phillips; Bennour et al. (16,19,20) where they reported that the most common cause of fracture was traffic accident followed by fall down.
Long bone fractures including humerus, radius/ulna, femur and tibia/fibula were the most common orthopedic problem in growing dogs (15,19,21,22). Our results were in agreement with these findings where the long bone fractures represented about 64.33% from total fractures. Pelvic fractures accounted approximately 20.16% of all fractures. It was reported that pelvic fractures accounted approximately 25% of all fractures in dogs (16,23,24). Fractures of the hind limb were more commonly reported than forelimb as previously reported Minar et al. (16).  (10,11,13,25) followed by tibia/fibula (15.5%), then radius/ulna (11.63%)and humerus (10.08%). These findings were similar to previously reported Harasen; Aithal et al. (11,16). Middle fractures were the most common long bone fractures (44.58%), followed by distal fractures (37.35%), then proximal fractures (18.07%). These results were in contrast with these reported previously Minar et al. (16) where they reported that distal fractures represented 67% of long bone fractures followed by middle then proximal fractures.
Proper reduction of fractured bone with normal alignment and using proper fixation method were important for good prognosis (25). Most of animals (79.84%) were treated with different fixation methods including Plaster of Paris (42.72%), followed by cross pins (22.33%), then plate and screws (18.45%), IM pins (14.56%) and wiring (1.94%). The aim of fracture fixation is to provide adequate fracture stability with significant reduction in local strain at the fracture area (26). The prognosis of the treated animals was satisfactory in 86.40% and post-operative complications were reported in 13.60% of the treated animals including pin migration (4.86%), followed by malunion (3.89%), then osteomyelitis (2.91%), bone refracture (0.97%) and muscle atrophy (0.97%).
The findings of the present study revealed that immature and male dogs were more susceptible to bone fractures. Most of fixation methods are successful when basic principles of fracture repair are followed. Many fixation methods including Plaster of Paris, IM pins, bone plates and screws, cross pins and wiring were used according to location and type of the fracture, age and size of the animals.