BACKGROUND: Femoral head osteotomy in cases of fractures or degenerative diseases is as a routine surgical procedure. Less duration of the healing period and the creation of minimal fibrous tissue and its replacement with bone tissue can be effective in return to health. OBJECTIVES: The aim of this study was to evaluate the histopathological changes following administration of platelet-rich plasma at the site of  removed femoral head in rabbits. METHODS: Twenty male New Zealand white rabbits were distributed into two groups including: control (underwent femoral head osteotomy, FHO) and treatment (underwent FHO and planting the platelet-rich plasma on surgical site FHO₊ PRP). In both groups after general anesthesia, femoral head was removed using standard method. In group 2, pre-prepared auto log PRP was used at the site of surgery. After eight weeks all animals were euthanised, femur and its  surrounding healing tissues were cut 2cm  far from the head of femur and removed. Slides were prepared from each sample  through serial sectioning and were stained with H&E and Mason Trichrome. Qualitative changes such as granulation tissues, cartilage and bone formation and their organization and timeliness, thickness of collagen fibers and cellular changes were compared. To quantify the changes, whole surface of the Mason Trichrom stained samples underwent scan with ×50 magnifications and then area of different new formation tissues was measured. Average occupancy levels of each tissue, their ratio to whole surface of sample and to each other in two groups were calculated and compared. RESULTS: In PRP treated group ratio of cartilage tissue to granulation tissue and formation of bone to granulation tissue is significantly more than these parameters in control group. Results indicate faster healing on the damaged area in group 2. Also in group 2, cartilage and bone tissues formation in the healing process was more orderly. CONCLUSIONS: PRP could accelerate healing of bone tissue that is cut at the head of the rabbit’s femur. So it seems that the use of PRP as a treatment protocol in these cases could be suggested.

In recent years, the use of bone scaffolds as bone tissue substitutes, especially the use of such as hydroxyapatite and tricalcium phosphate, has been very popular. Today, the use of modern engineering techniques and advances in nanotechnology have expanded the use of nanomaterials as bone scaffolds for bone tissue applications. This study was performed on 60 adult male New Zealand rabbits divided into four experimental groups: the control group without any treatment, the second group receiving hydroxyapatite, the third group treated with β-tricalcium phosphate, and the fourth group receiving nanocomposite polycaprolactone (PCL) scaffold. In a surgical procedure, a defect 6 mm in diameter was made in a hind limb femur. Four indexes were used to assess histopathology, which were union index, spongiosa index, cortex index, and bone marrow. The results showed that nanocomposite PCL and control groups always had the respective highest and lowest values among all the groups at all time intervals. The histopathological assessment demonstrated that the quantity of newly formed lamellar bone in the nanocomposite PCL group was higher than in other groups. All these data suggest that PCL had positive effects on the bone healing process, which could have great potential in tissue engineering and clinical applications.

Due to the widespread occurrence of acrylamide in the environment, its likely carcinogen status, and the suitability of the pig model as a human analogue, the authors decided to evaluate the impact of high and low doses of this compound on the processes of erythropoiesis in swine bone marrow. The experiment was carried out on Danish Landrace pigs at the age of eight weeks and body weight about 20 kg. The animals were divided into three equal groups consisting of five pigs in each. Control animals received empty gelatin capsules (placebos). Animals from the first experimental group received a low dose of acrylamide of 0.5 μg/kg b.w./day (> 99% purity; Sigma-Aldrich, Poland), and animals from the second experimental group received a dose 10 times higher. Placebos and acrylamide capsules were administered with feed every morning for 28 days. After anaesthetisation of the animals, bone marrow from the femur was collected into tubes without an anticoagulant on days 0 and 28. After drying and staining, bone marrow smears were subjected to detailed cytological evaluation using a light microscope. This study showed that high and low doses of acrylamide affected the process of porcine erythropoiesis. The cytotoxic effect of acrylamide on this process was demonstrated in a change of the polychromatic erythroblasts/normochromatic erythroblasts ratio. Both doses of acrylamide caused a decrease in the number of ortho- and polychromatic erythroblasts.

Introduction: The aim of the study was to investigate the mechanical and geometric properties as well as bone tissue and mineral density of long bones in mink dams exposed to deoxynivalenol (DON) since one day after mating, throughout gestation (ca. 46 d) and lactation to pelt harvesting. Material and Methods: Thirty clinically healthy multiparous minks (Neovison vison) of the standard dark brown type were used. After the mating, the minks were randomly assigned into two equal groups: nontreated control group and DON group fed wheat contaminated naturally with DON at a concentration of 1.1 mg·kg⁻¹ of feed. Results: The final body weight and weight and length of the femur did not differ between the groups. However, DON contamination decreased mechanical endurance of the femur. Furthermore, DON reduced the mean relative wall thickness and vertical wall thickness of the femur, while vertical cortical index, midshaft volume, and cross-sectional moment of inertia increased. Finally, DON contamination did not alter bone tissue density, bone mineral density, or bone mineral content, but decreased the values of all investigated structural and material properties. Conclusion: DON at applied concentration probably intensified the process of endosteal resorption, which was the main reason for bone wall thinning and the weakening of the whole bone.

As a result of many traumatic factors such as traffic accidents, falls from height, gunshot wounds and animal fights with each other, orthopedic and soft tissue damage, especially fractures, occur in the musculoskeletal system. Among the fractures within these lesions, the incidence of hind limb long bone fractures is higher than other bones. While the incidence of femur fractures among other fractures in cats is 20-26%, tibia fractures constitute a significant proportion of approximately 20% of other fractures. This study aimed to retrospectively evaluate the distribution, etiology, treatment, and treatment results of fractures in cats with hind limb bone fractures (n=92). In addition to the use of intramedullary nails and plates, external fixators are also used for the treatment of hind limb bone fractures. Despite the advantages and disadvantages of each technique, most of the time no problems are observed during the application of these techniques and in the postoperative period. A functional recovery was observed in all cats at postoperative follow-up. As a result, it can be said that the method to be used in hind limb bone fractures in cats varies according to the surgeon's preference, experience, and existing orthopedic material inventory. However, anatomical locking plates have the advantages of not using postoperative bandages and allowing the limb to be used early.

The aim of this study was to present 6 dogs and 2 cats treated with handmade external fixator. The animals included in the study had 3 cases of non-union, 1 case of luxation, and 4 cases of fracture. All the cases were successfully treated with a handmade external fixator which was made from an endotracheal tube and epoxy. There were no complications developed except for light leakage in the pin site in one case. All of the animals had started to use their extremities in the early postoperative period, except for one case. As the fixator provided the opportunity for weight-bearing, increasing stability in the fracture line in the early postoperative period, this provided some beneficial effects on healing. The external fixator made using an endotracheal tube and epoxy can be selected as an inexpensive treatment method for cats and dogs.

Six dogs with unstable diaphyseal fracture of femur of different breeds of either sex and bodyweight ranging from 10 to 30 kg presented to the Small Animal Orthopedic Unit of the Madras Veterinary College Teaching Hospital, over a period of two years underwent fracture fixation with latest technique of linear locking compression plates. Different sizes and length of new generation locking plate system were used for different configuration of unstable fracture of femur. The post operative assessment of fracture healing was evaluated by radiographs at different intervals and estimation of bone specific serum alkaline phosphatase enzyme by fluorimetric methods. In the present study, the locking compression plating technique provided adequate apposition, stable fixation and promoted early weight bearing of traumatized limb. The locking plate system had a unique combi hole design in a single implant and enabled to select the function best suited for the fracture configuration to achieve the most stable fixation. The locking plate system acted as a single beam construct which increased the stiffness of the implant and was found appropriate in management of unstable or comminuted diaphyseal fracture of femur in dogs.

OBJECTIVE To evaluate the 3-D geometry of canine pelves and to characterize the long-term effects of juvenile pubic symphysiodesis (JPS) on pelvic geometry by comparing the pelvic configuration between littermates that did and did not undergo the procedure. ANIMALS 24 Labrador Retriever, Golden Retriever, or Labrador Retriever–Golden Retriever crossbred service dogs from 13 litters. PROCEDURES At 16 weeks old, puppies with a hip joint distraction index ≥ 0.5 were randomly assigned to undergo thermal JPS (n = 9), mechanical JPS (7), or a sham (control) surgical procedure (8). Ten years later, each dog underwent a CT scan of the pelvic region. Modeling software was used to create 3-D reconstructions from the CT scans, and various pelvic measurements were made and compared among the 3 treatments. RESULTS Compared with the control treatment, thermal and mechanical JPS increased the hemipelvis acetabular angle by 4°, the acetabular angle of lateral opening by 5°, and the orientation of the medial acetabular wall in a transverse plane by 6°, which indicated that JPS increased dorsal femoral head coverage by the acetabulum. Both JPS procedures decreased the pelvic canal area by approximately 20% and acetabular inclination by 6° but did not alter acetabular retroversion. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that thermal and mechanical JPS were equally effective in altering the 3-D pelvic geometry of dogs. These findings may help guide future studies of alternatives for optimizing canine pelvic anatomy to minimize the risk of hip dysplasia and associated osteoarthritis.

Objective- To compare accuracy of a noninvasive single-plane fluoroscopic analysis technique with radiostereometric analysis (RSA) for determining 3-D femorotibial poses in a canine cadaver stifle joint treated by tibial-plateau-leveling osteotomy (TPLO). Sample- Left pelvic limb from a 25-kg adult mixed-breed dog. Procedures- A CT scan of the left pelvic limb was performed. The left cranial cruciate ligament was transected, and a TPLO was performed. Radiopaque beads were implanted into the left femur and tibia, and the CT scan was repeated. Orthogonal fluoroscopic images of the left stifle joint were acquired at 5 stifle joint flexion angles ranging from 110° to 150° to simulate a gait cycle; 5 gait cycles were completed. Joint poses were calculated from the biplanar images by use of a digitally modified RSA and were compared with measurements obtained by use of hybrid implant-bone models matched to lateral-view fluoroscopic images. Single-plane measurements were performed by 2 observers and repeated 3 times by the primary observer. Results- Mean absolute differences between results of the single-plane fluoroscopic analysis and modified RSA were 0.34, 1.05, and 0.48 mm for craniocaudal, proximodistal, and mediolateral translations, respectively, and 0.56°, 0.85°, and 1.08° for flexion-extension, abduction-adduction, and internal-external rotations, respectively. Intraobserver and interobserver mean SDs did not exceed 0.59 mm for all translations and 0.93° for all rotations. Conclusions and Clinical Relevance- Results suggested that single-plane fluoroscopic analysis by use of hybrid implant-bone models may be a valid, noninvasive technique for accurately measuring 3-D femorotibial poses in dogs treated with TPLO.

Objective: To develop an orthotopic model of canine osteosarcoma in athymic rats as a model for evaluating the effects of stereotactic radiotherapy (SRT) on osteosarcoma cells. Animals: 26 athymic nude rats. Procedures: 3 experiments were performed. In the first 2 experiments, rats were injected with 1 × 10(6) Abrams canine osteosarcoma cells into the proximal aspect of the tibia (n = 12) or distal aspect of the femur (6). Tumor engraftment and progression were monitored weekly via radiography, luciferase imaging, and measurement of urine pyridinoline concentration for 5 weeks and histologic evaluation after euthanasia. In the third experiment, 8 rats underwent canine osteosarcoma cell injection into the distal aspect of the femur and SRT was administered to the affected area in three 12-Gy fractions delivered on consecutive days (total radiation dose, 36 Gy). Percentage tumor necrosis and urinary pyridinoline concentrations were used to assess local tumor control. The short-term effect of SRT on skin was also evaluated. Results: Tumors developed in 10 of 12 tibial sites and all 14 femoral sites. Administration of SRT to rats with femoral osteosarcoma was feasible and successful. Mean tumor necrosis of 95% was achieved histologically, and minimal adverse skin effects were observed. Conclusions and Clinical Relevance: The orthotopic model of canine osteosarcoma in rats developed in this study was suitable for evaluating the effects of local tumor control and can be used in future studies to evaluate optimization of SRT duration, dose, and fractionation schemes. The model could also allow evaluation of other treatments in combination with SRT, such as chemotherapy or bisphosphonate, radioprotectant, or parathyroid hormone treatment.