Mechanical Testing of the New Cage for Tibial Tuberosity Advancement with the Cranial Implant Fixation (TTA CF) Technique-Ex Vivo Study on Sheep Model.

Background: Modifications of tibial tuberosity advancement are well accepted for cranial cruciate rupture repair. We compared the loads that were needed to pull the TTA CF cage out in the two groups. The first group consisted of five sheep in which osteotomy and TTA CF cage fixation were performed as assumed preoperatively. The second group consisted of five sheep in which intraoperative or postoperative discrepancies from preoperative planning were found. This is also the first report describing biomechanical testing after tibial tuberosity advancement with cranial implant fixation (TTA CF) surgical procedures. Results: A total of 10 ovine proximal tibiae were tested biomechanically by tearing out TTA CF implants from the bone. The mean maximal loaded forces to pull out the cage in Group 1, in which fixation of the implant was performed as assumed preoperatively, was 878 ± 61 N, and in Group 2, in which discrepancies from preoperative planning were found, was 330 ± 55 N. The mean implant displacement under maximal load to failure was 2.6 mm and 2.2 mm in Groups 1 and 2, respectively. There was a significant difference between Group 1 and Group 2 in the maximal loads-to-failure; however, the difference in the displacement at maximal loaded forces to pull out the cage was not significant between the groups. Conclusions: The mean maximal loaded forces to pull out the cage was significantly lower in Group 2, where discrepancies from preoperative planning were found (878 ± 61 N vs. 330 ± 55 N). The lower forces that were needed to extract the TTA CF implant from the tibia can lead to the conclusion that biointegration of the implant is also weaker. Correct positioning of the osteotomy line and TTA CF implant is essential for good biointegrity and thus for limiting complications in the form of tibial tuberosity avulsion fracture or tibial shaft fracture.

Assessment of the Usefulness of Image Reconstruction in the Oblique and Double-oblique Sagittal Planes for Magnetic Resonance Imaging of the Canine Cranial Cruciate Ligament.

INTRODUCTION: The aim of the study was to determine the quality and significance of the magnetic resonance image of the canine knee after reconstruction in the oblique and double-oblique sagittal plane. This reconstruction and 3D images are rarely used in common protocols due to the longer study time they require. The study aimed to demonstrate significance for such diagnostic images in specific sequences in order to stimulate consideration of their more frequent use in diagnosis of diseases of the cruciate ligament in dogs. MATERIAL AND METHODS: All tests were carried out using an open magnetic resonance tomography scanner with magnetic field induction. The images obtained from the 30 canine patients examined were reconstructed and evaluated by independent appraisers. Statistical analysis was performed. RESULTS: The study showed that MRI of the stifle joint using 3D sequences provides higher quality images of the cranial cruciate ligament in dogs. The results of the statistical analysis showed that multi-faceted reconstruction allows the secondary determination of the oblique imaging planes and obtains images of adequate quality. CONCLUSION: It can be concluded that multi-faceted reconstruction facilitates the secondary determination of oblique imaging planes. This reconstruction additionally makes images available of better quality compared to the 2D sequence.

Clinical Applications of Imaging Modalities of the Carpal Joint in Dogs with Particular Reference to the Carpal Canal.

The structure of the canine carpal joint is complex. This small joint consists of articulations that include the antebrachiocarpal, middle, carpometacarpal, and intercarpal joint surfaces. A large number of ligaments and tendons support and stabilise the carpus in dogs. Many injuries of this joint in dogs are not correctly recognised, diagnosed, or treated due to the limited use of diagnostic imaging methods. Radiography, the most common of them, has extensive application in diagnosing the causes of lameness in small animals. Other techniques, such as ultrasonography, computed tomography, and magnetic resonance imaging visualise other joint structures and surrounding soft tissues. However, these imaging modalities are rarely used to diagnose diseases and injuries of the canine carpus at present. The main reason for this is the small amount of research carried out and the lack of a properly described methodology for the use of imaging techniques. The wide use of all diagnostic imaging tools in the diagnosis of diseases and injuries of the wrist joint in humans shows that conducting studies on dogs could expand current knowledge. The use of these techniques in veterinary medicine could facilitate diagnosis and subsequent therapy of carpal disorders in dogs. MRI is the most frequently used imaging method in human medicine for visualisation of abnormalities of joints. This method could become a valuable part of the detection of inflammatory, traumatic, and degenerative diseases of the carpal joint in dogs.

Feline hip joint anatomy in magnetic resonance images.

The aim of this study was to develop an anatomical model of the feline hip joint for low-field magnetic resonance imaging (LF-MRI) based on high-field magnetic resonance imaging (HF-MRI). The study was performed on six adult clinically healthy European shorthair cats, aged 1-3 years, with body weight of 2.8-4.4 kg. The animals were examined with the use of the Vet-MRI Grande Esaote LF (0.25 T) scanner and high-field Siemens Magnetom TRIO (3 T) MRI scanner. In the LF-MRI, most satisfactory results in T1-weighted images were obtained when TE was 26 ms in all three planes and when TR was 350-950 ms in the transverse plane, 950-1150 ms in the sagittal plane and 520-750 ms in the dorsal plane. In T2-weighted images, TE was 90 ms in the transverse and dorsal plane and 120 ms in the sagittal plane. The results were presented as images acquired with LF-MRI scanners in three planes. The slice thickness was 3 mm for each plane. In LF-MRI, muscles in the hip joint region and round ligament were well visualized. Unlike in LF-MRI, the cross section of the femoral nerve was identified in HF-MRI scans. In examinations of the feline hip joint, the main limitations of LF-MRI were a lack of reliable contrast between articular cartilage and synovial fluid as well as longer scan time. Despite the above, LF-MRI images were characterized by good contrast between bones and the surrounding soft tissues.

The Influence of Haemostatic Dressing Prototypes for the Emergency Services on the Histopathological Parameters of Porcine Muscle.

BACKGROUND/AIM: Haemostatic dressings for the uniformed and rescue services are an integral part of life-saving equipment for controlling post-traumatic haemorrhage. The aim of this study was to assess the influence of active constituent substances and materials of haemostatic dressings on muscle tissue and muscle regeneration after traumatic injury. MATERIALS AND METHODS: Three hemostatic dressing prototypes were analysed: OBR/G/S sponge: dressing material sponge made of Na-Ca chitosan/algal composite microfibers and nanofibers; OBR/MBT/S: tactic gauze modified with a polymer mixture of Na-Ca chitosan/algal composite microfibers and nanofibers, impregnated with a moderate amount of procoagulants (22.9 g/m2); and OBR/MS/S: seton gauze modified with a polymer mixture of Na-Ca chitosan/algal composite microfibers and nanofibers, impregnated with a moderate amount of procoagulants (18.0 g/m2), with chitosan (ChitoClearhqg 95) and sodium alginate (Protanal LF10/60 FT) as the coagulants. The experiment was conducted on 20 pigs which were euthanised 24 h, 7 or 14 days after wound dressing. Samples of porcine muscle tissue were subjected to qualitative histopathological analysis. RESULTS: Histopathological analysis of muscle tissues from the experimental pigs revealed that the application of modified seton (OBR/MS/S) produced the most satisfactory results. The observed changes were similar on all dates that samples were collected and in all experimental groups, and minor differences in their extent were observed between groups. Regenerative processes were most advanced, and retrograde changes were least apparent in animals treated with OBR/MS/S. CONCLUSION: Modified seton (OBR/MS/S) induced the least tissue reaction and was most effective in promoting tissue regeneration after injury.

The Effect of Haemostatic Dressing Prototypes for the Emergency Services in the Porcine Haemostatic System.

BACKGROUND/AIM: Coagulopathy can develop when hemostatic dressings are used to stop massive bleeding, even in patients without prior history of clotting disorders. The selection of procoagulants, which effectively control bleeding and prevent disseminated intravascular coagulation (DIC) and thrombosis, is a significant challenge. The aim of this study was to evaluate the effect of two prototypes of haemostatic dressing in the porcine haemostatic system. MATERIALS AND METHODS: The total number of animals used in our experiments was 24. Group I: pigs were treated with the developed prototype of sponge dressing, made of Na-Ca chitosan/algal composite of microfibers and nanofibers. Group II: animals were treated with a seton gauze modified with a polymer mixture of Na-Ca chitosan/algal composite of microfibers and nanofibers. Group III: animals were treated with non-hemostatic dressing and this group was the control. Blood was sampled five times to determine changes in the coagulation and fibrinolytic profiles: before injury: i) at 1 h, ii) at 24 h, iii) at 7, and iv) at 14 days following injury. RESULTS: Significant changes were observed in the coagulation parameters, in the total numbers of white blood cells and platelets in groups I and II, compared to controls. CONCLUSION: The modified haemostatic dressings used in this study produced a strong procoagulant effect in pigs. This, together with high fibrinogen concentrations, which can cause DIC, require further studying.