Utilizing 3-dimensional models to assess keel bone damage in laying hens throughout the lay cycle.

The global egg industry is rapidly transitioning to cage-free egg production from conventional cages. Hens housed in cage-free systems have an increased prevalence of keel damage that could lead to reduced egg production and compromised well-being. The objective of this study was to determine the effects of dietary supplementation of n-3 fatty acids and vitamin D3 on keel damage in hens housed in multi-tier aviary systems (AV). Brown hens were placed in 4 AV system rooms after rearing at 17 wk of age (woa) with each room containing 576 birds. At 12 woa, rooms were randomly assigned to a dietary treatment of flaxseed oil, fish oil, vitamin D3, or control. Focal birds (36 per treatment) were longitudinally examined for keel damage using quantitative computed tomography (QCT) at nine timepoints from 16 to 52 woa. Three-dimensional digital twins of the keels were created from the QCT scans and visually assessed for damage. An overall keel severity score was recorded as well as the location, direction, and severity of each deviation or fracture. Severity was ranked on a 0 to 5 scale with 0 being no damage and 5 being severe. Damage scores were analyzed utilizing odds ratios with main effects of age and treatment. At 16 woa, 80% of hens had overall keel scores of 0 and 20% had scores of 1. At 52 woa, all hens had damage, with 31% having a score of 1, 61% scored 2 to 3, and 8% scored 4 to 5. Most fractures were not observed until peak lay. Dietary treatments did not affect likelihood of fracture incidences, but younger birds had lower odds of incurring keel fractures than older birds (P < 0.0001). The initial incidences of keel deviations occurred earlier than fractures, with most birds obtaining a keel deviation by 28 woa. Keel damage was not able to be prevented, but the age at which keel fractures and deviations initiate appear to be different, with deviations occurring during growth and fractures during lay.

[Navicular bone fractures in horses: Prognosis after conservative and surgical treatment]. / Strahlbein-Frakturen beim Pferd: Prognose nach konservativer und chirurgischer Therapie.

INTRODUCTION: The aim of this retrospective study is to describe and compare conservative and surgical treatment of navicular fractures in horses. An attempt is made to identify critical points that can favorably influence the prognosis of this orthopedic disease. All horses treated for a navicular fracture at the Equine Clinic, Vetsuisse Faculty, University of Zurich between 2005 and 2017 were included in this study. The severity of lameness at initial examination, radiographic assessment, hoof conformation, treatment (conservative or surgical), complications and outcome were determined from the medical records. Conservative and surgical treatment consisted of stable rest, a controlled exercise program and therapeutic orthopedic shoeing. During surgical treatment, fracture reduction was also carried out with a cortical screw. Computer assisted surgery were used in five horses and computer tomography in three horses. Follow-up examinations included clinical and radiographic examinations. The outcome was divided into three categories: 1 = very good; 2 = good; 3 = poor. Twelve horses met the inclusion criteria; Four horses were treated conservatively and eight were treated surgically. After conservative treatment, two horses (50 %) had a very good outcome and two (50 %) had a good outcome. After surgical treatment, four horses (50 %) had a very good outcome and four (50 %) had a poor outcome. Overall, 67 % of horses had a very good or good outcome, although radiographic signs of bone healing was not present in any of these cases. Various complications were identified, such as the fracture of a screw, the fragmentation of the small navicular bone fragment, the development of osteoarthrosis in the coffin joint and progressive podotrochosis. This study shows that the prognosis of navicular fractures is generally cautious and that degenerative changes to the navicular apparatus worsen the prognosis. In the present study, surgical treatment did not improve the prognosis of navicular fractures despite the intrasurgical use of three-dimensional imaging. However, technical advances could reduce the complication rate in the future.

INTRODUCTION: Le but de cette étude rétrospective était de décrire et de comparer le traitement conservateur et chirurgical des fractures de l'os naviculaires chez le cheval. Une tentative est faite pour identifier les points critiques qui peuvent influencer favorablement le pronostic de cette maladie orthopédique. Tous les chevaux traités pour une fracture de l'os naviculaire à la Clinique équine de la Faculté Vetsuisse de l'Université de Zurich entre 2005 et 2017 ont été inclus dans cette étude. La gravité de la boiterie lors de l'examen initial, l'évaluation radiographique, la conformation du sabot, le traitement (conservateur ou chirurgical), les complications et le résultat ont été déterminés à partir des dossiers médicaux. Le traitement conservateur et chirurgical consistait en un repos au box, un programme d'exercice contrôlé et un ferrage orthopédique thérapeutique. Au cours du traitement chirurgical, une réduction de la fracture a également été effectuée à l'aide d'une vis corticale. La chirurgie assistée par ordinateur a été utilisée sur cinq chevaux et la tomographie assistée par ordinateur sur trois chevaux. Les examens de suivi comprenaient des examens cliniques et radiographiques. Les résultats ont été divisés en trois catégories: 1 = très bon; 2 = bon; 3 = mauvais. Douze chevaux répondaient aux critères d'inclusion ; quatre chevaux ont été traités de manière conservatrice et huit ont été traités chirurgicalement. Après un traitement conservateur, deux chevaux (50 %) ont eu un très bon résultat et deux (50 %) un bon résultat. Après le traitement chirurgical, quatre chevaux (50 %) ont eu un très bon résultat et quatre (50 %) un mauvais résultat. Dans l'ensemble, 67 % des chevaux ont eu un très bon ou un bon résultat, bien que les signes radiographiques de guérison osseuse n'aient été présents dans aucun de ces cas. Diverses complications ont été identifiées, telles que la fracture d'une vis, la fragmentation du petit fragment de l'os naviculaire, le développement d'une arthrose dans l'articulation interphalangienne distale et une podotrochlose progressive. Cette étude montre que le pronostic des fractures de l'os naviculaire est généralement réservé et que les modifications dégénératives de l'appareil naviculaire aggravent le pronostic. Dans la présente étude, le traitement chirurgical n'a pas amélioré le pronostic des fractures du naviculaire malgré l'utilisation intra-chirurgicale de l'imagerie tridimensionnelle. Cependant, les progrès techniques pourraient réduire le taux de complications dans le futur.

Successful surgical management of a Salter-Harris type I fracture of the accessory carpal bone in a dog.

OBJECTIVE: To describe the successful surgical management of a previously unreported Salter-Harris type I fracture of the accessory carpal bone in a dog. ANIMAL: An 11-week-old intact female Golden Retriever-Poodle cross presented with a history of a marked left forelimb lameness following a suspected fall from a height. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: On physical examination, the patient demonstrated a severe left forelimb lameness and pain on palpation and range of motion of the left carpus. Orthogonal radiographs of the distal left forelimb demonstrated a type I Salter-Harris fracture of the accessory carpal bone with proximal displacement of the palmar fragment. TREATMENT AND OUTCOME: The patient underwent open reduction and internal fixation wherein the fracture was reduced and stabilized with two 1.1-mm Kirschner wires. Postoperatively, the patient was initially managed with a carpal flexion bandage for 2 weeks and then a soft padded bandage was maintained until 4 weeks postoperatively. The patient recovered well and was walking and weight-bearing comfortably following removal of the carpal flexion bandage. Repeat radiographs performed 4 and 8 weeks postoperatively demonstrated adequate fracture healing but showed mild proximocaudal implant displacement. Implant removal was not performed, as the patient was doing well at home and the implant migration appeared static and was not causing clinical morbidity. CLINICAL RELEVANCE: To the authors' knowledge, this was the only reported case of a Salter-Harris fracture of the accessory carpal bone in a dog and the only described case of successful surgical stabilization.

Outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning.

OBJECTIVE: To report the outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning (FGNMP). STUDY DESIGN: Retrospective case series. ANIMALS: A total of 15 client owned dogs and two cats with 57 metabone fractures. METHODS: Description of FGNMP and reporting of the following data: signalment, pre- and postoperative radiographs, intramedullary pin diameter used, anesthesia, surgery and coaptation times, duration to normal weightbearing and bone union, postoperative care and complications. RESULTS: Median surgery time was 54 min (range: 26-99), median duration of coaptation was 14 days (range: 1-5 weeks), median time to normal weightbearing was 16 days (range: 2-45) and median time to bone union was 6 weeks (range: 4-12). All cases had at least 12 months of post-surgical follow-up with a median follow-up of 18 months (range: 12-70). No major complications occurred. Mild radiographic changes associated with subchondral bone sclerosis were noted on follow-up radiographs in 13/57 fractures. All cases returned to normal gait and full (15) or acceptable (2) function. CONCLUSION: In this study, FGNMP was an effective and safe technique for metabone fracture repair, requiring only short-term external coaptation in most patients. Time to bone union and return to normal function compared favorably to previously reported techniques. CLINICAL RELEVANCE: Fluoroscopically guided normograde metabone pinning provides an alternative technique for treatment of metabone fractures.

Mechanical Testing of Sliding on Pivot-Locking Clamp (SOP-LC) Fracture Repair System in Four-Point Bending and Torsion.

OBJECTIVES: The first objective of this study was to compare the mechanical performance of a straight and contoured rod for the sliding on pivot-locking clamp (SOP-LC) system. The second objective was to compare single-cycle bending and torsion of the SOP-LC rod-bone constructs to a bone gap model between two clamp configurations. STUDY DESIGN: First experiment, 5 mm diameter rods from the 3.5 mm SOP-LC system, 4 straight and 4 bent rods were mechanically compared in four-point bending. The second experiment, 8 constructs with clamps on a single side of the rod and 8 constructs with clamps on alternating sides were compared in four-point bending and torsion. A torque limiting screwdriver at 2.5N was used for all constructs. RESULTS: There were not significant differences between the noncontoured versus contoured rods. Constructs with clamps on a single side had a significantly higher yield load, yield displacement and bending strength, but the constructs with alternating clamps had a significantly higher initial torsional stiffness. There were no other significant differences. Mild clamp slippage and mild screw bending were noted in all the torsion tested constructs graphically with multiple stiffness slopes and visually on the post-tested constructs. CONCLUSION: Torque applied to initial screw placement may play a role in reducing clamp slippage. Although bending yield load, bending yield displacement, bending strength and torsional stiffness were improved by different clamp placement, clinically this will depend on fracture type. Further studies are needed for clinical significance.

Factors associated with keel bone damage - a longitudinal study of commercial layer flocks during the laying period.

1. Keel bone damage, such as deformations and fractures, is a severe problem regarding animal welfare in layers. To identify risk factors under commercial conditions, 33 layer flocks (22 barn, 11 free range) with white (n = 18), brown (n = 11) and mixed (n = 4) genotypes were examined.2. Keel bone status was frequently scored by palpation throughout the laying period. Data on housing and management conditions were collected. Multiple regression and Generalized Estimating Equations procedure were used for analysis.3. At 65-74 weeks of age, the prevalence of keel bone damage ranged between 26% and 74%. White genotypes and those kept in multi-tier systems developed significantly (p < 0.05) more keel bone damage than brown genotypes or those kept in single-tier systems. Wing feather condition was associated with keel bone damage (p < 0.05), while other investigated variables regarding health, housing and management were not associated.4. In conclusion, housing and management should be adapted to meet the birds' specific needs in multi-tier systems, which may vary for brown and white genotypes. Whether those differences result from genotype associated predispositions or other individual traits remains to be determined.

Surgical excision of P3 fragments in 86 declawed cats: case series (2013-2023).

CASE SERIES SUMMARY: This case series describes the clinical findings and surgical intervention of 86 declawed cats; 52 from a shelter or rescue and 34 owned cats. Historical reports from owners and shelter staff included house-soiling, biting behavior, repelling behavior, barbering, lameness, chronic digit infection and nail regrowth. All the cats had fragments of the third phalanx (P3) of varying sizes diagnosed on radiographs. Pathology visible on examination included digital subcutaneous swelling, ecchymosis, malaligned digital pads, ulcerations, exudate, tendon contracture, nail regrowth and callusing. Surgery was pursued in these cases to remove the P3 fragments, relieve tendon contracture and reposition the digital pads with an anchoring suture. Gross findings intraoperatively included fragmented growth of cornified and non-cornified nail tissue, osteophytes on the surface of the second phalanx, deep digital flexor tendon calcification, and both bacterial and sterile exudate. The most common complication 14 days postoperatively was mild (14%) to moderate (1%) lameness. All historical parameters recorded improved in both populations of cats (house-soiling, biting behavior, repelling behavior, barbering, lameness, tendon contracture and chronic digit infection). Postoperatively, 1/47 cats exhibited continued malalignment of two digital pads and there were no reports of long-term postoperative lameness. RELEVANCE AND NOVEL INFORMATION: Two methods of declawing cats are detailed in the veterinary literature, including partial amputation of P3 and disarticulation of the entire P3 bone. The novel information in this report includes historical and clinical signs of declawed cats with P3 fragments, intraoperative gross pathology, surgical intervention and the postoperative follow-up results.

Influence of screw configuration on reduction and stabilization of simulated complete lateral condylar fracture in equine limbs.

OBJECTIVE: To determine the influence of screw configuration on the reduction and stabilization of simulated complete lateral condylar fracture. STUDY DESIGN: Randomized experimental crossover study. METHODS: A lateral condylar fracture was simulated in 18 cadaver limbs from nine horses. Each limb underwent repair with 4.5 mm diameter cortex screws, tightened to 4 Nm, in a linear and triangular configuration. Computed tomography (CT) of each repair was performed with the limbs in unloaded and loaded conditions. Fracture gaps were measured at the dorsal, palmar, and middle locations of the third metacarpal condyle. Fracture gap measurements were graded 0-4, based on voxels. Following descriptive analysis, a Bayesian network (BN) model was fitted to the data. RESULTS: The median fracture grade was 0 (range: 0-4) for unloaded linear repairs and 2 (0-4) for loaded linear repairs. The median fracture grade was 0 (0-3) for unloaded triangular repairs and 1 (0-3) for loaded triangular repairs. Bayesian network sensitivity analysis showed that the construct configuration reduced the uncertainty in the measured fracture outcome by 0.8%. CONCLUSION: Triangular screw configuration resulted in better fracture reduction and stability in comparison with linear screw configuration. However, the BN sensitivity analysis results showed that the effect of construct configuration on fracture outcome was weak. CLINICAL SIGNIFICANCE: These findings indicate a low probability that triangular repair of lateral condylar fracture will result in improved outcomes, when compared with linear repair.

Influence of keel impacts and laying hen behavior on keel bone damage.

Keel bone damage, which presents as fractures and/or deviations of the keel, has been detected in laying hens housed in all types of systems. Factors leading to keel bone damage in hens housed with limited vertical space, such as those housed in furnished systems, are not well understood, and are the topic of this study. Ten focal hens from each of 12 furnished cages (4 rooms of 3 cages) were fitted with keel mounted tri-axial accelerometers. Their behavior was video recorded continuously over two 3-wk trials: the first when the hens were between 52 and 60 wk of age, and the second approximately 20 wk later. The integrity of each hen's keel was evaluated at the start and end of each 3-wk trial using digital computed tomography. We identified predominant behaviors associated with acceleration events sustained at the keel (collisions, aggressive interactions and grooming) by pairing accelerometer outputs with video data. For each recorded acceleration event we calculated the acceleration magnitudes as the maximum summed acceleration recorded during the event, and by calculating the area under the acceleration curve. A principle components analysis, which was used as a data reduction technique, resulted in the identification of 4 components that were used in a subsequent regression analysis. A key finding is that the number of collisions a hen has with structures in her environment, and the number of aggressive interactions that a hen is involved, each affect the likelihood that she will develop 1 or more fractures within a 3-wk time span. This relationship between hen behavior and keel fracture formation was independent of the magnitude of acceleration involved in the event. Observed behavior did not have an impact on the formation of keel bone deviations, further supporting reports that the mechanisms underlying the 2 types of keel bone damage are different.

Feline radial and ulnar diaphyseal fractures: a retrospective study of 49 cases comparing single bone fixation and dual bone fixation.

OBJECTIVES: The objectives of this study were to report the complications in radial and ulnar diaphyseal fractures in cats and to compare the differences in outcome between single and dual bone internal fixation. METHODS: Medical records between 2004 and 2022 were searched retrospectively for cats with antebrachial diaphyseal fractures treated with internal bone-plate fixation. In total, 49 cases were included from six referral hospitals, including one teaching hospital. Patient information was collated, including fracture configuration, location, repair method and clinical outcome as assessed by veterinary physical examination, radiography and owner questionnaire. RESULTS: A total of 47 cats (mean age 4.2 years) were included. Fractures were located distally (24/49, 49%), proximally (13/49, 26.5%) and mid-diaphyseally (12/49, 24.5%). Dual bone fixation was used in 13/49 (26.5%) cases, with only 1/13 (7.7%) having major complications. By comparison, 4/36 (11.1%) of single plated fractures had major complications. Single bone fixation was 14.25 times more likely (95% confidence interval [CI] 2.07-97.99) to have a successful outcome (veterinarian-assigned score of 0) compared with dual bone fixation (P = 0.007). When evaluating owner-assessed outcomes, single bone fixation was 9.4 times more likely (95% CI 1.4-61.96) to have a successful outcome (owner score of 0) compared with dual bone fixation (P = 0.019). CONCLUSIONS AND RELEVANCE: Fractures that were repaired with single bone fixation had a greater chance of a better outcome. Although the difference was not significant, there was a higher major complication rate and a lower minor complication rate for cases treated with single bone fixation compared with dual bone fixation. The majority of fractures were located in the distal diaphysis. Comminution of the fracture and concurrent orthopaedic issues did not significantly affect the outcome. Further prospective studies with standardised follow-up, radiographic assessment, surgeon and implants are required to truly assess the difference between dual and single bone fixation.

Sacral fracture stabilisation using dorsal transiliac locking plates: 12 cases (2017-2023).

OBJECTIVES: To describe the clinical presentations, outcomes and complications associated with the use of dorsal transiliac locking plates to stabilise sacral fractures in dogs and cats. MATERIALS AND METHODS: A single-centre retrospective analysis of all patients that presented with sacral fractures between February 2017 and February 2023 that were managed surgically using paired dorsal transiliac locking plates. Twelve animals met the criteria for inclusion in a retrospective clinical case series. An owner questionnaire was employed to assess long-term outcomes. RESULTS: Eleven dogs and one cat with a mean age of 3.1 years (range 0.6 to 8.8) were included. Eleven patients presented following a motor vehicle accident and most were either non-ambulatory (n=8) or displayed severe unilateral hindlimb lameness (n=4). Nine sacral fractures were considered Anderson type II and three Anderson type V. The plate fixation was augmented with additional surgical stabilisation in 11 cases. Eleven patients were ambulatory at discharge and all cases healed uneventfully without major surgical or postoperative complications. Long-term follow-up (>60 days) was available in 10 animals at a mean of 694 days (range 65 to 1805) and owner-assessed outcomes via questionnaire were reported as good to excellent in all cases. CLINICAL SIGNIFICANCE: The application of transiliac locking plates provided sufficient stability to facilitate sacral fracture healing with minimal clinical complications. This method represents a robust and safe option to stabilise sacral fractures in dogs and cats, offering an alternative to iliosacral lag screw fixation.

Effect of an Orthogonal Locking Plate and Primary Plate Working Length on Construct Stiffness and Plate Strain in an In vitro Fracture-Gap Model.

OBJECTIVE: The aim of this study was to compare stiffness and strain of an in vitro fracture-gap model secured with a primary 3.5-mm locking compression plate (LCP) at three primary plate working lengths without and with an orthogonal 2.7-mm LCP. STUDY DESIGN: Primary plate screw configurations modeled short working length (SWL), medium working length (MWL), and long working length (LWL) constructs. Construct stiffness with and without an orthogonal plate during nondestructive four-point bending and torsion, and plate surface strain measured during bending, was analyzed. RESULTS: Single plate construct stiffness was significantly, incrementally, lower in four-point bending and torsion as working length was extended. Addition of an orthogonal plate resulted in significantly higher bending stiffness for SWL, MWL, and LWL (p < 0.05) and torsional stiffness for MWL and LWL (p < 0.05). Single plate construct strain was significantly, incrementally, higher as working length was extended. Addition of an orthogonal plate significantly lowered strain for SWL, MWL, and LWL constructs (p < 0.01). CONCLUSION: Orthogonal plate application resulted in higher bending and torsional construct stiffness and lower strain over the primary plate in bending in this in vitro model. Working length had an inverse relationship with construct stiffness in bending and torsion and a direct relationship with strain. The inverse effect of working length on construct stiffness was completely mitigated by the application of an orthogonal plate in bending and modified in torsion.

Fractures in Thoroughbred racing and the potential for pre-race identification of horses at risk.

Risk rates for and predisposing factors to fractures occurring in Thoroughbred racing that have been published in peer reviewed journals are documented. The potential for currently available techniques to identify horses at increased risk for fracture is discussed on the bases of principles, practicalities, advantages, disadvantages and current data. All are reviewed in light of justifiable decision making and importance of fractures to horseracing's social license.

Efficacy of a novel cervical dislocation tool for humane euthanasia of broilers and broiler breeders.

Euthanasia is an essential task performed daily on commercial poultry farms around the world to safeguard animal welfare. Manual cervical dislocation (MCD) is the most common euthanasia method but can be challenging to perform given the physical strength required to implement this technique. Therefore, the objective of this study was to evaluate the efficacy of a novel cervical dislocation tool (NCDT) compared to MCD. A total of 60 Ross 308 chickens (6-wk old) and 60 Ross 706 parent stock breeders (21-wk old) were enrolled in the study. Birds were sexed, blocked by body weight, and allocated to 1 of 2 treatments: 1) MCD and 2) NCDT. Immediately following euthanasia application, insensibility, and death were monitored. Once death was confirmed, gross evaluation, radiograph, and macroscopic/microscopic scoring were performed. Both euthanasia methods were 100% effective in achieving insensibility followed by cardiac and respiratory arrest in both age groups. In 6-wk-old broilers, there were no differences in insensibility measures or location and severity of the dislocation site by treatment. The NCDT treatment group showed an increased frequency of fractures located at the tooth-like process that projects from the cranial aspect of the centrum of the axis (dens) but had no impact on bird insensibility. For parent stock, differences in nictitating membrane reflex (NMR) and laceration scores for birds euthanized with NCDT were found and likely associated with additional force exerted with the tool. The NCDT is a promising replacement for MCD and future work should address the development of free and accessible training materials for on-farm use.

Inspection of chicken wings and legs for animal welfare monitoring using X-ray computed tomography, visual examination, and histopathology.

In broiler chickens, fractures of wings and legs are recorded at poultry slaughterhouses based on the time of occurrence. Prekilling (PRE) fractures occur before the death of animal, so the chicken was still able to experience pain and distress associated with the injury (an animal welfare issue). Postkilling (POST) fractures occur when the chickens are deceased and fully bled-out and consequently unable to feel pain (not an animal welfare issue). Current practice dictates that fractures are recognized visually and recorded by the animal welfare officers as mandated by European Union and/or national regulations. However, new potential monitoring solutions are desired since human inspection suffers from some significant limitations including subjectivism and fatigue. One possible solution in detecting injuries is X-ray computed tomography (CT) scanning and in this study we aim to evaluate the potential of CT scanning and visual inspection in detecting limb fractures and their causes. Eighty-three chicken wings and 60 chicken legs (n = 143) were collected from a single slaughterhouse and classified by an animal welfare officer as PRE, POST or healthy (HEAL). Samples were photographed and CT scanned at a veterinary hospital. The interpretation of CT scans along with photographs took place in 3 rounds (1. CT scans only, 2. CT scans + photographs, 3. photographs only) and was performed independently by 3 veterinarians. The consistency of the interpretation in 3 rounds was compared with the animal welfare officer's classification. Furthermore, selected samples were also analyzed by histopathological examination due to questionability of their classification (PRE/POST). In questionable samples, presence of hemorrhages was confirmed, thus they fit better as PRE. The highest consistency between raters was obtained in the 2nd round, indicating that interpretation accuracy was the highest when CT scans were combined with photographs. These results indicate that CT scanning in combination with visual inspection can be used in detecting limbs fracture and potentially applied as a tool to monitor animal welfare in poultry slaughterhouses in the future.

AN ANATOMICAL STUDY OF THE THORACIC LIMB OF THE GIANT ANTEATER (MYRMECOPHAGA TRIDACTYLA) COMPARED WITH THE DOMESTIC DOG TO GUIDE SURGICAL APPROACHES TO THE HUMERUS AND RADIUS.

The giant anteater (Myrmecophaga tridactyla) is a neotropical mammal considered to be vulnerable to extinction. Recent increased interest in veterinary care in the giant anteater has prompted renewed interest in anatomical descriptions in this species. The terrestrial habits and slow movements of the giant anteater contribute to its susceptibility to vehicular trauma on highways, which is a significant cause of mortality in the species. This study describes the muscular anatomy of the thoracic limb and variations of the long bones with emphasis on the structures surrounding the humerus and radius. It also describes the possible surgical approaches for the management of fractures of humerus and radius, comparing these with the surgical approaches described in dogs (Canis lupus familiaris). Three giant anteater and three domestic dog cadavers, from deaths not related to this project, were used. The medial approach to the humeral diaphysis of the giant anteater resulted in the least tissue trauma, and provided access to the flattest surface for implant attachment. The lateral approach to the radius proved challenging, requiring total detachment of the extensor carpi radialis muscle and incision of the very robust abductor digitorum longus muscle to access the distal diaphysis. Although the giant anteater shares many similarities of the thoracic limb anatomy with the domestic dog, important differences exist. This comparative knowledge will allow veterinary practitioners to directly apply the principles of fracture repair in these species. Safe access to these bones for possible osteosynthesis is essential to allow implant placement and minimize postoperative complications in this species.

Effect of Plate-Bone Distance and Working Length on 2.0-mm Locking Construct Stiffness and Plate Strain in a Diaphyseal Fracture Gap Model: A Biomechanical Study.

OBJECTIVE: The aim of this study was to determine the effect of plate-bone distance (PBD) and working length on 2.0-mm locking compression plate (LCP) stiffness and strain in four-point bending and torsion in a diaphyseal fracture gap model. STUDY DESIGN: A total of 54 LCP with three screws per fragment were assigned to one of nine combinations of working length (WL; short, medium, and long), and PBD (1, 1.5, and 3 mm) for a sample size of six per construct configuration. Stiffness was measured under quasistatic, nondestructive four-point compression bending and torsion. Plate surface strain was recorded using three-dimensional (3D) digital image correlation during four-point compression bending. RESULTS: WL had a significant effect on overall construct stiffness in both compression bending and in torsion, with shorter WL constructs having higher stiffness (p < 0.0001). PBD had no effect on construct stiffness in compression bending; however, a significant reduction in stiffness was noted in torsion (p = 0.047) as PBD incrementally increased. WL had a significant effect on plate strain in compression bending, with shorter WL constructs having lower plate strain (p < 0.0001). PBD had no effect on plate strain in compression bending except for lower plate strain recorded in long WL constructs with 1-mm PBD, compared with 1.5- and 3-mm PBD constructs (p < 0.0001). CONCLUSION: Longer WL constructs, regardless of PBD, had lower stiffness in compression bending, while in torsion, some modulation of this effect was noted with incremental decreases in PBD. Longer WL resulted in high plate strain, regardless of PBD.

Use of Locking Plates Fixed with Cortical Screws for Pelvic Fracture Repair in 20 Cats.

OBJECTIVE: The aim of this study is to describe the use of String of Pearls (SOP) plates for the surgical management of feline pelvic fractures, including surgical technique, proposed indications, complications, and outcomes in a cohort of cats. STUDY DESIGN: This study is a single-center retrospective clinical case series. METHODS: Medical records (2015-2019) of cats presenting for pelvic fractures (n = 33) were reviewed. Type of fracture, preoperative and postoperative imaging, and complications were retrospectively retrieved. Owners were contacted via questionnaire for medium- and long-term follow-up. RESULTS: A total of 20 cats met the inclusion criteria. Minor intraoperative complications were encountered in three patients. One patient suffered a major intraoperative complication. Five major complications were encountered postoperatively. These included two greater trochanter osteotomy fixation implant removal and three SOP plate removal. Full function was recovered in all patients according to the owners' assessment. CLINICAL SIGNIFICANCE: The use of SOP plates in feline pelvic fractures appears to yield a consistently good outcome with a very low incidence of canal narrowing and screw loosening. SOP plates are easy to contour and to apply along the entire pelvic length.

Positron emission tomography assessment of metacarpal/metatarsal condylar fractures post surgical repair: Prospective study in 14 racehorses.

OBJECTIVES: To assess 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) findings associated with metacarpal/metatarsal condylar fractures at the time of fracture repair and through healing. STUDY DESIGN: Prospective descriptive study. ANIMALS: Fourteen Thoroughbred racehorses. METHODS: 18F-NaF PET was performed within 4 days of surgical metacarpal/metatarsal condylar fracture repair, on both the injured and contralateral limb. Follow-up PET scans were offered at 3- and 5-months post fracture repair. Areas of abnormal uptake were assessed using a previously validated grading system. RESULTS: Eight fractures were located in the parasagittal groove (PSG) (six lateral and two medial) and six fractures were located abaxial to the PSG (non-PSG) through the palmar/plantar condyle (all lateral). All horses in the latter group had uptake in the lateral palmar condyle of the contralateral limb suggestive of stress remodeling. Three horses with PSG fractures had uptake in a similar location in the contralateral limb. Horses with lateral condylar fracture only presented minimal or mild uptake in the medial condyle, which is considered atypical in the front limbs for horses in full training. Four horses developed periarticular uptake in the postoperative period suggestive of degenerative joint disease, three of these horses had persistent uptake at the fracture site. These four horses did not return to racing successfully. CONCLUSION: The findings of this study provide evidence of pre-existing lesions and specific uptake patterns in racehorses suffering from metacarpal/metatarsal condylar fractures. CLINICAL SIGNIFICANCE: PET has a possible role in the prevention, diagnosis, and postoperative monitoring of metacarpal/metatarsal condylar fractures in racehorses.