The impact of surgery resident training on the duration of tibial plateau leveling osteotomy surgery.

OBJECTIVE: To investigate the impact of surgery resident training on surgery duration in tibial plateau leveling osteotomy (TPLO) and evaluate whether surgery duration differs with each year of residency training. STUDY DESIGN: Retrospective medical record review. ANIMALS: A total of 256 client-owned dogs underwent TPLO. METHODS: Records of dogs that underwent TPLO between August 2019 and August 2022 were reviewed. The effects of the surgeon (faculty/resident) and the procedure (arthrotomy/arthroscopy) on TPLO surgery duration were examined with an analysis of variance, and geometric least squares means (GLSM) were compared. A linear mixed effects model (LMM) was fitted to quantify fixed and random effects. RESULTS: Four faculty surgeons performed 74 (29%) TPLOs, while 10 residents performed 182 (71%) TPLOs under the direct supervision of a faculty surgeon. All TPLOs were conducted with arthrotomy (109; 43%) or arthroscopy (147; 57%). Overall, residents (GLSM, 153 min) required 54% more surgery duration than faculty surgeons (GLSM, 99 min). Surgery duration among first-year residents (GLSM, 170 min) was 15% longer than second- (GLSM, 148 min) and third-year (GLSM, 147 min) residents, whereas the duration did not differ statistically between second- and third-year residents. Arthroscopy, meniscal tear treatment, surgery on the right stifle, and increasing patient weight were also associated with longer surgery duration. CONCLUSION: The duration of TPLO surgery significantly decreased after the first year of residency, but did not decrease afterward. CLINICAL SIGNIFICANCE: The results will aid with resource allocation, curricula planning, and cost management associated with resident training.

K-wire is more damaging than standard or acrylic drill bits when evaluating torsional properties of rabbit (Oryctolagus cuniculi) femurs.

OBJECTIVE: The objective of this study is to compare drilling variables and torsional mechanical properties of rabbit femora after bicortical drilling with a 1.5-mm standard surgical drill bit, acrylic drill bit, and K-wire. SAMPLES: 24 pairs of rabbit femora. METHODS: After drilling under controlled axial displacement rate, each bone was biaxially loaded in compression followed by rapid external torsion to failure. Maximum axial thrust force, maximum drill torque, integral of force and displacement, change in temperature, maximum power spectral density of the torque signal, torque vibration, and torque and angle at the yield and failure points were collected. Pre- and postyield stiffness, yield and failure energies, and postyield energy were calculated. RESULTS: The work required to drill through the cis- and transcortices (integral of force and displacement) was greater for the K-wire, followed by the acrylic and then standard drill bits, respectively. The K-wire demonstrated higher maximum torque than the drill bits at the ciscortex, and the force of drilling was significantly greater. The vibration data was greater with the acrylic and standard drill bits than the K-wire. There was no difference in torsional strength between drilling types. CLINICAL RELEVANCE: Mechanical differences exist between different drill bits and K-wire and demonstrate that the K-wire is overall more damaging than the surgical drill bit.

Outcomes of 11 dogs with short radius syndrome treated with acute arthroscopically assisted ulnar shortening.

OBJECTIVE: To describe the short-term outcome of acute arthroscopically assisted ulnar shortening (AUS), to treat short radius syndrome in dogs. STUDY DESIGN: Case series. ANIMALS: Eleven client owned dogs. METHODS: Records of dogs that had undergone AUS for treatment of short radius syndrome were reviewed for inclusion. Reporting data included among others pre- and postoperative radioulnar, humeroradial and humeroulnar distances, lameness scores, surgical times, complications and clinical outcome. RESULTS: Following AUS, radiohumeral articulation was improved in all dogs. Median presurgery radioulnar, humeroradial and humeroulnar values were 4.5, 3.2, and 2.2 mm and were improved with surgery by a median of 3.2, 1.8, and 1.2 mm, respectively. Median surgery time was 140 min. Median time to bone healing was 8 weeks (range: 4-14). Median time to last follow-up was 9 weeks (4-468). Median lameness score (scale 0-4) improved from 2 to 1. No major complications were reported. Short-term clinical outcome was graded by the surgeons as full function in four cases and acceptable function in seven. CONCLUSION AND CLINICAL RELEVANCE: Radiographic and arthroscopic radiohumeral articulation were improved and short-term clinical improvement was documented following AUS in all 11 dogs.

Biomechanical comparison of compact versus standard flute drill bits, and interlocking versus buttress thread self-tapping cortical bone screws in cadaveric equine third metacarpal condyle.

OBJECTIVES: To compare (1) performance of compact versus standard flute drill bits, (2) screw insertion properties and (3) pullout variables between interlocking thread (ITS) and buttress thread (BTS) self-tapping screws in third metacarpi. STUDY DESIGN: In vitro experimental study. SAMPLE POPULATION: Paired third metacarpi from 11 Thoroughbreds aged 2-4 years. METHODS: Screws were inserted into the lateral condylar fossae following bone preparation using the respective drill bit for each screw type. Screw pullout was achieved using a mechanical testing system. Density and porosity of bone surrounding screw holes was measured with microcomputed tomography following each pullout test. Drilling, screw insertion and pullout variables were compared between drill bit and screw types using repeated measures ANOVA. Linear regression analyses were used to characterize relationships between bone tissue properties and drill bit and screw outcomes. RESULTS: Maximum torque power spectral density (PSD) was lower for compact flute drill bits. Insertion torque was 50% higher for ITS. BTS had 33% greater preyield stiffness and 7% greater mean yield force. Bone tissue properties affected measured variables similarly for both screw and drill bit types. CONCLUSIONS: Lower torque PSD may increase durability of the compact flute drill bit. ITS had greater insertional torque, which may reflect greater bone engagement. BTS had greater resistance to axial pullout forces. CLINICAL SIGNIFICANCE: Metacarpal bone provides a simple model for comparison of drill bit and screw designs. Use of ITS to repair equine fractures subject to predominantly tensile forces is not justified based on the results of this study.

Number of previous surgeries and antibiotic resistance decreases the success of local administration of antibiotic-impregnated poloxamer 407 hydrogel when managing orthopedic surgical site infections in dogs.

OBJECTIVE: To report the outcome of locally administered antibiotic-impregnated poloxamer 407 (P407) hydrogel in dogs diagnosed with orthopedic surgical site infections (SSIs) and to identify risk factors for treatment failure. ANIMALS: 34 client-owned dogs diagnosed with an orthopedic surgical site infection treated with local antibiotic-impregnated P407 hydrogel. PROCEDURES: Medical records were reviewed of dogs receiving antibiotic-impregnated P407 hydrogel for an active orthopedic SSI between March 2018 and December 2020. The rate of successful infection clearance was calculated. Risk factors for failed treatment were evaluated with statistical analyses. RESULTS: 34 dogs met the inclusion criteria. Vancomycin-impregnated P407 hydrogel (20 mg/mL) was implanted in all dogs. The rate of infection clearance was 77%. Each unit increase in the number of surgeries performed at a site before gel implantation decrease the chance of successful infection clearance by 25% (P = .005; unit OR, 0.25; 95% CI, 0.08 to 0.81). Presence of multidrug or methicillin resistance increased risk for treatment failure by 7.69 times (P = .042; OR, 0.13; 95% CI, 0.01 to 1.14). No adverse events related to gel administration were seen. CLINICAL RELEVANCE: Treatment outcomes were negatively impacted by the presence of multidrug or methicillin resistance and by an increased number of surgeries before gel implantation. Local administration of antibiotic-impregnated P407 hydrogel had a high success rate with no adverse effects in this population. Local antibiotic gel administration may improve treatment outcomes in dogs with complicated SSI.

Metal reactivity is present in dogs with tibial plateau leveling osteotomy and total hip replacement implants.

OBJECTIVE: Determine whether dogs with well-functioning orthopedic metal implants can develop metal reactivity. SAMPLE: Client-owned dogs that had tibial plateau leveling osteotomy (TPLO) or total hip replacement (THR) implants for 12 months or more and control dogs with no implants. PROCEDURES: Lymphocyte transformation testing was performed by exposing peripheral blood lymphocytes to nickel (Ni), chromium (Cr), cobalt (Co), or a combination of these metals. Lymphocyte proliferation was assessed with flow cytometry. Lymphocyte stimulation indexes (SIs) were calculated. A SI > 2 was considered reactive. Median SIs of dogs in response to metal exposure were compared statistically. RESULTS: Samples from 10 dogs with TPLO, 12 dogs with THR, and 7 control dogs were analyzed. Six dogs out of 22 with metal implants had a reactive SI to 1 or more metals, while 2 of 7 control dogs had a SI > 2 when exposed to nickel only. When all metals were considered, no differences in metal reactivity were found between TPLO, THR, and control groups. CLINICAL RELEVANCE: Metal reactivity is present in dogs and can be identified using lymphocyte transformation testing. Reactivity to Ni is present in dogs with and without metal implants. Reactivity to Co and Cr occurs in some dogs with metal implants.

Long-Term Assessment of Bone Regeneration in Nonunion Fractures Treated with Compression-Resistant Matrix and Recombinant Human Bone Morphogenetic Protein-2 in Dogs.

OBJECTIVE: The aim of this study was to assess bone density, bone architecture and clinical function of canine nonunion distal appendicular long bone fractures with a defect treated with fixation, compression-resistant matrix and recombinant human bone morphogenetic protein-2 (rhBMP-2). STUDY DESIGN: Prospective cohort study with dogs at least 1-year post treatment. Computed tomography was performed and quantitative measurements from previous fracture sites were compared with measurements from contralateral limbs. Subjective evaluation included gait assessment and palpation. RESULTS: Six patients met the inclusion criteria. The rhBMP-2 treated bone exhibited higher density at the periphery and lower density in the centre, similar to the contralateral limb. All patients were weight bearing on the treated limb and all fractures were healed. CONCLUSION: The rhBMP-2-treated bone underwent restoration of normal architecture and density. Acceptable limb function was present in all patients. The results of this study can serve as a basis for long-term response in treating nonunion fractures in veterinary patients.

Results of using multiplanar reconstructed CT images for assessing elbow joint osteoarthritis in dogs are consistent with results of radiographic assessment.

OBJECTIVE: To compare osteoarthritis scores assigned through radiographic evaluation of 18 anatomic regions in the elbow joint with scores assigned through evaluation of 3-D maximum intensity projection (MIP), 3-D surface rendering (TSR), and multiplanar reconstructed (MPR) CT images, and to evaluate intraobserver and interobserver agreement of radiographic and CT scoring. SAMPLE: Radiographic and CT images of 39 elbow joints in 20 dogs. PROCEDURES: Images were anonymized and graded independently by 5 observers. One observer graded 12 elbow joints 3 times. Intraobserver consistency and repeatability, interobserver agreement, consistency among methods, and bias between methods were calculated. RESULTS: The most severe changes were observed at the proximal aspect of the anconeal process, and the medial and cranial aspects of the medial coronoid process. Intraobserver consistency was moderate or better for 11/16 regions with MIP images, 11/16 regions with TSR images, 17/18 regions with MPR images, and 14/18 regions with radiographic images. Interobserver agreement was moderate or better for 5/16 regions with MIP images, 9/16 regions with TSR images, 12/18 regions with MPR images, and 6/18 regions with radiographic images. Mean scores from CT-based methods were higher than mean radiographic scores. CLINICAL RELEVANCE: Assessments of osteoarthritis severity in the elbow joints of dogs obtained by examining radiographic images were generally consistent with assessments obtained by examining CT scans. MPR scores were more consistent and more comparable to radiographic scores than were MIP or TSR scores.

Tissue Engineering of Canine Cartilage from Surgically Debrided Osteochondritis Dissecans Fragments.

This study in dogs explored the feasibility of using cartilage fragments removed and discarded during routine palliative surgery for osteochondritis dissecans (OCD) as a source of primary chondrocytes for scaffold-free cartilage tissue-engineering. Primary chondrocytes were obtained from three OCD donors and one age-matched healthy articular cartilage (HAC) donor. After monolayer expansion of primary cells, a three-dimensional spherical suspension culture was implemented. Following this stage, cells were seeded at a high density into custom-made agarose molds that allowed for size and shape-specific constructs to be generated via a method of cellular self-assembling in a scaffold-free environment. Fifty-eight neocartilage constructs were tissue-engineered using this methodology. Neocartilage constructs and native cartilage from shoulder joint were subjected to histological, mechanical, and biochemical testing. OCD and HAC chondrocytes-sourced constructs had uniformly flat morphology and histology consistent with cartilage tissue. Constructs sourced from OCD chondrocytes were 1.5-times (32%) stiffer in compression and 1.3 times (23%) stronger in tension than constructs sourced from HAC chondrocytes and only 8.7-times (81%) less stiff in tension than native tissue. Constructs from both cell sources consistently had lower collagen content than native tissue (22.9%/dry weight [DW] for OCD and 4.1%/DW for HAC vs. 51.1%/DW native tissue). To improve the collagen content and mechanical properties of neocartilage, biological and mechanical stimuli, and thyroid hormone (tri-iodothyronine) were applied to the chondrocytes during the self-assembling stage in two separate studies. A 2.6-fold (62%) increase in compressive stiffness was detected with supplementation of biological stimuli alone and 5-fold (81%) increase with combined biological and mechanical stimuli at 20% strain. Application of thyroid hormone improved collagen content (1.7-times, 33%), tensile strength (1.8-times, 43%), and stiffness (1.3-times, 21%) of constructs, relative to untreated controls. Collectively, these data suggest that OCD chondrocytes can serve as a reliable cell source for cartilage tissue-engineering and that canine chondrocytes respond favorably to biological and mechanical stimuli that have been shown effective in chondrocytes from other animal species, including humans.

Perception of gender discrimination among spine surgeons across Latin America: a web-based survey.

BACKGROUND CONTEXT: Female physicians rarely choose spine surgery as their specialty. Although the specialty's nature and its associated lifestyle are potential barriers, gender-related issues may play an important part. PURPOSE: To evaluate the gender discrimination among spine surgeons across Latin America. STUDY DESIGN: Cross-sectional survey. PATIENT SAMPLE: The participants in this study were 223 AO Spine Latin America (AOSLA) registered members who answered the web-based survey. OUTCOME MEASURES: Personal and professional demographics; gender-related objective and subjective experiences regarding career and personal life. METHODS: A survey link containing a 24-item questionnaire was sent to the members' e-mails in September 2019. The survey was designed to evaluate the perception of gender discrimination by spine surgeons during their academic and professional lives. RESULTS: Out of 223 members who answered the survey, 196 (87.96%) were male and 27 (12.11%) female. Most were orthopedic surgeons (64.13%), ≥40 years of age (55.16%), and had <20 years of experience (69.95%). Gender discrimination was more frequent among women than among men (66.67% vs. 1.02%), as did discouragement from becoming a spine surgeon, orthopedic surgeon, or neurosurgeon (81.48% vs. 0.51%). Females reported higher rates of sexual harassment (44.44% vs. 7.65%) and more often felt disadvantaged because of gender (55.56% vs. 2.55%). Working harder than men to achieve the same prestige and lack of female mentorship were the most common obstacles reported by women (55.56%). Residency/fellowship influenced the decision to postpone/avoid having children for 66.67% of women but only 37.75% of men. Creation of a Women's Committee in AO Spine was supported by 74.07% of women and 38.78% of men. CONCLUSIONS: Gender-based discrimination affects women more frequently than men in spine surgery. These experiences likely contribute to the low prevalence of female spine surgeons. Efforts to mitigate bias and support the professional development of women in neurosurgery, orthopedics and spine communities are encouraged.

Training Surgical Residents Utilizing an Animal Shelter Fracture Program.

Working relationships between veterinary medical teaching hospitals, animal shelters, and rescue groups are one way to increase veterinary students' and residents' hands-on training. The goal of this study is to describe the use of a shelter fracture program to improve the surgical skills of surgical residents. In this program, the participating shelter and rescue organizations electronically submit cases. Following evaluation of radiographs and case approval by the orthopedic faculty, the case is scheduled for a physical evaluation. A resident takes primary surgical care together with a fourth-year student rotating through the orthopedic surgery service to ensure the proper pre-, peri-, and post-operative standard of care. All care is overseen by the orthopedic faculty. A veterinary student-run fracture foster program allows students to gain additional experience in the pre-, peri-, and post-operative care of shelter animals. The total number of shelter animals treated during a 9-year period was 373, with a mean annual case load of 41.1 cases (± 10.3). During the same time period, a total of 435 client-owned cases underwent surgical fracture treatment, with a mean annual case load of 48 cases (± 11.7). Surgical resident and student surveys show that this program contributes to their knowledge, skills, and confidence in treating fracture patients. A successful cooperative program provides advanced surgical fracture treatment of shelter animals, improving animals' quality of life as well as surgical residents' and veterinary students' skills training.

Influence of interlocking thread screws to repair simulated adult canine humeral condylar fractures.

OBJECTIVE: To determine the influence of interlocking screw threads on the biomechanical properties of repaired canine humeral condylar fractures. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: Thirty-six humeral condyles. METHODS: Simulated fractures of the lateral aspect of the humeral condyle were stabilized by a 3.5 mm interlocking thread screw (ITS) or 3.5 mm buttress thread screw placed in lag (BTS-L) or positional fashion (BTS-P) and axially loaded at a walk, trot, 2-mm displacement, and failure cycles. Compact flute drill bits (CFBs) were used for ITS constructs and standard flute drill bits (SFB) for BTS constructs. The effects of bit type on drilling parameters and screw type on screw insertion properties and fragment stability were assessed. RESULTS: CFB produced a 6°C greater temperature increase (p = .042) and required 20 N higher torque (p = .003) than SFB. Insertional torque was greater for ITS than BTS-P (p = .001) and BTS-L (p = .001). Condylar fragment rotation at failure was lower in ITS (lsmean ± SE, 8.3° ± 1.9°) than BTS-L constructs (14.5° ± 2.3°, p = .011). ITS resisted greater loads (1503 ± 105 N) than BTS-P (1189 ± 99 N, p = .038) but not BTS-L (1249 ± 123 N, p = .121) constructs. CONCLUSION: Biomechanical performance of constructs was improved with ITS rather than BTS fixation. CLINICAL SIGNIFICANCE: ITS can be considered for stabilization of humeral condylar fractures in adult dogs.

Comparison of 18F-sodium fluoride positron emission tomography and CT: An exploratory study in 12 dogs with elbow pain.

18F-Sodium Fluoride (18F-NaF) positron emission tomography (PET) provides high resolution functional information about bone activity and can be fused with CT images to improve three-dimensional localization and characterization of lesions. This prospective, observational study assessed 18F-NaF PET-CT for imaging of canine elbows, compared PET with CT findings, and assessed correlation with lameness. Twelve patients with elbow pain were included. Cases included primarily young, large breed dogs. A three-level clinical lameness score was assigned to each forelimb. All dogs had bilateral elbow joints imaged with CT and PET under general anesthesia, approximately 1.5 h after intravenous injection of 3 MBq/kg of 18F-NaF. Imaging findings were independently reviewed by two radiologists using a three-level scoring scheme over nine anatomical regions in the elbow. PET imaging identified areas of bone activity where minimal change was identified on CT. PET imaging also demonstrated absence of uptake in areas where modeling was present on CT. A stronger correlation was observed between clinical grades and PET scores (r2  = 0.38, P = .001) than between clinical grades and CT scores (r2  = 0.17, P = .048). The total PET scores were significantly different for each clinical grade (P = .013) but total CT scores did not differ (P = .139). This exploratory study suggests that PET improves the ability to detect lesions and to determine the clinical significance of CT findings in dogs with elbow pain.

Comparison of needle arthroscopy, traditional arthroscopy, and computed tomography for the evaluation of medial coronoid disease in the canine elbow.

OBJECTIVE: To evaluate the diagnostic value of still images of needle arthroscopy (SNAR), still images of traditional arthroscopy (STAR), and computed tomography (CT) to diagnose medial coronoid process (MCP) pathology. STUDY DESIGN: Prospective clinical trial. ANIMALS: Dogs (n = 17) presented for evaluation of elbow dysplasia. METHODS: For each case, two SNAR and STAR images of the MCP were reviewed independently and in random order by three board-certified surgeons. Computed tomographic images were reviewed by one board-certified radiologist. Reviewers were blinded to surgical and clinical findings. Surgical findings from real-time TAR with palpation were used as the gold standard. Receiver operating characteristic (ROC) curves and concordance statistics tests for the diagnostic accuracy of MCP fissure, MCP fragment, medial compartment condition, and cartilage score were calculated. RESULTS: Images of 27 elbows joints were reviewed. For MCP fissure detection, areas under the ROC curves for CT (0.84), STAR (0.73), and SNAR (0.57) did not differ. For the detection of MCP fragment, STAR had a larger area under the ROC curve (0.93) compared with SNAR (0.74, P = .015) and CT (0.54, P < .001). Still images of TAR and SNAR had comparable concordance for cartilage score (0.80 and 0.77, respectively) and medial compartment pathology (0.80 and 0.73, respectively). CONCLUSION: Still images of NAR, STAR, and CT had similar diagnostic value to identify MCP fissures. Still images of TAR was superior to SNAR and CT to identify MCP fragments. CLINICAL SIGNIFICANCE: The diagnostic accuracy of SNAR varied on the basis of the coronoid lesion being evaluated.

Comparison of torsional properties between a Fixateur Externe du Service de Santé des Armées and an acrylic tie-in external skeletal fixator in a red-tailed hawk (Buteo jamaicensis) synthetic tibiotarsal bone model.

OBJECTIVE: To compare the torsional mechanical properties of 2 external skeletal fixators (ESFs) placed with 2 intramedullary pin (IP) and transfixation pin (TP) size combinations in a model of raptor tibiotarsal bone fracture. SAMPLE: 24 ESF-synthetic tibiotarsal bone model (polyoxymethylene) constructs. PROCEDURES: Synthetic bone models were fabricated with an 8-mm (simulated fracture) gap. Four types of ESF-synthetic bone model constructs (6/group) were tested: a FESSA with a 1.6-mm IP and 1.6-mm TPs, a FESSA with a 2.0-mm IP and 1.1-mm TPs, an acrylic connecting bar with a 1.6-mm IP and 1.6-mm TPs, and an acrylic connecting bar with a 2.0-mm IP and 1.1-mm TPs. Models were rotated in torsion (5°/s) to failure or the machine angle limit (80°). Mechanical variables at yield and at failure were determined from load deformation curves. Effects of overall construct type, connecting bar type, and IP and TP size combination on mechanical properties were assessed with mixed-model ANOVAs. RESULTS: Both FESSA constructs had significantly greater median stiffness and median torque at yield than both acrylic bar constructs; FESSA constructs with a 1.6-mm IP and 1.6-mm TPs had greatest stiffness of all tested constructs and lowest gap strain at yield. No FESSA constructs failed during testing; 7 of 12 acrylic bar constructs failed by fracture of the connecting bar at the interface with a TP. CONCLUSIONS AND CLINICAL RELEVANCE: Although acrylic bar ESFs have been successfully used in avian patients, the FESSA constructs in this study were mechanically superior to acrylic bar constructs, with greatest benefit resulting from use with the larger TP configuration.

Gender differences in academic rank among faculty surgeons at US veterinary schools in 2019.

OBJECTIVE: To describe academic rank, gender, surgical career length, and publication record of academic veterinary surgeons and to estimate the association between gender and higher academic rank. STUDY DESIGN: Cross-sectional study. SAMPLE: Residency-trained surgeons at US veterinary schools in 2019. METHODS: Surgeons were identified via institutional websites. Data including surgeon gender, academic title, and year of board certification were collected from public resources. Publication record was measured by using author h-indices obtained from Scopus. Data were analyzed with descriptive and inferential statistics. RESULTS: Three hundred eighteen surgeons were identified from 30 institutions, including 162 (51%) women and 156 (49%) men. Women represented 66% of instructors and assistant professors, and men represented 60% of associate and full professors. This distribution differed significantly (P < .001). Author h-index was associated with career length but not gender. Men were 2.5 times more likely than women to be associate or full professors (odds ratio 2.52, 95% CI 1.03-6.14, P = .042) after adjustment for career length and h-index. CONCLUSION: Female surgery faculty at US veterinary schools in 2019 were concentrated in lower academic ranks and were less likely than male surgery faculty to be associate or full professors after adjustment for career length and publication record. IMPACT: A gender gap exists in academic veterinary surgery in the United States. It is critical to recognize that women's increasing participation in veterinary medicine has not been matched by equal representation in all areas. Additional efforts are warranted to identify contributing factors and implement strategies to improve gender inclusion.

Release Rates and Complications for Birds of Prey With Antebrachial Fractures at a Veterinary Teaching Hospital.

A retrospective case series that included 253 free-ranging birds of prey admitted to a rehabilitation center was conducted to describe the treatment and outcome of antebrachial fractures. Medical records from birds of prey belonging to 21 species admitted with antebrachial fracture between 1989 and 2015 at the University of California, Davis, were reviewed. Species distribution on admission, treatment, outcome, and complications were described by fracture category and species. Among 134 birds treated after initial triage on the day of admission, 4 bone/ wing categories were identified: 83 birds had an ulnar fracture only; 18 birds had a radial fracture only; 28 birds had a concomitant fracture of the radius and ulna on the same wing; and 5 birds had bilateral antebrachial fractures. Logistic regressions were performed to determine which factors were associated with a positive outcome within each of these 4 categories. Among birds having only an ulnar fracture, those with a closed fracture were significantly more likely to be released than birds with open fractures (P = .03; odds ratio = 5.43, 95% confidence interval: 1.29-28.12). In addition, birds with a fracture of the middle third of the ulna were significantly more likely to be released than birds diagnosed with a single fracture of the proximal third of the ulna (P = .02; odds ratio = 4.54, 95% confidence interval: 1.35-16.64). No significant prognostic factor was detected in other fracture categories.

Comparative histomorphometric analysis of cellular phenotype in canine stifle ligaments and tendon.

OBJECTIVE: To measure the density of cellular phenotypes in canine caudal cruciate ligament (CaCL), cranial cruciate ligament (CrCL), medial collateral ligament (MCL), and long digital extensor tendon (LDET). STUDY DESIGN: Ex-vivo study. METHODS: Ten CaCL, CrCL, MCL, and LDET obtained from 1 stifle of 10 dogs with no gross pathology were analyzed histologically. The density of cells with 3 nuclear phenotypes (fusiform, ovoid, and spheroid) was determined within the core region of each specimen. RESULTS: Cells with fusiform nuclei were most dense in the MCL (median [range], 319 [118-538] cells/mm2 ) and LDET (331 [61-463]), whereas cells with ovoid nuclei were most dense in the CaCL (276 [123-368]) and CrCL (212 [165-420]). The spheroid nuclear phenotype had the lowest density in all structures (31 [5-61] in CaCL, 54 [5-90] in CrCL, 2 [0-14] in MCL, and 5 [0-80] in LDET); however, the CrCL contained a denser population of spheroid cells compared with MCL and LDET (P < .05). Total cell densities did not differ among the 4 structures (P > .05). CONCLUSION: Phenotype density varied within the ligaments and tendon tested here. The cell population of CaCL and CrCL differed from that of dense collagenous tissues such as MCL and LDET. CLINICAL SIGNIFICANCE: The relatively higher density of spheroid phenotype in CrCL may reflect a distinctive native cellular population or a cellular transformation secondary to unique mechanical environment or hypoxia. This intrinsic cellular population may explain altered tissue properties prone to pathological rupture or poor healing potential of the canine CrCL.

Radiation exposure of dogs and cats undergoing fluoroscopic procedures and for operators performing those procedures.

OBJECTIVE: To evaluate radiation exposure of dogs and cats undergoing procedures requiring intraoperative fluoroscopy and for operators performing those procedures. SAMPLE: 360 fluoroscopic procedures performed at 2 academic institutions between 2012 and 2015. PROCEDURES: Fluoroscopic procedures were classified as vascular, urinary, respiratory, cardiac, gastrointestinal, and orthopedic. Fluoroscopy operators were classified as interventional radiology-trained clinicians, orthopedic surgeons, soft tissue surgeons, internists, and cardiologists. Total radiation exposure in milligrays and total fluoroscopy time in minutes were obtained from dose reports for 4 C-arm units. Kruskal-Wallis equality of populations rank tests and Dunn pairwise comparisons were used to compare differences in time and exposure among procedures and operators. RESULTS: Fluoroscopy time (median, 35.80 minutes; range, 0.60 to 84.70 minutes) was significantly greater and radiation exposure (median, 137.00 mGy; range, 3.00 to 617.51 mGy) was significantly higher for vascular procedures than for other procedures. Median total radiation exposure was significantly higher for procedures performed by interventional radiology-trained clinicians (16.10 mGy; range, 0.44 to 617.50 mGy), cardiologists (25.82 mGy; range, 0.33 to 287.45 mGy), and internists (25.24 mGy; range, 3.58 to 185.79 mGy). CONCLUSIONS AND CLINICAL RELEVANCE: Vascular fluoroscopic procedures were associated with significantly longer fluoroscopy time and higher radiation exposure than were other evaluated fluoroscopic procedures. Future studies should focus on quantitative radiation monitoring for patients and operators, importance of operator training, intraoperative safety measures, and protocols for postoperative monitoring of patients.

Effects of Hole Diameter on Torsional Mechanical Properties of the Rabbit Femur.

OBJECTIVE: The aim of this study was to evaluate and compare the effect of three clinically applicable screw hole diameters on rabbit femoral torsional structural properties. SAMPLE: Eighteen pairs of skeletally mature New Zealand White rabbit femora (36 bones). MATERIALS AND METHODS: Femora with a bicortical hole at mid-diaphysis from one of the 3-drill bit sizes, 1.1 mm, 1.5 mm, 2.0 mm, and intact bones were studied. Each bone was bi-axially loaded in a servo-hydraulic load frame with the bone positioned so the neutral axis of torsion was aligned with the centre of the bone diaphysis. Axial compression to 35% body weight was applied to represent compression at stance, and rapid external torsion was applied to failure. Torque and angular deformation data were plotted for each test, with pre-yield and post-yield stiffnesses derived. Yield and failure torques and angles were determined, along with calculated yield, failure and post-yield energies. RESULTS: Failure torque was reduced compared with that of intact bone; weakened by 37% in 1.1-mm hole models, 53% in 1.5-mm hole models and 65% in 2.0-mm hole models. The torque angular deformation curves lacked plastic deformation. CONCLUSIONS AND CLINICAL RELEVANCE: This study demonstrates the unique, brittle biomechanics of rabbit bone. Based on data from other species that strength loss of no more than 50% is acceptable when placing orthopaedic implants, no defect greater than 1.1 mm (15% bone diameter) is recommended in rabbit femora.