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.

Subtotal Pericardiectomy and Epicardiectomy for Treatment of Septic Pericarditis and Constrictive Epicarditis in a Dog.

A 1 yr old, 1.7 kg, spayed female Chihuahua was presented for respiratory distress and an enlarged cardiac silhouette as seen on thoracic radiographs. Echocardiogram revealed pericardial effusion and cardiac tamponade. Computed tomography revealed marked pleural and pericardial effusion, thickening of the pericardium caudally, and a mass along the mediastinum. Pericardial fluid obtained via pericardiocentesis showed suppurative inflammation with mixed anaerobic bacteria isolated on culture. Subtotal pericardiectomy and partial lung lobectomy was performed to treat septic pericarditis. Postoperative echocardiogram showed increased right-sided pressures consistent with constrictive epicarditis, and 10 days after surgery, the dog was re-presented for right-sided heart failure. An epicardectomy was performed. A definitive source of infection was not identified, although a penetrating foreign body (e.g., grass awn) was suspected. The dog recovered and 10 yr follow up revealed no evidence of constrictive pathology on echocardiogram. This case report demonstrates the successful treatment of septic pericarditis and constrictive epicarditis via subtotal pericardiectomy and epicardiectomy.

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.

Delayed union, non-union and mal-union in 442 dogs.

OBJECTIVES: (1) To estimate the prevalence of delayed union, non-union and mal-union in canine fractures; (2) to describe fracture, demographic, and treatment characteristics for these outcomes; (3) to identify risk factors for delayed or non-union. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Four hundred and forty two dogs (461 fractures). METHODS: A review was conducted of clinical records and radiographs from 2 teaching hospitals. "Union," "delayed union," "non-union" and "mal-union" were defined, and fracture, demographic, treatment, and outcome variables described. Differences in proportions or medians between "union," "delayed union" and "non-union" were tested using χ2 and Mann-Whitney U-tests for categorical and continuous variables respectively. Potential explanatory variables for "delayed or non-union" were tested using logistic regression to identify risk factors. RESULTS: Median radiographic follow up was 53 days (14-282). Delayed union occurred in 13.9% of fractures (64/461), non-union in 4.6% (21/461), and mal-union in 0.7% (3/461). Risk factors for delayed or non-union were age (OR 1.21, 95% CI 1.12-1.31); comminuted fracture (OR 4.24, 95% CI 2.4-7.5); treatment with bone graft (all types) (OR 3.32, 95% CI 1.3-8.5); surgical site infection (OR 3.24, 95% CI 1.17-8.97), and major implant failure (OR 12.94, 95% CI 5.06-33.1). CONCLUSION: Older dogs, dogs with comminuted fractures, surgical site infection, or major implant failure were at increased odds of delayed or non-union. Radius and ulna fractures in toy breed dogs were not at increased odds of delayed or non-union. CLINICAL SIGNIFICANCE: The identified risk factors should inform fracture planning and prognosticating. The prognosis for radial fractures in toy breeds appears better than historically believed.

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.

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.