Arthroscopic Caudal Cruciate Ligament Damage in Canine Stifles with Cranial Cruciate Ligament Disease.

OBJECTIVE: The aim of this study was to describe the arthroscopic changes to the caudal cruciate ligament (CdCL) in dogs with cranial cruciate ligament disease. STUDY DESIGN: Arthroscopic video recordings (n = 117) of the stifle with cranial cruciate ligament disease were reviewed. The extent of CdCL tearing was described. Signalment, palpable stifle stability and the presence of a meniscal tear were recorded. Pathology of the synovial joint and the synovium overlying the CdCL were scored at two time points.Two-way interactions were investigated (p < 0.05). Univariate analysis and a Wald test (p < 0.20) were performed. Factors were retained with a Wald test p < 0.05 or if a confounder, then a changing model coefficient >15%. A weighted kappa statistic was used to evaluate intraobserver agreement. RESULTS: Caudal cruciate ligament tearing was identified in 94% of stifles. Longitudinal tearing (76%) was the most common type of damage (45% partial, 31% full thickness). Synovitis was present in all joints and changes to the synovium overlying the CdCL were less frequently identified (67%).Synovitis was associated with the degree to CdCL tearing. Synovitis overlying the CdCL was associated with lower body weight and lower CdCL damage. CONCLUSION: Caudal cruciate ligament damage is common in dogs with cranial cruciate ligament disease and longitudinal tearing was the most common injury identified. Severity of joint pouch synovitis was positively correlated with the degree of CdCL damage and the portion of the CdCL not exposed to the synovium was unaffected. These findings suggest synovitis is likely a contributor to CdCL injury.

Arthroscopic Articular Cartilage Scores of the Canine Stifle Joint with Naturally Occurring Cranial Cruciate Ligament Disease.

OBJECTIVE: This study aimed to evaluate frequency, location and severity of cartilage pathology in dogs with naturally occurring cranial cruciate ligament (CCL) disease. STUDY DESIGN: Stifle arthroscopic video recordings (n = 120) were reviewed. A modified Outerbridge classification system (MOCS) (0-4) was used to score cartilage at 10 locations in the femorotibial (medial and lateral femoral condyles and tibial plateaus) and patellofemoral compartments (proximal, middle and distal locations of the patella and femoral trochlear groove) of the stifle joint. Synovial pathology was scored and the presence of a medial meniscal tear was recorded. A Kruskal-Wallis test was used to evaluate association of location and synovitis with cartilage score; and presence of meniscal tear with cartilage and synovitis scores. Bonferroni correction was utilized and p < 0.05 was considered significant. RESULTS: Cartilage pathology and synovitis were identified in all joints. Overall cartilage severity scores were low (median MOCS 1). The median MOCS of the proximal trochlear groove (2) was significantly higher than all other locations evaluated. Higher synovitis scores were significantly associated with higher cartilage severity scores and a medial meniscal tear had no association with cartilage severity scores or synovitis. CONCLUSION: Arthroscopic articular cartilage lesions are common in dogs with CCL disease at the time of surgical intervention, although the severity of cartilage damage is mild. The proximal trochlear groove of the femur had the most severe cartilage score in the stifle joint.

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.

Observer Variability of Arthroscopic Cartilage Grading Using the Modified Outerbridge Classification System in the Dog.

OBJECTIVE: The aim of this study was to determine the inter- and intra-observer variability of the modified Outerbridge cartilage classification system in canine joints evaluated via arthroscopy. MATERIALS AND METHODS: Fifty arthroscopic videos of canine cartilage were scored by six observers, where three of the observers had significant arthroscopic experience and three had minimal to no experience. The kappa (κ) statistic was used to evaluate overall and individual score inter-observer variability, as well as experience variability. The weighted κ statistic was used to evaluate the overall intra-observer variability for each observer, and for individual score intra-observer variability across experience groups. Landis and Koch cut-offs were used to determine strength of agreement associated with each κ-value. RESULTS: The overall inter-and intra-observer variability of the modified Outerbridge cartilage classification system showed fair and substantial strengths of agreement, respectively. The most extreme scores of 0 and 4 had the best inter- and intra-agreement and the middle scores of 1, 2 and 3 had decreased strengths of agreement. Experience of the observer increased the strength of agreement between the scores. CLINICAL SIGNIFICANCE: The modified Outerbridge classification system is an acceptable method for the evaluation of canine cartilage. Observer agreement is improved if the observer has experience with arthroscopy and viewing cartilage changes, and if the same observer is used for subsequent cartilage evaluations.

Proximal tibial metaphyseal fractures in immature dogs.

OBJECTIVE: To describe proximal tibial metaphyseal fractures in immature dogs. MATERIALS AND METHODS: Medical records of immature dogs with metaphyseal fractures of the proximal tibia were reviewed and data were collected on signalment and history of trauma. Craniocaudal and mediolateral radiographs were evaluated for the determination of the bones fractured, location of the fracture within the bone, fracture configuration, and the presence of fracture segment displacement and angulation. RESULTS: Eighteen dogs with 22 proximal tibial metaphyseal fractures fulfilled the inclusion criteria. All fractures had a curvilinear, complete fracture of the proximal tibial metaphysis. Displacement was identified in 16 fractures and angulation in 15 fractures. All affected breeds were terrier or small breed dogs less than six months of age. The majority of dogs weighed less than or equal to 5 kg at the time of injury. The most common type of trauma that occurred was a jump or fall from a short distance. CLINICAL SIGNIFICANCE: Proximal tibial metaphyseal fractures are an uncommon injury that occur in skeletally immature dogs from minimal trauma. Proximal tibial metaphyseal fractures have a characteristic curvilinear fracture configuration that affects mainly small breed dogs with a predominance for terrier breeds.

Factors associated with pathological fractures in dogs with appendicular primary bone neoplasia: 84 cases (2007-2013).

OBJECTIVE: To determine the incidence of pathological fractures associated with appendicular primary bone tumors in dogs managed medically and to identify potential risk factors at the time of radiographic diagnosis that may be associated with eventual pathological fracture. DESIGN: Retrospective case series. ANIMALS: 84 dogs with primary long bone neoplasia treated medically. PROCEDURES: Medical records for dogs with a diagnosis of primary long bone neoplasia based on results of radiography that was confirmed subsequently at necropsy were reviewed. Owners elected medical treatment at a pain clinic. Data regarding clinical signs, diagnostic testing, pathological findings, and outcome were evaluated. RESULTS: 84 dogs met study inclusion criteria with 85 limbs affected. Osteosarcoma was the most common tumor and was identified in 78 of 85 (91.8%) limbs. The median time from diagnosis to euthanasia was 111 days (range, 28 to 447 days). Pathological fractures were identified in 33 of 85 limbs (38%), with the femur most commonly affected, (8/14 [57.1%]), followed by the tibia (9/17 [52.9%]), humerus (10/27 [37%]), radius (5/25 [20%]), and ulna (1/2 [50%]). Logistic regression analysis indicated that tumors arising from long bones other than the radius had odds of eventual fracture 5.05 as great as the odds for tumors of the radius, and lytic tumors had odds of eventual fracture 3.22 as great as the odds for tumors that appeared blastic or mixed lytic-blastic. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that radial primary bone tumors were less likely and lytic tumors were more likely to fracture. The overall incidence of pathological fractures secondary to appendicular primary bone neoplasia in this study with patients treated by means of intensive management for bone pain was higher than previously reported.

Articular cartilage lesions of the patellofemoral joint in dogs with naturally occurring cranial cruciate ligament disease.

OBJECTIVE: To evaluate frequency, severity, and location of patellofemoral (PF) osteoarthritis (OA) in dogs with naturally occurring cranial cruciate ligament (CCL) disease. STUDY DESIGN: Cross-sectional observational study. ANIMALS: Dogs (n = 40; stifles, 44). METHODS: Stifle arthroscopic video recordings and radiographs were performed. Cartilage pathology was scored at 3 locations (proximal, middle, distal) in the trochlear groove and patella. A radiographic osteoarthrosis and synovial pathology score were assigned. A Kruskal-Wallis test was used to determine if lesion severity varied by site, synovitis, and osteoarthrosis, and the Dunn's test was used for pairwise comparisons. The variability of body weight was evaluated using 1 way ANOVA; P < .05 was considered significant. RESULTS: Cartilage pathology and synovitis was identified in all PF joints. The proximal aspect of the trochlear groove had significantly higher cartilage scores than the middle and distal sites and the middle groove site was significantly higher than the distal site. The distal aspect of the patella had significantly greater scores than the middle and proximal patellar locations. Higher synovitis scores were associated with increased cartilage scores. Cartilage scores were significantly greater in stifles with higher radiographic osteophytosis, tibial sclerosis, and patellar enthesiophytosis scores. Higher body weights were significantly associated with greater synovial and radiographic scores. CONCLUSIONS: Dogs with CCL disease have a high incidence of PF cartilage pathology and the severity of cartilage lesions varies depending on location within the joint.

The effect of abaxial retraction on pelvic geometry after pelvic symphysiotomy.

OBJECTIVE: To describe the effect abaxial retraction after pelvic symphysiotomy has on the geometry of the sacroiliac joints (SIs) in dogs. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Canine cadavers (n = 9). METHODS: Canine cadavers free of sacroiliac disease had pelvic symphysiotomy and retraction to 25%, 50%, 75%, and 100% of transverse sacral width, followed by axial reduction of the symphysis. Before symphysiotomy, after each abaxial retraction value, and after reduction of the symphysis each SI joint had a computed tomographic scan to evaluate the effect on the SI joints. RESULTS: There was no luxation at 25% abaxial retraction, unilateral SI luxation in three cadavers after 50% abaxial retraction and in all cadavers after 75% abaxial retraction. Axial reduction of the symphysis resolved all luxations. CONCLUSIONS: Pelvic symphysiotomy and abaxial retraction between 50% and 75% of transverse sacral width leads to unilateral SI luxation, which is resolved by axial reduction. While not likely requiring ancillary stabilization, SI joint luxation may be a cause for additional postoperative pain, reluctance to ambulate, and prolonged hospitalization/recovery.

Preoperative thoracic radiographic findings in dogs presenting for gastric dilatation-volvulus (2000-2010): 101 cases.

OBJECTIVE: To identify the incidence of clinically significant findings on preoperative thoracic radiographs in dogs with gastric dilatation-volvulus (GDV) and to determine if those findings are associated with survival. DESIGN: Retrospective study from 2000 to 2010. SETTING: Urban university small animal teaching hospital. ANIMALS: One hundred and one dogs diagnosed with GDV that had thoracic radiographs obtained preoperatively, and medical records available with the following information available: signalment, time of presentation, respiratory status, plasma lactate, presence of cardiac arrhythmias, reason for thoracic radiographs, radiographic findings, and outcome. INTERVENTIONS: None. RESULTS: Findings on preoperative thoracic radiographs included small vena cava (40%), esophageal dilation (39%), microcardia (34%), aspiration pneumonia (14%), cardiomegaly (5%), pulmonary nodule (4%), pulmonary edema (2%), sternal lymphadenopathy (1%), and pulmonary bullae (1%). Eighty-four percent of dogs (85 out of 101) survived to discharge. Dogs without cardiomegaly on presenting thoracic radiographs had a 10.2 greater odds of surviving to discharge. CONCLUSIONS: The most common findings on preoperative thoracic radiographs include esophageal dilation, microcardia, and a small vena cava while the incidence of pulmonary nodules was low. A negative association between survival and presence of cardiomegaly on preoperative thoracic radiographs in dogs with GDV supports the need to obtain these images for prognostic information in spite of the emergency surgical nature of the GDV. The main limitations of this study include the possibilities of type I and type II errors, the retrospective nature of the study, and the lack of well-defined criteria for obtaining thoracic radiographs.

Initial application of reduced port surgery using the single port access technique for laparoscopic canine ovariectomy.

OBJECTIVE: To describe the Single port access (SPA) laparoscopic entry technique for canine ovariectomy (OVE), report complications, and outcomes. STUDY DESIGN: Pilot study. ANIMALS: Intact female dogs (n = 6). METHODS: With owner consent, 6 intact female dogs had SPA laparoscopic OVE. Data, including signalment, surgical time (from incision to completion of closure), size and location of port placement, need for conversion (both to standard multiport laparoscopy and laparotomy), as well as any intraoperative complications including blood loss or tissue injury were recorded. RESULTS: Mean surgical time was 52.5 minutes (range, 45-60 minutes) and mean incision length, 1.8 cm (range, 1.5-2.0 cm). In an 18-kg mix breed dog (dog 3), a "single port rescue" was required and located on midline 2-cm caudal to the umbilicus. Close positioning of the trocars caused instrument interference, limited viewing, and prevented safe ligation of the ovarian vessels vein with a vessel-sealing device. OVE was successfully completed laparoscopically in all dogs. CONCLUSION: The SPA laparoscopic entry technique can be used in dogs, although instrument and camera interference can occur if trocar placement is too consolidated within the initial skin incision.

Intervertebral biomechanics of locking compression plate monocortical fixation of the canine cervical spine.

OBJECTIVE: To evaluate the use of a locking compression plate (LCP) with monocortical screw purchase for stabilization of the canine cervical spine. STUDY DESIGN: Experimental study. ANIMALS: Cadaveric canine cervical spine specimens (n = 7). METHODS: Flexion and extension bending moments were applied to canine cadaveric specimens (C3-C6) in 4-point bending, before and after creation of a ventral slot at C4-C5, and after fixation with a 5 hole, 3.5 mm LCP with monocortical screw placement. Screw placement and penetration into the vertebral canal were determined by radiography. Range of motion, stiffness, and energy for passive physiologic loads were determined for the C3-C4, C4-C5, and C5-C6 vertebral motion units (VMU). Monotonic failure properties were determined for cervical extension. Effects of treatments on biomechanical variables were assessed using repeated measures analysis of variance and least square means (P ≤ .05). RESULTS: The ventral slot procedure increased range of motion at the treated VMU. Plate fixation decreased range of motion, increased stiffness, and decreased energy at the treated VMU. No changes were observed at adjacent VMUs. None of the screws penetrated the vertebral canal. Mean (± SD) yield bending moment of plate stabilized, slotted spines was 15.6 ± 4.6 N m. CONCLUSION: LCP fixation with monocortical screws stabilized the canine cervical spine.

Effect of positioning, scan plane, and arthrography on visibility of periarticular canine shoulder soft tissue structures on magnetic resonance images.

This study was performed to determine the effect of shoulder extension and flexion, imaging plane, and intraarticular paramagnetic contrast medium administration on the visibility of soft tissue structures surrounding the canine shoulder joint using magnetic resonance (MR) imaging. Eight dogs without shoulder disease were imaged using a 1.5 T MR scanner. In all dogs, T1- and T2-weighted spin-echo sequences in sagittal, transverse, and dorsal planes, and a sagittal short tau inversion recovery (STIR) sequence were acquired with the shoulder joint in extension. In five dogs, postintravenous contrast medium T1-weighted images were obtained and in five dogs, MR arthrography was performed in flexion and extension. Each specific soft tissue structure was assigned a visual assessment score of 0-3 and descriptive statistics were calculated. The biceps brachii, supraspinatus, and teres minor muscles and tendons, and the biceps tendon sheath were best seen in the sagittal and transverse planes. The infraspinatus was well-visualized in all planes, the subscapularis was best seen in the transverse and dorsal planes, and the capsuloligmentous complexes were best seen in the transverse and dorsal planes. Limb extension improved conspicuousness of the medial capsuloligamentous stuctures. Arthrography resulted in greater conspicuousness of the biceps brachii tendon, biceps tendon sheath, infraspinatus, supraspinatus, subscapularis, medial joint capsule, medial glenohumeral ligament, and the lateral joint capsule-glenohumeral ligament complex. The major periarticular anatomic structures of the normal canine shoulder were consistently identified using the protocols described in this investigation, but arthrography with the joint in extension resulted in the best visualization of all structures.

Effects of zoledronate on markers of bone metabolism and subchondral bone mineral density in dogs with experimentally induced cruciate-deficient osteoarthritis.

OBJECTIVE: To evaluate effects of zoledronate on markers of bone metabolism in dogs after transection of the cranial cruciate ligament (CrCL). ANIMALS: 21 adult dogs. PROCEDURE: Unilateral CrCL transection was performed arthroscopically. Dogs were allocated to 3 groups (control group, low-dose zoledronate [10 microg/kg, SC, q 90 d for 12 months], and high-dose zoledronate [25 microg/kg, SC, q 90 d for 12 months]). Serum osteocalcin (OC), serum bone-specific alkaline phosphatase (BAP), and urine pyridinoline and deoxypyridinoline concentrations were measured at 0, 1, 3, 6, 9, and 12 months after surgery. Bone mineral density (BMD) was determined in the distal portion of the femur and proximal portion of the tibia via computed tomography at each time point. Data were analyzed by a repeated-measures ANOVA. RESULTS: oledronate inhibited OC in the high-dose group at 9 and 12 months and at 12 months in the low-dose group, compared with the control group. High-dose zoledronate decreased BAP concentrations 3 and 9 months after surgery. In the control group, BMD was decreased in the femoral condyle and caudal tibial plateau. Zoledronate prevented significant BMD decreases starting 1 month after transection, compared with control dogs. In the caudomedial aspect of the tibial plateau, both zoledronate groups had significant increases in BMD after 3 months, compared with control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Zoledronate may reduce subchondral bone loss and effect markers of bone metabolism in dogs with experimentally induced instability of the stifle joint and subsequent development of osteoarthritis.

In vivo effects of tepoxalin, an inhibitor of cyclooxygenase and lipoxygenase, on prostanoid and leukotriene production in dogs with chronic osteoarthritis.

OBJECTIVE: To evaluate in vivo effects of tepoxalin, an inhibitor of cyclooxygenase (COX) and lipoxygenase (LOX), on prostaglandin (PG) and leukotriene production in osteoarthritic dogs. ANIMALS: 7 mixed-breed adult dogs with chronic unilateral arthritis of a stifle joint. PROCEDURE: Dogs were treated in accordance with a randomized 3-way crossover design. Each dog received an inert substance, meloxicam, or tepoxalin for 10 days. On day 0 (baseline), 3, and 10, dogs were anesthetized and samples of blood, stifle joint synovial fluid, and gastric mucosa were collected. Concentrations of PGE2 were measured in synovial fluid and after lipopolysaccharide stimulation of whole blood; PGE1 and PGE2 synthesis was measured in gastric mucosa. Thromboxane B2 (TxB2) concentration was measured in whole blood. Leukotriene B4 (LTB4) concentration was determined in gastric mucosa and in whole blood after ex vivo stimulation with a calcium ionophore. RESULTS: Tepoxalin significantly decreased LTB4 concentrations in the blood and gastric mucosa at day 10 and TxB2 concentrations in the blood and PGE2 in the gastric mucosa and synovial fluid at days 3 and 10, compared with baseline values. Meloxicam significantly decreased PGE2 concentrations in the blood at days 3 and 10 and synovial fluid at day 3. Meloxicam also decreased PGE1 and PGE2 synthesis in the gastric mucosa at day 3. Meloxicam did not affect LTB4 synthesis in the blood or LTB4 concentrations in the gastric mucosa. CONCLUSIONS AND CLINICAL RELEVANCE: Tepoxalin has in vivo inhibitory activity against COX-1, COX-2, and 5-LOX in dogs at the current approved recommended dosage.