Quantification of the Field of View for Standard Lateral Arthroscopy of the Canine Shoulder.

OBJECTIVE: The aim of this study was to define the extent of the biceps tendon, subscapularis tendon, and cranial border of the medial glenohumeral ligament within the field of view during standard lateral shoulder arthroscopy in the dog. We also examine the effect of joint flexion on the field of view of the biceps tendon. STUDY DESIGN: This was a cadaveric study using 21 shoulders of large breed dogs. Each shoulder was explored with a 30-degree arthroscope using standard lateral ports. For each supporting structure, the margins within the arthroscopic field of view were marked with ink. In 11 shoulders, the distal margin of the biceps tendon was identified and marked first with the limb at a standing angle and then in flexion. The margins of the cranial border of the medial glenohumeral ligament were marked at the standing angle. In 10 additional shoulders, the margins of the subscapularis tendon were evaluated. Each joint was fully dissected and the portion of each stabilizing structure within the field of view was quantified. RESULTS: Fifty-eight percent of the cranial border of the medial glenohumeral ligament was within the arthroscopic view. At a standing angle, 48% of the intra-articular length of the biceps tendon was within the arthroscopic view, compared to 63% with the limb flexed. Twenty percent of the subscapularis tendon was within the arthroscopic view. CONCLUSION: A significant portion of the biceps tendon and medial stabilizing structures of the canine shoulder are outside the field of view of arthroscopy through a standard lateral approach. The limitations of the arthroscopic field of view should be appreciated when evaluating the shoulder.

Accuracy of 3 Tesla magnetic resonance imaging using detection of fiber loss and a visual analog scale for diagnosing partial and complete cranial cruciate ligament ruptures in dogs.

Canine cranial cruciate ligament rupture is often bilateral and asymmetrical, ranging from partial to complete rupture. The purpose of our diagnostic accuracy study was to assess the accuracy of 3 Tesla magnetic resonance imaging (MRI) detection of fiber loss and use of a visual analog scale in the diagnosis of complete versus partial cranial cruciate ligament rupture in 28 clinical dogs with unilateral complete rupture and contralateral partial rupture. Three Tesla MRI was performed on 56 stifles using sagittal sequences (T2-weighted fast spin echo with fat saturation, proton density fast spin echo, and T2-weighted 3D fast spin echo CUBE). Two MRI observers assessed the cranial cruciate ligament for fiber loss and completed a visual analog scale. The MRI data were compared to arthroscopy and clinical status. Accuracy classifying partial or complete rupture was assessed using receiver operating characteristic analysis. Compared to arthroscopy, for complete cranial cruciate ligament rupture, sensitivity, specificity, and accuracy of MRI detection of fiber loss were 0.78, 0.50-0.60, and 0.68-0.71, respectively, and, for partial tears, specificity was 1.00. An MRI visual analog scale score ≥79 was indicative of complete cranial cruciate ligament rupture (sensitivity 0.72-0.94 and specificity 0.71-0.84). Using a visual analog scale cut-point ≥79, observers achieved good accuracy discriminating clinical status of partial or complete cranial cruciate ligament rupture (area under the curve 0.87-0.93). MRI evaluation for fiber loss and use of a visual analog scale are specific in stifles with clinically stable partial cranial cruciate ligament rupture. In stifles with clinically unstable complete cranial cruciate ligament rupture, both MRI tests are sensitive though not specific compared to arthroscopy. As a diagnostic imaging method, MRI may help guide treatment in patients with cranial cruciate ligament damage, particularly for stable partial rupture.

Radiographic and magnetic resonance imaging predicts severity of cruciate ligament fiber damage and synovitis in dogs with cranial cruciate ligament rupture.

Cruciate ligament rupture (CR) and associated osteoarthritis (OA) is a common condition in dogs. Dogs frequently develop a second contralateral CR. This study tested the hypothesis that the degree of stifle synovitis and cranial cruciate ligament (CrCL) matrix damage in dogs with CR is correlated with non-invasive diagnostic tests, including magnetic resonance (MR) imaging. We conducted a prospective cohort study of 29 client-owned dogs with an unstable stifle due to complete CR and stable contralateral stifle with partial CR. We evaluated correlation of stifle synovitis and CrCL fiber damage with diagnostic tests including bilateral stifle radiographs, 3.0 Tesla MR imaging, and bilateral stifle arthroscopy. Histologic grading and immunohistochemical staining for CD3+ T lymphocytes, TRAP+ activated macrophages and Factor VIII+ blood vessels in bilateral stifle synovial biopsies were also performed. Serum and synovial fluid concentrations of C-reactive protein (CRP) and carboxy-terminal telopeptide of type I collagen (ICTP), and synovial total nucleated cell count were determined. Synovitis was increased in complete CR stifles relative to partial CR stifles (P<0.0001), although total nucleated cell count in synovial fluid was increased in partial CR stifles (P<0.01). In partial CR stifles, we found that 3D Fast Spin Echo Cube CrCL signal intensity was correlated with histologic synovitis (SR = 0.50, P<0.01) and that radiographic OA was correlated with CrCL fiber damage assessed arthroscopically (SR = 0.61, P<0.001). Taken together, results of this study show that clinical diagnostic tests predict severity of stifle synovitis and cruciate ligament matrix damage in stable partial CR stifles. These data support use of client-owned dogs with unilateral complete CR and contralateral partial CR as a clinical trial model for investigation of disease-modifying therapy for partial CR.

Autologous Bone Marrow-Derived Mesenchymal Stem Cells Modulate Molecular Markers of Inflammation in Dogs with Cruciate Ligament Rupture.

Mid-substance rupture of the canine cranial cruciate ligament rupture (CR) and associated stifle osteoarthritis (OA) is an important veterinary health problem. CR causes stifle joint instability and contralateral CR often develops. The dog is an important model for human anterior cruciate ligament (ACL) rupture, where rupture of graft repair or the contralateral ACL is also common. This suggests that both genetic and environmental factors may increase ligament rupture risk. We investigated use of bone marrow-derived mesenchymal stem cells (BM-MSCs) to reduce systemic and stifle joint inflammatory responses in dogs with CR. Twelve dogs with unilateral CR and contralateral stable partial CR were enrolled prospectively. BM-MSCs were collected during surgical treatment of the unstable CR stifle and culture-expanded. BM-MSCs were subsequently injected at a dose of 2x106 BM-MSCs/kg intravenously and 5x106 BM-MSCs by intra-articular injection of the partial CR stifle. Blood (entry, 4 and 8 weeks) and stifle synovial fluid (entry and 8 weeks) were obtained after BM-MSC injection. No adverse events after BM-MSC treatment were detected. Circulating CD8+ T lymphocytes were lower after BM-MSC injection. Serum C-reactive protein (CRP) was decreased at 4 weeks and serum CXCL8 was increased at 8 weeks. Synovial CRP in the complete CR stifle was decreased at 8 weeks. Synovial IFNγ was also lower in both stifles after BM-MSC injection. Synovial/serum CRP ratio at diagnosis in the partial CR stifle was significantly correlated with development of a second CR. Systemic and intra-articular injection of autologous BM-MSCs in dogs with partial CR suppresses systemic and stifle joint inflammation, including CRP concentrations. Intra-articular injection of autologous BM-MSCs had profound effects on the correlation and conditional dependencies of cytokines using causal networks. Such treatment effects could ameliorate risk of a second CR by modifying the stifle joint inflammatory response associated with cranial cruciate ligament matrix degeneration or damage.

Metallosis with pseudotumour formation: Long-term complication following cementless total hip replacement in a dog.

CASE DESCRIPTION: A 10-year-old female Belgian Teruven dog was presented to our clinic for total hip revision following a diagnosis of implant (cup) failure with metallosis and abdominal pseudotumour formation. The patient had a cementless metal-on-polyethylene total hip replacement performed nine years prior to presentation. CLINICAL FINDINGS: The clinical findings, including pseudotumour formation locally and at sites distant from the implant and pain associated with the joint replacement, were similar to those described in human patients with this condition. Histopathological, surgical, and radiographic findings additionally supported the diagnosis of metallosis and pseudotumour formation. TREATMENT AND OUTCOME: Distant site pseudotumours were surgically removed and the total hip replacement was explanted due to poor bone quality. The patient recovered uneventfully and has since resumed normal activity. CONCLUSION: In veterinary patients with metal-on-polyethylene total hip implants, cup failure leading to metallosis and pseudotumour formation should be considered as a potential cause of ipsilateral hindlimb lameness, intra-pelvic abdominal tumours, or a combination of both. These clinical findings may occur years after total hip replacement surgery.

Arthroscopic assessment of stifle synovitis in dogs with cranial cruciate ligament rupture.

Cranial cruciate ligament rupture (CR) is a degenerative condition in dogs that typically has a non-contact mechanism. Subsequent contralateral rupture often develops in dogs with unilateral CR. Synovitis severity is an important factor that promotes ligament degradation. Consequently, we wished to evaluate the utility of arthroscopy for assessment of stifle synovitis in dogs with CR. Herein, we report results of a prospective study of 27 dogs with unilateral CR and bilateral radiographic osteoarthritis. Arthroscopic images and synovial biopsies from the lateral and medial joint pouches were obtained bilaterally and graded for synovial hypertrophy, vascularity, and synovitis. Synovial tartrate-resistant acid phosphatase-positive (TRAP+) macrophages, CD3(+) T lymphocytes, Factor VIII+ blood vessels, and synovial intima thickness were quantified histologically and related to arthroscopic observations. Risk of subsequent contralateral CR was examined using survival analysis. We found that arthroscopic scores were increased in the index stifle, compared with the contralateral stifle (p<0.05). Numbers of CD3+ T lymphocytes (SR = 0.50, p<0.05) and TRAP+ cells in joint pouches (SR = 0.59, p<0.01) were correlated between joint pairs. Arthroscopic grading of vascularity and synovitis was correlated with number density of Factor VIII+ vessels (SR>0.34, p<0.05). Arthroscopic grading of villus hypertrophy correlated with numbers of CD3(+) T lymphocytes (SR = 0.34, p<0.05). Synovial intima thickness was correlated with arthroscopic hypertrophy, vascularity, and synovitis (SR>0.31, p<0.05). Strong intra-observer and moderate inter-observer agreement for arthroscopic scoring was found. Dog age and arthroscopic vascularity significantly influenced risk of contralateral CR over time. We conclude that arthroscopic grading of synovitis is a precise tool that correlates with histologic synovitis. Arthroscopy is useful for assessment of stifle synovitis in client-owned dogs, and could be used in longitudinal clinical trials to monitor synovial responses to disease-modifying therapy.

Students' perception of case-based continuous assessment and multiple-choice assessment in a small animal surgery course for veterinary medical students.

OBJECTIVE: To determine the relationship between students' perceptions of 2 assessment methods and academic performance. STUDY DESIGN: A 2-year prospective survey study in a 4-year Doctor of Veterinary Medicine (DVM) curriculum. SAMPLE POPULATION: Year 3 DVM students (n = 44). METHODS: An assessment of learning gain questionnaire was used to investigate students' perceptions regarding multiple-choice examination (MCE) versus take-home case-based continuous assessment (CA) in a 3rd year small animal surgery lecture course. Academic performance and student assessment of learning gain in the 2 course components were compared. Relationships between student perceptions and academic performance were examined. A follow-up survey was conducted during clinical rotations in 4th year to determine change in student perceptions over time. RESULTS: Academic performance in 3rd year was significantly enhanced by use of CA, particularly for students with weaker grades. Academic performance in 4th year clinical rotations was not closely related to 3rd year performance. Many students preferred an instructional approach with provision of comprehensive notes and assessment with multiple-choice questions based on the notes. However, students recognized that feedback on work submitted for CA grading significantly facilitated learning. Student assessment of learning gain was correlated with academic performance in the 3rd year course component examined by CA, but not the component assessed using MCE. CONCLUSION: Our data suggest that perceptions of learning gain, academic accomplishment, and clinical performance in 4th year are weakly correlated. Teachers should better explain to veterinary students that learning to be a clinician is more than replication of knowledge.

Effects of observer on the diagnostic accuracy of low-field MRI for detecting canine meniscal tears.

Low-field MRI (lfMRI) has become increasingly accepted as a method for diagnosing canine meniscal tears in clinical practice. However, observer effects on diagnostic accuracy have not been previously reported. In this study, 50 consecutive stifle joints with clinical and radiologic evidence of cranial cruciate ligament insufficiency were investigated by lfMRI and arthroscopy. Fifteen observers who had varying levels of experience and who were unaware of arthroscopic findings independently reviewed lfMRI studies and recorded whether lateral and medial meniscal tears were present. Diagnostic accuracy (sensitivity, specificity, positive (PPV) and negative predictive value (NPV)) was determined for each observer and median values were calculated for all observers, using arthroscopy as the reference standard. Interrater agreement was determined based on intraclass correlation coefficient (ICC) analysis. Observer level of experience was compared with diagnostic sensitivity and specificity using correlation analysis. Based on pooled data for all observers, median sensitivity, specificity, PPV, and NPV for lfMRI diagnosis of lateral meniscal tears were 0.00, 0.94, 0.05, and 0.94, respectively. Median sensitivity, specificity, PPV, and NPV for medial meniscal tears were 0.74, 0.89, 0.83, and 0.79, respectively. Interrater agreement for all menisci was fair (0.51). Menisci were less consistently scored as having no tears (ICC = 0.13) than those scored as having tears (ICC = 0.50). No significant correlations between observer experience and diagnostic sensitivity/specificity were identified. Findings indicated that the accuracy of lfMRI for diagnosing canine meniscal tears was poor to fair and observer-dependent. Future studies are needed to develop standardized and widely accepted lfMRI criteria for diagnosing meniscal tears.

Lymphocyte populations in joint tissues from dogs with inflammatory stifle arthritis and associated degenerative cranial cruciate ligament rupture.

OBJECTIVE: To evaluate lymphocyte populations in stifle synovium and synovial fluid of dogs with degenerative cranial cruciate ligament rupture (CCLR). STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs (n=25) with stifle arthritis and CCLR, 7 dogs with arthritis associated with cartilage degeneration (osteoarthritis [OA]), and 12 healthy Beagle dogs with intact CCL. METHODS: Arthritis was graded radiographically in CCLR dogs. After collection of joint tissues, mononuclear cells were isolated and subsequently analyzed using flow cytometry for expression of CD3, CD4, CD8, and CD21. RESULTS: The proportions of CD4(+) T helper lymphocytes, CD8(+) cytotoxic T lymphocytes, and CD3(+) CD4(-) CD8(-) T lymphocytes were increased in synovium from dogs with CCLR compared with synovium from healthy Beagle dogs (P<.05). The proportion of CD3(+) CD4(-) CD8(-) T lymphocytes in synovial fluid was increased in dogs with CCLR compared with dogs with OA (P<.05). In dogs with CCLR, the proportion of CD3(+) CD4(-) CD8(-) T lymphocytes in synovial fluid was inversely correlated with radiographic arthritis (S(R) =-0.68, P<.005). CONCLUSION: Lymphocytic inflammation of stifle synovium and synovial fluid is an important feature of the CCLR arthropathy. Lymphocyte populations include T lymphocytes expressing CD4 and CD8, and CD3(+) CD4(-) CD8(-) T lymphocytes. Presence of CD3(+) CD4(-) CD8(-) T lymphocytes was associated with development of stifle synovitis. Further work is needed to fully identify the phenotype of these cells.

Synovitis in dogs with stable stifle joints and incipient cranial cruciate ligament rupture: a cross-sectional study.

OBJECTIVE: To evaluate stifle joints of dogs for synovitis, before development of joint instability and cranial cruciate ligament rupture (CrCLR). STUDY DESIGN: Cross-sectional study. ANIMALS: Dogs (n = 16) with CrCLR and stable contralateral stifles; 10 control dogs with intact CrCL. METHODS: Arthritis and tibial translation were graded radiographically. Synovitis severity and cruciate pathology were assessed arthroscopically. Presence of inflammatory cells in synovial membrane biopsies was scored histologically. CrCLR stifle pairs and control stifles were compared. RESULTS: Radiographic evidence of arthritis, cranial tibial translation, and arthroscopic synovitis were increased in unstable stifles, when compared with stable contralateral stifles in CrCLR dogs (P < .05). Arthroscopic synovitis in both joints of CrCLR dogs was increased compared with controls, was correlated with radiographic arthritis (S(R) = 0.71, P < .05), and was present in all stable contralateral stifles. Arthroscopically, 75% of stable stifle joints had CrCL fiber disruption, which correlated with severity of synovitis (S(R) = 0.56, P < .05). Histologic evidence of synovitis was identified in all CrCLR dogs, but was only significantly correlated with arthroscopic observations in stable stifles (r(2) = 0.57, P < .005). CONCLUSION: Synovitis is an early feature of the CrCLR arthropathy in dogs before development of joint instability clinically. Severity of synovitis is correlated with radiographic arthritis in joints with minimal to no clinically detectable CrCL damage.

Effect of rhBMP-2 on tibial plateau fractures in a canine model.

This study was to determine the efficacy of recombinant human bone morphogenetic protien-2 (rhBMP-2)/calcium phosphate matrix (CPX) paste to accelerate healing in a canine articular fracture model with associated subchondral defect. rhBMP-2/CPX (BMP), CPX alone (CPX) or autogenous bone graft (ABG) was administered to a canine articular tibial plateau osteotomy with a subchondral defect in each of 21 female dogs. The unoperated contralateral limbs served as controls. Ground reaction forces, synovial fluid, radiographic changes, mechanical testing, bone density, and histology of bone and synovium were analyzed at 6 weeks after surgery. Radiographic analysis demonstrated that the BMP and CPX groups showed improved bony healing compared to the ABG group at week 6. Histomorphometric analysis demonstrated that the BMP group had significantly increased trabecular bone volume compared to the CPX and ABG groups. Mechanical testing revealed that the BMP group had significantly greater maximum failure loads than the ABG group. Histological analysis demonstrated that the BMP group had significantly less sub-synovial inflammation than CPX group. This study demonstrated that rhBMP-2/CPX accelerated healing of articular fractures with subchondral defect compared to ABG in most of the parameters evaluated, and had less subsynovial inflammation than the CPX alone in a canine model.

Magnetic resonance imaging findings in dogs with confirmed shoulder pathology.

OBJECTIVE: To evaluate the diagnostic potential of magnetic resonance imaging (MRI) compared with a reference standard, arthroscopic and/or open surgery, in dogs with soft tissue shoulder pathology. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=21). METHODS: Magnetic resonance (MR) images were retrospectively evaluated in 21 dogs that had surgically identified soft tissue shoulder pathology. The musculotendinous units of the biceps, infraspinatus, teres minor, supraspinatus, subscapularis, and the medial and lateral glenohumeral ligaments (MGHL and LGHL) were graded as either normal or abnormal. Abnormal structures were further classified as being either inflamed, partially torn, or fully torn. Impingement of the biceps tendon was also evaluated. Results were reported in terms of agreement and concordance between MRI findings and surgical findings. Agreement was defined as the percentage of times MRI findings concurred with surgical findings with respect to a structure being either normal or abnormal. Concordance was defined as the percentage of times MRI concurred with the exact surgically assessed pathology when abnormality was identified. RESULTS: The findings were biceps tendon: 90% agreement with 100% concordance; subscapularis: 95% agreement with 62% concordance; MGHL: 84% agreement with 83% concordance; LGHL: 88% agreement with 100% concordance; infraspinatus: 100% both agreement and concordance; biceps tendon impingement: 90% agreement with 100% concordance. CONCLUSIONS: Soft tissue abnormalities of the canine shoulder were readily identified on preoperative MR images. CLINICAL RELEVANCE: MRI shows great potential as a diagnostic tool in the evaluation of canine shoulder disease.

Detection of DNA from a range of bacterial species in the knee joints of dogs with inflammatory knee arthritis and associated degenerative anterior cruciate ligament rupture.

Mixtures of bacterial nucleic acids can often be detected in synovial joints affected with arthritis. We investigated the potential role of such mixtures of bacterial nucleic acids in the pathogenesis of arthritis in a naturally occurring canine model. Dogs with a common inflammatory knee arthritis in which associated pathological degenerative anterior cruciate ligament (ACL) rupture often develops were studied. Synovial biopsies were obtained from 43 dogs with the naturally occurring ACL rupture arthropathy, 12 dogs with normal knees and intact ACL, and 16 dogs with normal knees and experimentally induced ACL rupture. Using PCR, specimens were tested for Borrelia burgdorferi OspA and p66 gene sequences. Broad-ranging 16S rRNA primers were also used; 'panbacterial' PCR products were cloned and multiple clones were sequenced for bacterial identification. Synovium was also studied histologically. The presence of bacterial DNA within the synovium was significantly associated with the naturally occurring ACL rupture arthropathy (p<0.05); knee joints from 37% of these dogs were PCR-positive. Mixtures of bacterial DNA were common and often included environmental bacteria; predominant organisms included Borrelia burgdorferi and Stenotrophomonas maltophilia. DNA from environmental bacteria was only found in dogs with the naturally occurring ACL rupture arthopathy; joints from 33% of affected dogs contained such bacterial DNA. Synovial inflammation developed in dogs with both naturally occurring and experimentally induced ACL rupture, when compared with intact ACL controls (p<0.01). These results indicate that mixtures of DNA derived from environmental bacteria are commonly found in the knee joint of a naturally occurring canine arthropathy, often in association with a recognized joint pathogen. Our results also suggest that knee instability alone is not responsible for this finding and have led us to hypothesize that mixtures of bacterial DNA are an important causative factor in the pathogenesis of inflammatory arthritis in this canine model.

Magnetic resonance imaging of the canine shoulder: an anatomic study.

OBJECTIVES: To describe the normal anatomy of the soft tissue stabilizing components of the canine shoulder identified by magnetic resonance imaging (MRI) and to evaluate specific acquisition sequences and planes for observing structures of diagnostic interest. STUDY DESIGN: Descriptive study. ANIMAL: Canine cadavers (n=3). METHODS: T1-weighted, proton density fat saturation (PD), and T2(*)-weighted gradient echo (GE) MRI sequences were obtained in the sagittal, transverse, and dorsal planes of the left shoulder of 3 canine cadavers. After imaging, each shoulder was embedded and thin sectioned. The corresponding right shoulder was frozen and thick sectioned. The anatomic structures on the histologic and frozen thick sections were visually correlated with the MR images. RESULTS: The sagittal plane provided a longitudinal view of the bicep, infraspinatus, and supraspinatus tendons. The biceps, supraspinatus, infraspinatus, and subscapularis tendons, and the medial and lateral glenohumeral ligaments were identified in the transverse and dorsal planes. The dorsal plane allowed for the bicep tendon to be evaluated transversely as it passed over the humeral head. The GE sequence was more useful in identifying tendons and ligaments. The PD sequence was more helpful in identifying fluid accumulations in the joint and around tendons. CONCLUSIONS: The tendinous and ligamentous structures that stabilize the canine shoulder joint can be readily identified with MRI. CLINICAL RELEVANCE: MRI has the potential to be a useful tool in the diagnosis of canine soft tissue shoulder injuries.