Prevalence of osteoarthritis in the shoulder, elbow, hip and stifle joints of dogs older than 8 years.

Osteoarthritis is one of the most common diseases in veterinary medicine. There are various causes for joints developing OA, with some of them being well investigated, while others are still a matter of speculation. In this retrospective study we examined the prevalence of OA in the shoulder, elbow, hip and stifle joints in a clinic population of dogs older than 8 years, which were presented mostly due to orthopaedic complaints. Dogs were included in the study if one or more of the aforementioned joints was included in the radiographs. Radiographs were reviewed by three different observers and graded by severity. Prevalence of OA was 39.2%, 57.4%, 35.9% and 36.4% for the shoulder, elbow, hip and stifle, respectively. There was no correlation between higher grades of OA and weight as well as age, but significantly higher prevalence of OA in heavier groups when grouped for weight. Sex and castration status did not affect presence of OA. As most of the examined joints were free of OA, radiographic findings suggestive of OA should not be considered normal in senescent dogs.

Radiographic analysis in Thoroughbreds reveals morphological changes in healthy maturing stifle joints and possible association between subchondral lesions and femoral condyle width.

OBJECTIVE: Assess femorotibial features in foals with and without medial femoral condyle (MFC) subchondral radiolucencies (SR+ and SR-). METHODS: 3 independent, sequential radiographic studies were performed. Study 1 retrospectively measured femorotibial morphological parameters in repository radiographs (SR- and SR+). Study 2 qualitatively compared drawings of intercondylar notch shape in postmortem radiographs (SR-). Study 3 prospectively measured femorotibial parameters in 1-month-old foals (SR-). In studies 1 and 3, 13 morphologic parameters were measured. Limb directional asymmetry was assessed in 2 age groups (< 7 or ≥ 7 months). RESULTS: Study 1 (SR- group; n = 183 radiographs) showed increased femoral measurements with maturation, except the distal femoral intercondylar notch width (FINwal), which decreased. In contrast, in SR+ stifles (53 radiographs), 3 femoral parameters (MFC width [MFCwpf], MFC height, or FINwal) showed no changes. Tibial plateau width alone increased with maturation in both groups. Interobserver reliability was good to excellent. Study 2 (n = 53 radiographs) confirmed a distal FINw decrease in SR- foals. In study 1, left SR- stifles in greater than or equal to 7-month-old fillies had significantly larger femoral bicondylar width and FINw, while right SR+ stifles in fillies greater than or equal to 7 months had a significantly larger MFCw. In study 3 of 1-month-old foals (n = 94 SR- radiographs), the MFCw, femoral condyle bicondylar width, and lateral femoral condyle height were all greater on the left, whereas the intercondylar intereminence space width was larger on the right. CLINICAL RELEVANCE: In SR+ stifles, the distal femur exhibited divergent maturation, indicating a wider MFC in the right stifle in older foals. As SR lesions are more common on the right, this suggests a potential association with MFC morphology.

An Optimization Approach for Creating Application-specific Ultrasound Speckle Tracking Algorithms.

OBJECTIVE: Ultrasound speckle tracking enables in vivo measurement of soft tissue deformation or strain, providing a non-invasive diagnostic tool to quantify tissue health. However, adoption into new fields is challenging since algorithms need to be tuned with gold-standard reference data that are expensive or impractical to acquire. Here, we present a novel optimization approach that only requires repeated measurements, which can be acquired for new applications where reference data might not be readily available or difficult to get hold of. METHODS: Soft tissue motion was captured using ultrasound for the medial collateral ligament (MCL) of three quasi-statically loaded porcine stifle joints, and medial ligamentous structures of a dynamically loaded human cadaveric knee joint. Using a training subset, custom speckle tracking algorithms were created for the porcine and human ligaments using surrogate optimization, which aimed to maximize repeatability by minimizing the normalized standard deviation of calculated strain maps for repeat measurements. An unseen test subset was then used to validate the tuned algorithms by comparing the ultrasound strains to digital image correlation (DIC) surface strains (porcine specimens) and length change values of the optically tracked ligament attachments (human specimens). RESULTS: After 1500 iterations, the optimization routine based on the porcine and human training data converged to similar values of normalized standard deviations of repeat strain maps (porcine: 0.19, human: 0.26). Ultrasound strains calculated for the independent test sets using the tuned algorithms closely matched the DIC measurements for the porcine quasi-static measurements (R > 0.99, RMSE < 0.59%) and the length change between the tracked ligament attachments for the dynamic human dataset (RMSE < 6.28%). Furthermore, strains in the medial ligamentous structures of the human specimen during flexion showed a strong correlation with anterior/posterior position on the ligaments (R > 0.91). CONCLUSION: Adjusting ultrasound speckle tracking algorithms using an optimization routine based on repeatability led to robust and reliable results with low RMSE for the medial ligamentous structures of the knee. This tool may be equally beneficial in other soft-tissue displacement or strain measurement applications and can assist in the development of novel ultrasonic diagnostic tools to assess soft tissue biomechanics.

Estimation of footprints of the canine stifle ligaments using deformable shape templates of bones.

Knowledge regarding the ligament footprints in the canine stifle is essential for biomechanical modeling of the joint and patient-specific surgical planning for anatomical ligament reconstruction. The present study aimed to establish and evaluate deformable shape templates (DSTs) of the femur and tibia with footprints of the cruciate and collateral ligaments embedded for the noninvasive estimation of ligament footprint positions. To this end, a data set of computed tomography (CT)-derived surface models of the femur and tibia were established and used to build statistical shape models (SSMs). The contours of the stifle ligaments were obtained from CT scans of 27 hindlimb specimens with radio-opaque markings on the ligament footprints. The DST, constructed by embedding averaged footprint contours into the SSM, was used to estimate subject-specific ligament footprints in a leave-one-out cross-validation framework. The DST predictions were compared with those derived from radio-opaque-marked footprints. The results showed that the averaged Euclidean distances between the estimated and reference footprint centroids were less than 1.2 mm for the cruciate ligaments and 2.0 mm for the collateral ligaments. The DST appeared to provide a feasible alternative approach for noninvasively estimating the footprints of the stifle ligaments in vivo.

Ultrashort Echo Time Quantitative Magnetic Resonance Imaging of the Cruciate Ligaments in Normal Beagles.

OBJECTIVE: The aim of this study was to provide normative ultrashort echo time magnetic resonance imaging (UTE MRI) data of the patellar ligament (PL), cranial cruciate ligament (CrCL) and caudal cruciate ligament (CdCL) in non-lame Beagles. STUDY DESIGN: Eight stifles from four subjects obtained immediately postmortem were imaged using UTE MRI in the true sagittal plane. Regions of interest were drawn manually and the total (T2*), short T2* (T2*S) and long T2* (T2*L) values of the signal decay were calculated to evaluate the bound and free water components of the tendon. The T2*S, T2*L and T2* values were compared between the PL, CrCL and CdCL RESULTS: The mean and standard deviation of T2*S, T2*L and T2* were as follows: 0.54 ± 0.13, 4.65 ± 1.08 and 8.35 ± 0.82 ms for the PL; 0.46 ± 0.14, 5.99 ± 0.52 and 8.88 ± 0.4 ms for the CrCL and 0.41 ± 0.13, 7.06 ± 0.57 and 9.26 ± 0.18 ms for the CdCL. Significant differences were found between the T2*L component of the PL and each CrCL/CdCL and a smaller difference was noted between the T2*L of the CrCL and CdCL (p = 0.05). No difference of the T2*S value was found between any of the ligaments. CONCLUSION: Establishing normative UTE data of the canine stifle is valuable for comparison in future studies in which normal and damaged ligaments may be evaluated, particularly in those affected limbs in which no instability is identified on physical examination in which normal and damaged ligaments may be evaluated.

Computed tomographic imaging and surgical management of distal insertional avulsion fragments of the caudal cruciate ligament in four horses.

OBJECTIVE: To describe cases with caudal cruciate ligament (CdCL) avulsion fragments diagnosed based on computed tomography (CT) examination and report on arthroscopic fragment removal. ANIMALS: Four Warmblood horses with hindlimb lameness and osseous fragments located in the caudal medial femorotibial joint (mFTJ). STUDY DESIGN: Short case series. METHODS: CT and arthroscopic evaluation of the caudal mFTJ were performed. The caudal mFTJ and the insertion of the CdCL on the tibia were assessed and removal of the avulsion fragments was attempted in three horses using a cranial intercondylar approach. RESULTS: The fragment was not accessible via caudomedial approaches in one horse. A cranial intercondylar approach was used in three horses, allowing removal of the intra-articular fragment in two horses, and removal of two-thirds of the proximal fragment in the last horse. Acute, profuse, arterial bleeding occurred in this horse during surgery with transient postoperative soft tissue swelling. Comorbidities included medial femoral condyle cartilage defects (3), cranial cruciate ligament lesions (2), and medial collateral ligament lesions (2). Horses were followed up for 16 months (median, range 11-28 months), at which point all were back in ridden exercise; owners' satisfaction was good. CONCLUSION: CT examination confirmed the diagnosis and allowed evaluation of the stifle joint for comorbidities. A cranial intercondylar arthroscopic approach facilitated the removal of CdCL insertional avulsion fragments, although not always complete. CLINICAL SIGNIFICANCE: A cranial intercondylar approach can allow access to CdCL avulsion fragments, but complications and incomplete removal remain possible.

Relationship between the degree of stifle flexion and the proximal patellofemoral angle in the sagittal plane: A radiographic study.

The objective of this study was to evaluate the position of the patella in relation to the proximal femoral axis in the sagittal plane and to assess its reliability as a surgical landmark for femoral component placement in canine hip replacement. The relationship between the patella and the proximal femoral axis was assessed by defining the proximal patellofemoral angle in medio-lateral radiographic projections with 3 different stifle angles (full flexion, 90°, full extension) in medium to large breed skeletally mature dogs (N = 14). Proximal patellofemoral angle measurements were compared between the 3 different groups of stifle position using ANOVA for statistical analysis. The mean proximal patellofemoral angle measurements were -7.4° (± 1.3°) in the flexion group, -1.6° (± 1.5°) in the 90° group, and 2.1° (± 1.8°) in the extension group. Statistically significant differences were seen in the proximal patellofemoral angle between groups (P ≤ 0.001). These results confirm that position of the patella related to the proximal femoral axis differs depending on the degree of stifle flexion. The degree of stifle flexion should be considered in the preoperative planning and intraoperatively when using the patella as a surgical landmark in the sagittal plane for femoral canal broaching in canine total hip replacement.

L'objectif de cette étude était d'évaluer la position de la rotule par rapport à l'axe fémoral proximal dans le plan sagittal et d'évaluer sa fiabilité en tant que repère chirurgical pour le placement du composant fémoral dans le remplacement de la hanche canine. La relation entre la rotule et l'axe fémoral proximal a été évaluée en définissant l'angle fémoro-patellaire proximal dans des projections radiographiques médio-latérales avec trois angles de grasset différents (flexion complète, 90°, extension complète) chez des chiens de race moyenne à grande (N = 14). Les mesures de l'angle fémoro-patellaire proximal ont été comparées entre les trois groupes différents de position de grasset en utilisant l'ANOVA pour l'analyse statistique. Les mesures moyennes de l'angle fémoro-patellaire proximal étaient de −7,4° (± 1,3°) dans le groupe flexion, −1,6° (± 1,5°) dans le groupe 90° et 2,1° (± 1,8°) dans le groupe extension. Des différences statistiquement significatives ont été observées dans l'angle fémoro-patellaire proximal entre les groupes (P ≤ 0,001). Ces résultats confirment que la position de la rotule par rapport à l'axe fémoral proximal diffère selon le degré de flexion du grasset. Le degré de flexion du grasset doit être pris en compte dans la planification préopératoire et peropératoire lors de l'utilisation de la rotule comme repère chirurgical dans le plan sagittal pour la présentation du canal fémoral dans le cadre d'une arthroplastie totale de hanche canine.(Traduit par Docteur Serge Messier).

Evaluation of proximodistal patellar alignment in small breed dogs with or without patellar luxation using the Insall-Salvati, Caton-Deschamps, and Blackburne-Peel indices.

Background: Patellar luxation in dogs is thought to be related to proximally (patella alta) or distally (patella baja) positioned patella in the femoral trochlea. Aim: The aim of the present study was to calculate and compare the values of Insall-Salvati (ISI), Caton-Deschamps (CDI), and Blackburne-Peel indices (BPI) in orthopedically healthy dogs and dogs with various grades of medial patellar luxation (MPL) from small breeds on mediolateral radiographs. Methods: The study included 87 dogs (138 stifles) from four breeds (Mini-Pinschers, Pomeranians, Chihuahuas, and Yorkshire terriers). Seventy joints (53 dogs) were diagnosed with various grades of MPL and another 68 joints from 34 dogs, free of orthopedic or neurological disorders, were used as controls. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic value of the three indices. Results: The CDI and BPI showed no significant difference between healthy and MPL joints. The ROC analysis showed that all three studied indices of proximodistal patellar position had poor diagnostic values with low sensitivity and specificity of respective cutoff values. Conclusion: In dogs from the studied four small breeds, the proximodistal ISI, CDI, and BPI patellar indices could not discriminate reliably between healthy stifle joints and joints with MPL.

Cranial tibial translation measurements for radiographic diagnosis of cranial cruciate ligament rupture in dogs.

OBJECTIVE: To assess the effect of tibial compression on radiographic cranial tibial translation measurements in healthy dogs and those with cranial cruciate ligament (CCL) rupture and establish specific criteria for the radiographic diagnosis of CCL rupture. ANIMALS: 60 dogs. PROCEDURES: Dogs were divided into 3 groups with 20 dogs each: group 1, healthy adult dogs; group 2, adult dogs with CCL rupture; and group 3, healthy young dogs. For each dog, 2 images of the stifle joint in mediolateral projection were taken, of which 1 was conventional and 1 was under tibial compression. Variables were measured in each radiographic projection: the patellar ligament angle, the patellar ligament insertion angle, the angle of tibial translation measured by 2 different methods, and the linear distance between the points of CCL origin and insertion (DPOI). Additionally, a novel variable, DPOI ratio, was evaluated. RESULTS: Regarding radiographic positioning, tibial compression significantly changed most of the variables in the within-group comparison. The variable DPOI were not different with and without tibial compression in the group of healthy adult dogs but were different for dogs with CCL rupture. Thus, these are important parameters in the diagnosis of CCL rupture. In the analysis of a novel variable, DPOI ratio, dogs with CCL rupture could be distinguished from healthy dogs at a high level of specificity and sensitivity. CLINICAL RELEVANCE: DPOI ratio values above 1.18 were consistently indicative of CCL rupture, thus allowing for a precise radiographic diagnosis of the condition.

Examination of Proximodistal Patellar Position in Dogs with the Stifle at Full Extension.

OBJECTIVE: The aim of this study was to determine the factors related to functional patella alta, with which the proximodistal patellar position exceeds the reference range of healthy small dogs proximally when the stifle is at full extension. STUDY DESIGN: Mediolateral-view radiographs of dogs weighing less than 15 kg were obtained and classified into the medial patellar luxation (MPL) and control groups. The reference range of the proximodistal patellar position was determined from the control group. In both groups, a patellar position exceeding this reference range proximally was considered functional patella alta. Multiple logistic regression analysis was performed to examine the factors related to functional patella alta. A receiver operating characteristic (ROC) curve was made for each factor. RESULTS: Overall, radiographs of 127 stifles of 75 dogs were obtained. Eleven stifles in the MPL group and one stifle in the control group were determined to be functional patella alta. The factors associated with functional patella alta included a greater full extension angle of the stifle joint, longer patellar ligament, and shorter femoral trochlear length. The full extension angle of the stifle joint had the biggest area under the ROC curve. CONCLUSION: Mediolateral radiographs of the stifle joint in full extension are clinically important in dogs with MPL because some dogs might have a proximally positioned patella that is recognizable only when the stifles are extended.

Integrating MR imaging with full-surface indentation mapping of femoral cartilage in an ex vivo porcine stifle.

The potential of MRI to predict cartilage mechanical properties across an entire cartilage surface in an ex vivo model would enable novel perspectives in modeling cartilage tolerance and predicting disease progression. The purpose of this study was to integrate MR imaging with full-surface indentation mapping to determine the relationship between femoral cartilage thickness and T2 relaxation change following loading, and cartilage mechanical properties in an ex vivo porcine stifle model. Matched-pairs of stifle joints from the same pig were randomized into either 1) an imaging protocol where stifles were imaged at baseline and after 35 min of static axial loading; and 2) full surface mapping of the instantaneous modulus (IM) and an electromechanical property named quantitative parameter (QP). The femur and femoral cartilage were segmented from baseline and post-intervention scans, then meshes were generated. Coordinate locations of the indentation mapping points were rigidly registered to the femur. Multiple linear regressions were performed at each voxel testing the relationship between cartilage outcomes (thickness change, T2 change) and mechanical properties (IM, QP) after accounting for covariates. Statistical Parametric Mapping was used to determine significance of clusters. No significant clusters were identified; however, this integrative method shows promise for future work in ex vivo modeling by identifying spatial relationships among variables.

The value of routine radiographic follow up in the postoperative management of canine medial patellar luxation.

OBJECTIVE: To determine the influence of radiographic examination on the recommendations made at the time of planned re-evaluation of dogs after medial patellar luxation (MPL) surgery. STUDY DESIGN: Retrospective multi-institutional case series. ANIMALS: Client-owned dogs (N = 825) that underwent MPL surgery. METHODS: Records of 10 referral institutions were searched for dogs that had been treated surgically for unilateral MPL and underwent a planned follow-up visit, including radiographs. The frequency of, and reasons for, changes in further recovery recommendations were investigated. RESULTS: Follow up was performed at a median of 6 (range, 4-20) weeks postoperatively. Isolated radiographic abnormalities were identified in 3.3% (27/825) of dogs following MPL surgery and led to a change in recommendations in 3% (13/432) of dogs that were presented without owner or clinician concerns. Lameness, administration of analgesia at follow up, and history of unplanned visits prior to routine re-examination were associated with a change in postoperative plan (P < .001). In the absence of owner and clinician concerns, the odds of having a change in convalescence plans were not different, whether or not isolated radiographic abnormalities were present (P = .641). CONCLUSION: Routine radiographs at follow up did not influence postoperative management of most dogs after MPL surgery in the absence of abnormalities on clinical history or orthopedic examination. CLINICAL SIGNIFICANCE: Dogs that were presented for routine follow up after unilateral MPL surgery without owner concerns, lameness, analgesic treatment or a history of unplanned visits, and for which examination by a surgical specialist was unremarkable, were unlikely to benefit from radiographs.

Degree of osteophyte formation seen on radiographs provides useful prognostic information for dogs with cruciate ligament disease.

BACKGROUND: Concurrent osteoarthritis is generally present in the stifle joints of dogs with cranial cruciate ligament disease (CCLD), but it is not known if the degree of osteoarthritis-related changes affects the prognosis. Development of osteophytes is a key radiographic feature of osteoarthritis. The aim of this study was to evaluate the association between the degree of osteophyte formation seen on radiographs and CCLD-related euthanasia in dogs with CCLD. METHODS: A retrospective cohort study including 226 dogs treated for CCLD at two university animal hospitals was performed. Clinical and follow-up information was retrieved, and stifle radiographs taken during the 31 days before treatment for the CCLD were graded for osteophyte formation by three veterinary radiologists. A multivariable Cox proportional hazards model was applied to assess the association between the degree of osteophyte formation and CCLD-related euthanasia. RESULTS: An association between the degree of osteophyte formation and CCLD-related euthanasia was found, with increased osteophyte formation associated with an increased hazard of CCLD-related euthanasia (hazard ratio 1.06, 95% confidence interval 1.01-1.11, p = 0.01). LIMITATIONS: No clinical assessment of the outcome was performed. CONCLUSION: The findings suggest that evaluation of stifle radiographs for osteophyte formation could provide useful prognostic information for dogs with CCLD.

Stifle joint osteoarthritis in small-breed and medium-breed dogs is more severe after cranial cruciate ligament injury than medial patellar luxation.

This retrospective observational study aimed to characterize the severity and distribution of OA in the stifle joints of small and medium dogs with CCL injury and/or MPL. Radiographs of the stifle joints from 218 dogs from 10 small and medium breeds were included; 127 joints had CCL injury, 76 joints had MPL, and 73 joints had CCL injury and MPL. OA was graded at 33 sites within the joint. The mean ± SD OA score was 20.3 ± 9.9. For all joints, OA was more severe in heavier than lighter dogs (P = 0.003). Joints with MPL (14.9 ± 8.2) had lower OA scores than joints with CCL injury (22.2 ± 10.0, P = 0.003) or CCL injury and MPL (22.6 ± 9.4, P < 0.001). OA scores were higher in joints with MPL for older dogs (r = 0.408, P < 0.001) but did not change with age in joints with CCL injury. The pattern of OA did not differ among joints with CCL injury or MPL. The retrospective nature of the study limited findings to associations but did not allow conclusions regarding factors causing OA or enhancing its progression. We concluded that, in small- and medium-breed dogs, the patterns of stifle OA joint after CCL injury and MPL are similar. Radiographic OA after CCL injury is more severe than MPL. An increase in age leads to an increase in OA at the time of presentation at a referral hospital in stifle joints with MPL and without CCL injury.

Deep learning-based diagnosis of stifle joint diseases in dogs.

In this retrospective, analytical study, we developed a deep learning-based diagnostic model that can be applied to canine stifle joint diseases and compared its accuracy with that achieved by veterinarians to verify its potential as a reliable diagnostic method. A total of 2382 radiographs of the canine stifle joint from cooperative animal hospitals were included in a dataset. Stifle joint regions were extracted from the original images using the faster region-based convolutional neural network (R-CNN) model, and the object detection accuracy was evaluated. Four radiographic findings: patellar deviation, drawer sign, osteophyte formation, and joint effusion, were observed in the stifle joint and used to train a residual network (ResNet) classification model. Implant and growth plate groups were analyzed to compare the classification accuracy against the total dataset. All deep learning-based classification models achieved target accuracies exceeding 80%, which is comparable to or slightly less than those achieved by veterinarians. However, in the case of drawer signs, further research is necessary to improve the low sensitivity of the model. When the implant group was excluded, the classification accuracy significantly improved, indicating that the implant acted as a distraction. These results indicate that deep learning-based diagnoses can be expected to become useful diagnostic models in veterinary medicine.

[Comparison of long-term results of Tibial Plateau Leveling Osteotomy and Modified Maquet Procedure in canine anterior cruciate ligament disease]. / Vergleichende Langzeitergebnisse zwischen Tibial Plateau Leveling Osteotomy und Modified Maquet Procedure nach Ruptur des vorderen Kreuzbandes beim Hund.

OBJECTIVE: This study aims to compare the Modified Maquet Procedure (MMP) with the Tibial Plateau Leveling Osteotomy (TPLO) using long-term follow-up examinations over the period of more than one year (∅ 3,15 years) by clinical examination, radiographic assessment of osteoarthritis progression, and gait analysis by treadmill examination. Additional aim is to review the influence of surgeons' experience in TPLO technique. MATERIAL AND METHODS: This clinical study included 67 stifle joints of 50 dogs of different breeds between 20 and 40 kilograms body weight that were treated by TPLO (n = 48) or MMP (n = 19) following the rupture of the cranial cruciate ligament. The TPLO group was further divided into a group operated by two experienced surgeons (TPLO1, n = 25) and a second group operated by several surgeons with different experience (TPLO2, n = 23). Following a post-operative time period of more than one year in the least (mean, 3.15 ± 1.21 years) orthopedic and radiographic examinations as well as separate unilateral and bilateral gait analyses were conducted. In addition, gait analysis data were compared with an orthopedically healthy control group. RESULTS: No significant and clinically relevant differences were observed between the 3 groups in the results of their orthopedic examination.Osteoarthritis progression showed similar values in all 3 surgical groups. On average per year this feature was slightly but statistically significantly lower in the TPLO2 group in comparison to the TPLO1 and MMP groups.Gait analysis during walking exhibited significant differences in bilateral ruptures at the Peak Vertical Force and the Vertical Impulse, especially when compared to the healthy control group. Stance phase duration did not show any significant differences. At trot, no significant differences were found between the 3 surgical groups. CONCLUSION: Both surgical techniques achieved good clinical, radiological, and gait analysis results in the 3 groups at long-term follow-up, even when compared with a healthy control group. CLINICAL RELEVANCE: MMP can be considered a rapid feasible alternative to the established TPLO method also bearing satisfactory results in dogs. The degree of the surgeon's experience does not seem to influence the outcome.

MRI Tracking of Iron Oxide Labelled Canine Mesenchymal Stem Cells in Artificial Stifle Defects.

OBJECTIVES: The aim of this study was to describe ultrasmall superparamagnetic iron oxides labelling of canine adipose-derived mesenchymal stem cells (AdMSCs) and the detection and semiquantitative evaluation of the labelled cells after implantation in artificial canine stifle defects using magnetic resonance imaging. METHODS: Magnetic resonance imaging examinations of 10 paired (n = 20) cadaveric stifle joints were evaluated after creation of chondral defects and embedding of ultrasmall superparamagnetic iron oxides labelled canine mesenchymal stem cells. To prove the feasibility of the labelling for in vivo usage, Prussian blue staining, cell vitality tests and intralesional administration of labelled cells were conducted. Magnetic resonance imaging of ex vivo defects filled with different cell concentrations was obtained to depict the cell content semiquantitatively via signal intensity measurements (region of interest). RESULTS: Prussian blue staining showed that the labelling was effective. According to the vitality tests, it had no significant short-term influence on cell viability and proliferation rate. For the evaluation of the defect T2* sequences were feasible and stifle defects were visible allowing measurements of the signal intensity in all cases. Increasing the cell concentration within the chondral defects resulted in an inversely proportional, significant reduction of signal intensity according to the region of interest. CLINICAL SIGNIFICANCE: Ultrasmall superparamagnetic iron oxides labelling was effective. The detection of the AdMSCs in a complex anatomical structure like the surface of the femoral condyle was possible and the T2* signal intensity of the implant region was significantly correlated with the concentration of the AdMSCs.

Morphometric assessment of the medial collateral ligament of the canine stifle joint.

OBJECTIVE: The study provides a morphometric assessment of the medial collateral ligament (MCL) of the canine stifle joint. STUDY DESIGN: Eighty-six stifle joints were collected from 43 canine cadavers and dissected to free them of soft tissue and expose the collateral ligaments. The MCL insertion sites were identified with Chinese ink on intact stifle joints and also marked with radiopaque paste after removal of the MCL. Mediolateral photographs and radiographs of each stifle joint were taken after MCL was removed for morphometric assessment. Measurements were taken in two groups: a group of Beagles (group 1), and a group composed of different breeds (group 2). RESULTS: In all stifle joints, the MCL had an hourglass shape. It inserted in the distal femur and the proximal tibia, and was also intimately attached to the medial meniscus and more loosely to the proximal tibial epiphysis in its central portion. The MCL tibial insertion (TI) site had the largest surface area. Its proximal and distal position relative to the tibial plateau was located at 8.24 ± 1.17% and 15.54 ± 1.50% respectively of the total tibial length in group 1, and at 8.86 ± 1.93% and 15.53 ± 2.11% respectively, of the total tibial length in group 2. These values were not statistically different. CONCLUSION: The MCL of the canine stifle joint has an insertion site on the femur and on the tibia and is also attached on the medial meniscus. The location of the MCL TI site seems to be relatively homogeneous in dogs.

Use of Blumensaat's line for assessment of cranial tibial subluxation in dogs with cranial cruciate ligament deficiency.

BACKGROUND: This study aimed to determine whether Blumensaat's line, a consistently present radiographic feature delineating the peak of the femoral intercondylar fossa, could be used to assess for cranial tibial subluxation in canine stifles with cranial cruciate ligament disease. METHODS: Thirty sequential, neutrally positioned, standing-angle stifle radiographs were taken from dogs presenting to a specialist referral centre for treatment of cruciate ligament disease. Thirty similarly positioned radiographs of healthy canine stifles were used as a control group. The radiographs were anonymised and submitted to blinded observers for measurement of the tibial plateau angle, patella tendon angle, Blumensaat's line length and the length of Blumensaat's line cranial to the tibial mechanical axis. RESULTS: Finding that the tibial mechanical axis intersects Blumensaat's line cranial to its midpoint, as a marker of cranial tibial subluxation, had a positive predictive value of 76% for subsequent surgical identification of cruciate ligament disease. CONCLUSIONS: Tibial cranial subluxation is detectable and quantifiable radiographically using the intersection of the tibial mechanical axis and Blumensaat's line. Once quantified, this measurement could be used both as a radiographic marker of cruciate ligament disease and to adjust tibial osteotomy procedures to minimise the risk of under advancement of the tibial tuberosity resulting in a persistently unstable stifle.

Ex vivo comparison of 3 Tesla magnetic resonance imaging and multidetector computed tomography arthrography to identify artificial soft tissue lesions in equine stifles.

OBJECTIVE: To determine the diagnostic performance of computed tomographic arthrography (CTA) and 3 Tesla magnetic resonance imaging (MRI) for detecting artificial meniscal, meniscotibial ligament (MTL) lesions and cruciate ligament (CL) lesions in horses. STUDY DESIGN: Ex vivo controlled laboratory study. ANIMALS: Nineteen stifles from adult horses. METHODS: Stablike defects (n = 84) (16 mm long, 10 mm deep) were created in the menisci (n = 35), CLs (n = 24), and MTLs (n = 25) via arthroscopy prior to MRI and CTA (80 mL contrast at 85 mg/mL per joint). Two radiologists, unaware of the lesions, reached a consensus regarding the presence of lesions, based on 2 reviews of each study. Sensitivity and specificity of MRI and CTA were determined using arthroscopy as a reference and compared with McNemar's tests. RESULTS: The sensitivity and specificity of MRI (41% and 86% respectively) and CTA (32% and 90% respectively) did not differ (P = .65). The sensitivity (MRI: 24%-50%; CTA:19%-40%) and specificity (MRI: 75%-92%; CTA 75%-100%) of imaging modalities did not differ when detecting lesions of the menisci, MTLs, and CLs (P = .1-1.0). The highest sensitivities were achieved when MTLs were evaluated with MRI (50%) and CLs with both modalities (40%). CONCLUSIONS: The diagnostic performance of CTA was comparable with that of MRI, with a low to moderate sensitivity and high specificity. CLINICAL SIGNIFICANCE: Computed tomographic arthrography should be considered as an adjunct to diagnose CL injuries. This is important for equine clinicians, as the CL cannot be visualized adequately using basic imaging techniques preoperatively.