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.

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.

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.

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.

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.

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.

[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.

Comparison of four methods to -determine cage width in tibial tuberosity advancement.

INTRODUCTION: The objective of this study was to test a method for determining the width of the tibial tuberosity advancement (TTA) cage without the need for extension of the stifle joint, while producing preoperative radiographs. TTA cage size was determined by applying 4 different methods using radiograph images in mediolateral direction of fully extended stifles of dogs (n=43), with and without naturally occurring cranial cruciate ligament disease: parallel shift (PS) method, common tangent (CT) method, «2,1¼ method (cage size = 2,1 × tibia plateau length - tibial tuberosity width), and margo cranialis (MC) method (cage size = length of MC/6*1,75). Two new methods, «2,1¼, and MC were compared to the existing CT and PS methods. All 4 methods resulted in reliable cage sizes. Intraclass correlation coefficients showed an excellent reliability of the CT and PS to the «2,1¼ method and a good reliability in regards to the MC method. In conclusion, TTA cage size of the tibia anatomy alone can be determined on radiographs without the need of full extension of the stifle joint. Based on the results, two different methods of cage size measurement are recommended in order to increase diagnostic accuracy and to prevent the insertion of suboptimal cages.

INTRODUCTION: L'objectif de cette étude était de tester une méthode pour déterminer la largeur de la cage d'avancement de la tubérosité tibiale (TTA) sans avoir besoin d'extension du grasset, tout en réalisant des radiographies préopératoires. La taille de la cage TTA a été déterminée en appliquant 4 méthodes différentes, utilisant des images radiographiques dans l'axe médiolatéral des grassets complètement étendus de chiens (n ​​= 43), avec et sans pathologie naturelle du ligament croisé antérieur: méthode du décalage parallèle (PS), méthode de la tangente commune (CT), méthode «2,1¼ (taille de la cage = 2,1 × longueur du plateau du tibia ­ largeur de la tubérosité tibiale) et méthode de la margo cranialis (MC) (taille de la cage = longueur de MC/6*1,75). Deux nouvelles méthodes, «2,1¼ et MC ont été comparées aux méthodes CT et PS existantes. Les 4 méthodes ont abouti à des tailles de cage fiables. Les coefficients de corrélation intra classe ont montré une excellente fiabilité du CT et du PS avec la méthode «2,1¼ et une bonne fiabilité vis-à-vis de la méthode MC. En conclusion, la taille de la cage TTA de l'anatomie du tibia seule peut être déterminée sur des radiographies sans qu'il soit nécessaire d'étendre complètement l'articulation du grasset. Sur la base des résultats, deux méthodes différentes de mesure de la taille des cages sont recommandées afin d'augmenter la précision du diagnostic et d'empêcher la mise en place de cages sous-optimales.

Near infrared spectroscopic evaluation of biochemical and crimp properties of knee joint ligaments and patellar tendon.

Knee ligaments and tendons play an important role in stabilizing and controlling the motions of the knee. Injuries to the ligaments can lead to abnormal mechanical loading of the other supporting tissues (e.g., cartilage and meniscus) and even osteoarthritis. While the condition of knee ligaments can be examined during arthroscopic repair procedures, the arthroscopic evaluation suffers from subjectivity and poor repeatability. Near infrared spectroscopy (NIRS) is capable of non-destructively quantifying the composition and structure of collagen-rich connective tissues, such as articular cartilage and meniscus. Despite the similarities, NIRS-based evaluation of ligament composition has not been previously attempted. In this study, ligaments and patellar tendon of ten bovine stifle joints were measured with NIRS, followed by chemical and histological reference analysis. The relationship between the reference properties of the tissue and NIR spectra was investigated using partial least squares regression. NIRS was found to be sensitive towards the water (R2CV = .65) and collagen (R2CV = .57) contents, while elastin, proteoglycans, and the internal crimp structure remained undetectable. As collagen largely determines the mechanical response of ligaments, we conclude that NIRS demonstrates potential for quantitative evaluation of knee ligaments.

Determining the Variation in the Tibial Tuberosity Transposition Distance That Is Required to Correct the Quadriceps Angle With the Severity of Medial Patellar Luxation of the Canine Stifle Joint.

The aim of this study was to evaluate the transposition distance in in vitro canine medial patellar luxation (MPL) models of different severity grades using a single radiograph of the stifle joint. Each MPL grade model was generated with manipulation and evaluated by palpating the stability of the patella. An anterior-posterior radiograph of the entire hind limb with extended hip and stifle joints, including the iliopubic eminence, was used for all measurements. The quadriceps angles and the percentage of the transposition distance to the maximum width of the proximal tibia were measured. Our results demonstrated that when the tibial tuberosity transposition procedure is performed in a clinical setting, the required distance to correct the abnormal direction of the extensor mechanism in the canine stifle joint was greater in severe grade MPL than in mild grade MPL.

Evaluation of Hindlimb Deformity and Posture in Dogs with Grade 2 Medial Patellar Luxation during Awake Computed Tomography Imaging while Standing.

OBJECTIVE: The aim of this study was to determine the degree of bone deformities and hindlimb postural abnormalities in a standing position in awake Toy poodles with and without grade 2 medial patellar luxation (MPL) using high speed 320-row computed tomography (CT). METHODS: The limbs with grade 2 MPL (MPL-G2 group) and without any orthopaedic disorders (control group) were imaged in a standing position, without sedation or anaesthesia, using CT. In MPL-G2 group, images were obtained when the patella was luxated (G2-L group) and reduced (non-luxation, G2-NL group). Bone morphologies of the femur and tibia were quantified three-dimensionally. Hindlimb standing posture was evaluated by measuring femoral rotation and abduction angles, tibial rotation angle, metatarsal rotation angle, foot rotation angle, angle between the femoral anatomical axis and the mechanical axis of hindlimb and stifle joint line convergence angle. RESULTS: There were no significant differences in bone morphologic parameters between the MPL-G2 group (5 limbs) and the control group (6 limbs). In the G2-NL group, there were no significant hindlimb postural abnormalities. In contrast, in the G2-L group, significant hindlimb postural abnormalities including external rotation of femur, internal rotation of tibia and foot, external rotation of tarsal joint, large stifle joint convergence angle, genu varum and toe-in standing were observed. CONCLUSION: Dogs with grade 2 MPL have no bone deformities but show abnormal standing posture when the patella is luxated.