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1.
Measurement of the tibial plateau slope from lateral hind-limb radiographs is a preoperative requirement when performing tibial plateau leveling osteotomy (TPLO) for repair of the cruciate-deficient stifle in dogs. Two measurements of the tibial plateau slope in 312 stifles of 156 dogs were taken from lateral radiographs by each of three observers with varying degrees of experience in the measurement method. Intraobserver variability was +/-3.4 degrees, and interobserver variability was +/-4.8 degrees. No significant differences were identified for the intraobserver measurements; however, in evaluating interobserver variability, a significant difference was found between the inexperienced observer and the two experienced observers.  相似文献   

2.
The aim of the present study was to establish which adrenal gland measurement was characterized by the least variations. To do this, we quantified the variability of seven different size measurements of the canine adrenal gland (maximal length, maximal height at the cranial and caudal poles on longitudinal and transverse images, and maximal width of the cranial and caudal poles) within observer, between observer, and between dogs based on three different measurements made by each of the three observers in six healthy Beagle dogs. The height of the caudal pole of both adrenal glands measured on longitudinal images had the lowest intra‐ and interobserver variability, while measurements of the length had the highest intra‐ and interobserver variability. Other measurements that were characterized by low intra‐ and interobserver variability were: height and width of the caudal pole on transverse images and height of the cranial pole on longitudinal images only. These results provide a basis for further study of the changes in adrenal gland size in dogs with pituitary‐dependent hyperadrenocorticism.  相似文献   

3.
OBJECTIVE: To determine (1) the inter- and intraobserver variability in measurement of tibial plateau angle (TPA), (2) whether this inter- and intraobserver variability is related to the characteristics of the dog (age, size, and amount of degenerative joint disease [DJD]) and the experience level of the observer, and (3) the extent of any relationship between interobserver variability of TPA and the variability of the observers' selection of the specific cranial and caudal points along the tibial plateau. STUDY DESIGN: Examination of tibial radiographs of 40 dogs clinically affected with a cranial cruciate ligament (CrCL)-deficient stifle joint. METHODS: Eleven different observers, divided into 3 groups based on their level of experience with the tibial plateau leveling osteotomy (TPLO) technique, measured the TPA on all 40 radiographs on 5 different occasions. The degree of DJD present in the stifle joint was independently graded as an overall measure and then again as it specifically related to the cranial and caudal points along the tibial plateau. The total observed variabilities of the TPA were assessed with reference to interobserver differences, intraobserver differences, and among the groups of observers with respect to the different dog characteristics. Finally, the specific points selected on the radiographs were reexamined to determine whether any variability was present in cranial and caudal point selection. RESULTS: The interobserver standard deviation of the TPA measurements for each dog was 0.8 degrees, and the intraobserver standard deviation was 1.5 degrees. The TPA measurements obtained by the 11 observers differed significantly from each other (P <.001); however, there was no significant difference of TPA among the different groups of observers (P =.67). There was no significant correlation observed between either the inter- or intraobserver variability and the dog characteristics. Specific point data and their relationship to the various variables of dog characteristics and inter- and intraobserver TPA variability revealed significant correlations only to the amount of DJD present at the caudal point (P =.001). CONCLUSIONS: Interobserver variation, but no significant group variation, was present. Overall DJD did not appear to be related to the variability in TPA angle measurement. Most of the interobserver variability was attributable to variability in horizontal point selection at both the cranial and caudal points and vertical point selection at the caudal point. It appears that degenerative changes that specifically obscure the points on the tibial plateau, especially at the caudal point, are responsible for most of the interobserver variation. CLINICAL RELEVANCE: The desired postoperative TPA of 5 degrees is dependent on a precise initial measure of TPA preoperatively. This study indicates that there is statistically significant interobserver variability with measurement of TPA, which, therefore, can result in a similar amount of variability with the final tibial plateau slope obtained postoperatively.  相似文献   

4.
Reasons for performing study: Criteria for the radiographic evaluation of navicular bones in horses have been published to standardise classification of radiographic signs. However, intra‐ and interobserver agreement have not been established. Objective: To determine intra‐ and interobserver agreement in the evaluation of radiographic and computed tomographic (CT) navicular changes. It was hypothesised that: 1) intraobserver agreement would be better than interobserver agreement; 2) agreement would be better for CT than for radiography; and 3) pathological changes would be recognised with greater certainty with CT. Methods: Radiographs and CT scans of 60 cadaver navicular bones were evaluated by 3 observers using published criteria. A subset of 30 studies was evaluated twice by one observer. Agreement was tested using the kappa statistic. Certainty about pathological changes was evaluated by giving the observers the option to choose ‘not sure’. Results: Agreement varied from poor to almost perfect for radiographic evaluation and from poor to substantial for CT evaluation. For radiographic evaluation mean interobserver agreement was fair, as it was for CT evaluation. For radiographic evaluation mean intraobserver agreement was moderate as it was for CT evaluation. Pathological changes were evaluated with greater certainty on CT scans compared to radiographs; however, this was not associated with improved agreement. Conclusions: Variations in classification of navicular lesions in radiographic and CT studies were considerable between and within observers and challenge the use of such studies for diagnostic and prognostic purposes. Potential relevance: The results of this study allowed the identification of evaluation criteria with sufficient precision to be useful for navicular bone evaluation.  相似文献   

5.
OBJECTIVE: To determine the reproducibility and accuracy of computed tomographic (CT) measurements of pituitary gland dimensions in healthy dogs. ANIMALS: 35 healthy sexually intact adult dogs. PROCEDURES: 2 observers independently viewed CT images of the skull in 35 dogs twice. Pituitary gland height, width, length, and volume and pituitary gland height-to-brain area ratio (P:B ratio) were measured or calculated. Intraobserver and interobserver agreement indexes (AIs) were calculated for pituitary gland dimensions. Computed tomography was performed also on 5 phantoms, and both observers measured phantom dimensions twice. True-value AIs were calculated for the phantom study. RESULTS: The mean +/- SD interobserver AI between observer 1 and 2 for pituitary gland height and the P:B ratio was 0.90 +/- 0.07. The intraobserver AI for pituitary gland height and the P:B ratio was 0.97 +/- 0.04 for observer 1 and 0.94 +/- 0.04 for observer 2. The intra and interobserver AIs for the other dimensions were lower than those for pituitary gland height and the P:B ratio. All phantom dimensions on CT images were underestimated significantly, compared with their true values. CONCLUSIONS AND CLINICAL RELEVANCE: The intra- and interobserver AIs for pituitary gland dimension measurements on CT images were high. However, the same observer preferably should perform serial measurements. Window settings influence pituitary gland dimension measurements, and predetermined window settings are recommended to make comparisons among dogs. Pituitary gland dimension measurements made from CT images in our study underestimated the true values.  相似文献   

6.
Reason for performing study: Different examiners or the same examiner were observed at different times producing slightly different results when obtaining cervical‐vertebral ratios. If the difference is substantial, then measurement variability would have an important impact of radiographic interpretation. Objective: To quantify agreement and repeatability of these measurements. Methods: An observer agreement study was performed using 75 horses. Measurements were made at C3–4 and C6–7 by a board‐certified radiologist and an imaging resident. Intra‐ and interobserver agreement was quantified using Bland‐Altman plots. Repeatability was assessed as the percentage of differences between duplicate measurements by the radiologist that were within ± 2 s.d. of the differences. Results: At C3–4, the limits of agreement for the intra‐vertebral ratio were between ‐5 and 4% for the intra‐ and ‐5 and 6% for interobserver comparison. For the intervertebral ratio, they were between ‐9 and 8% for the intra‐ and ‐10 and 10% for interobserver comparison. At C6–7, the limits of agreement for the intra‐vertebral ratio were between ‐6 and 5% for the intra‐ and ‐6 and 8% for interobserver comparison. For the intervertebral ratio, they were between ‐7 and 7% for the intra‐ and ‐6 and 13% for interobserver comparison. At C3–4, all measurements were 95% repeatable (differences typically ≤4% and always ≤8%) for the intra‐vertebral ratio and 96% repeatable (differences typically ≤8% and always ≤11%) for the intervertebral ratio. At C6–7, all measurements were 98% repeatable (differences typically ≤6% and always ≤7%) for the intravertebral ratio and 92% repeatable (differences typically ≤6% and always ≤10%) for the intervertebral ratio. Conclusions: Cervical‐vertebral ratios typically varied by 5–10% within and between examiners. Potential relevance: When using cervical‐vertebral ratios in practice, the impact of measurement agreement should be factored into the interpretation of the test result because measurement variability may lead to misdiagnosis and limit the clinical usefulness of these tests.  相似文献   

7.
Objectives : The objectives of this study were to quantify the sensitivity and specificity of visual assessment of radiographs of the canine elbow in detecting ulnar trochlear notch sclerosis, to establish interobserver and intra‐observer variation for the presence and grade of sclerosis and to quantify the effect of radiographic exposure on observer grading. Methods : Mediolateral elbow radiographs were obtained from Labrador retrievers (n=34) aged between six and 18 months. Radiographs from dogs with an arthroscopic diagnosis of fragmented medial coronoid process (n=17) and those from a control population (n=17) were subjected to observer grading for the presence or absence of and the grade of ulnar trochlear notch sclerosis. Interobserver and intra‐observer variation and observer sensitivity and specificity were calculated. Digital data from the ulnar trochlear notch were correlated with mean observer grade to quantify the effect of radiographic exposure on observer grade. Results : Interobserver agreement was “fair” (kappa=0·251 to 0·369) and intra‐observer agreement was “moderate” to “substantial” (kappa=0·462 to 0·667). The sensitivity of observer assessment was 72 per cent with a specificity of 22 per cent. Mean observer grade was not significantly correlated with the degree of radiographic exposure (P=0·70). Clinical Significance : Ulnar trochlear notch sclerosis is a phenomenon associated with fragmented medial coronoid process. However, interobserver agreement in grading this feature is only fair, being identified by observers with moderate sensitivity but with relatively poor specificity. This low specificity may predispose to overdiagnosis in clinical cases. Intra‐observer agreement is moderate to substantial, suggesting that individuals can reliably quantify this radiological feature on multiple occasions. The ability of observers to assess the degree of sclerotic change is not significantly affected by radiographic exposure.  相似文献   

8.
Elbow incongruity is a form of elbow dysplasia that causes osteoarthritis, pain, and lameness, and it is common in chondrodystrophic dog breeds. The objective of this retrospective secondary analysis study was to evaluate the intra‐ and interobserver repeatability of a novel radiographic incongruity grading system for assessing elbow incongruity in three chondrodystrophic dog breeds—the dachshund, Skye Terrier, and Glen of Imaal Terrier. We conducted an observer agreement study that included 220 mediolateral antebrachial radiographs from 110 dogs with the elbow in 90° flexion. The radiographs were independently assessed by three observers at three time points, using a four‐stepped grading scale. The proportion of agreement and Kappa coefficient were calculated. Both the intra‐ and interobserver proportions of agreement were substantial when three grades were required to be identical (.705‐.777 and .609, respectively), and almost perfect for two identical grades (.991‐1.000 and .991, respectively). Some differences in repeatability between breeds were noted; specifically, the intraobserver repeatability was higher in the dachshund, and the interobserver repeatability was lower in the Glen of Imaal Terrier. Our study showed that the radiographic imaging protocol and incongruity grading system have high repeatability when assessing elbow incongruity in chondrodystrophic dog breeds.  相似文献   

9.
Objective: To determine (1) risk factors for fibular fracture after tibial plateau leveling osteotomy (TPLO) and (2) if a single postoperative radiographic measurement or measurement ratio of the proximal tibial fragment can be used as a predictor for fibular fracture. Study Design: Multivariate retrospective clinical study. Animals: Dogs (n=326) with cranial cruciate ligament rupture that had TPLO (n=355). Methods: Medical records (January 2004–November 2007) and radiographs of dogs that had TPLO were reviewed. TPLO plate type, distance between tibial plateau and proximal screw, proximodistal tibial plateau fragment length, tibial plateau width, the presence of a fibular drill hole filled with a screw or not, and fibular fractures were recorded. Results: The odds of having a fibular fracture were 10 times greater in dogs with a fibular drill hole than in dogs without a drill hole. The odds of having a fibular fracture were 1.46 times greater for every 4.5 kg increase in body weight. Tibial plateau angle (TPA) at the time of reevaluation was larger than the postoperative TPA and TPA increase was larger in dogs with fibular drill holes than without (P<.01) and in dogs with fibular fractures than without (P<.01). Conclusion: An unfilled fibular drill hole and increased body weight are risk factors for fibular fracture.  相似文献   

10.
The repeatability of ultrasonographic measurements of the canine thyroid gland was evaluated. The variability of three different parameters (the maximal length, width, and height) within observer, between observer and between dogs was assessed based on three different measurements made by each of three observers infive healthy beagle dogs. From the three parameters, the volume of the gland was estimated using a formula of a rotation ellipse. The height and the volume had the lowest intra- and interobserver variability, while measurements of the length had the biggest intra- and interobserver variability. The mean values, with their 90% confidence interval were: height = 0.53cm [0.33-0.73], length = 2.45cm [2.04-2.85], width = 0.62cm [0.46- 0.78], volume = 0.38 cm3 [0.20-0.55].  相似文献   

11.
Objective-To compare calibration methods for digital radiography in terms of measurement accuracy and interobserver variability. Design-Prospective study. Sample-Digital radiographic images of a 155-mm-long Steinmann pin. Procedures-Measurement of pin length on digital radiographs was determined with a 25.4-mm-diameter calibration ball and commercially available software program via 3 calibration methods (ie, no calibration, autocalibration, and manual calibration). Digital radiographs of the calibration ball and pin were obtained with each placed at various vertical heights from the table (7 heights) and horizontal distances from the center of the beam (4 distances). Measurements of pin length on digital radiographs were made by 4 observers who were blinded to the orientation of the calibration ball and pin. Results-Pin lengths obtained by each calibration method were significantly different from each other and from the true value. Manual calibration was the most accurate. There was no significant interobserver variability in measurements. There was no significant change in measurements when the calibration ball was moved horizontally, but pin length measurements changed significantly when the ball was moved vertically (away from the table) with an approximate magnification error of 1% per centimeter of distance between the calibration ball and pin. Conclusions and Clinical Relevance-For digital radiography, manual calibration is recommended to achieve the most accurate measurements. Ideally, the calibration ball should be placed at the same vertical height as the object to be measured; however, if this cannot be achieved, the magnification error can be expected to be approximately 1% per centimeter of distance.  相似文献   

12.

Background

Sagittal ratio values (SRVs) of cervical vertebrae are used for ante‐mortem diagnosis of cervical vertebral stenotic myelopathy, but intraobserver and interobserver variability in measurement may influence radiographic interpretation of vertebral stenosis in horses with neurological disease.

Objectives

To determine intraobserver repeatability in SRVs, intra‐ and interobserver agreement in SRVs and whether or not agreement was influenced by animal age.

Animals

Forty‐two horses (>1 year old) with neurological disease from which laterolateral computed radiographic images of C2–C7 were obtained.

Methods

Four observers made measurements from C2 to C7 for each horse and interobserver agreement for intra‐ and intervertebral SRVs was determined using Bland–Altman analysis (acceptable agreement: limits of agreement [LOA] ≤ 0.05) on all horses and those ≤3 (n = 25) and >3 (n = 17) years old. Each observer also made repeated measurements for 10 horses and intraobserver repeatability and agreement were determined.

Results

Adequate intraobserver repeatability was achieved for 6 sites. Within observers, paired measurements had a median difference ≤5.7%, but a large range in differences often occurred, most frequently at intervertebral sites. For C5, C6, C7, and C3–4, LOA ≤ 0.05 were achieved by at least 1 observer. With the exception of C5 for 1 pair, LOA were >0.05 for interobserver agreement, regardless of animal age. LOA were largest at intervertebral sites.

Conclusions and Clinical Importance

Within and between observers, measurement error may limit the diagnostic accuracy of SRVs and result in discrepancies of diagnosis and treatment and warrants consideration when used clinically in horses with neurological disease.  相似文献   

13.
Objective— To compare rates of contralateral cranial cruciate ligament rupture (CCLR) in Labradors based on age and weight at initial rupture, sex, and tibial plateau angle (TPA) and to determine whether Labradors that rupture their initial cranial cruciate ligament (CCL) at an earlier age (<4 years) are more likely to rupture their contralateral side within a certain period of time. Study Design— Case series. Animals— Labradors (n=94) that had tibial plateau leveling osteotomy (TPLO). Methods— Two groups: no contralateral rupture (NR) and contralateral rupture (CR) were compared for significant (P<.05) differences in percentage of subsequent cruciate tears using a Wilcoxon's rank‐sum tests for continuous variables and Fisher's exact test for sex. Adjusted odds ratios for likelihood of subsequent cruciate tears (yes/no) were estimated using logistic regression. Associations of these characteristics with time to subsequent rupture were assessed using Kaplan–Meier survival analysis estimation. Predictors of presentation with bilateral ruptures (BR) versus single rupture were also evaluated using Wilcoxon's rank‐sum tests and a generalized Fisher's exact test. Results— Subsequent CCLR occurred in 45 dogs (48%), and BR on admission were identified in 10 dogs (10.6%). Comparing NR and CR dogs, there were no significant differences between age or weight at initial rupture, sex or TPA; however there were associations toward longer time to CR for dogs older than the median age and female dogs (intact and spayed). There were no significant differences in age, sex, weight, or TPA of dogs with bilateral CCL ruptures compared with initial unilateral ruptures; however, there was a trend toward dogs presenting at an older age and with lower TPA's in the BR group. Among the 84 NR/CR dogs, the median time to rupture of the contralateral CCL was 5.5 months (95% CI 5.2–5.7). Conclusions— Age and weight at initial rupture, sex, and TPA does not affect likelihood or rate of contralateral CCL rupture or presentation with bilateral CCL ruptures. Clinical Relevance— Approximately 50% of Labradors will rupture the contralateral CCL within 5.5 months of the initial rupture but age, weight, sex, and TPA cannot be used as predictive features.  相似文献   

14.
OBJECTIVE: To determine the change in tibial plateau angle (TPA) during healing after tibial plateau leveling osteotomy (TPLO) performed for cranial cruciate ligament insufficiency in dogs and to examine factors that may be associated with the change. STUDY DESIGN: Retrospective study. STUDY POPULATION: One hundred and forty-nine canine stifles after TPLO procedure. METHODS: Records of dogs that had TPLO were reviewed. Patient age, weight, sex, breed, pre- and postoperative TPA, recheck TPA, time to recheck, type of implant used, and radiographic evidence of healing were analyzed. RESULTS: Mean time to recheck evaluation was 46 days (range, 28-65 days). Mean difference between immediate postoperative and recheck TPA measurements was 1.5 degrees (range, -3 to 9 degrees). Recheck TPA was a significantly greater (numerically higher) than immediate postoperative TPA (P<.0001). There was no significant effect of patient weight, type of plate used, or healing status of the osteotomy at the time of recheck. No correlation between pre- or postoperative TPA angles and change in TPA angle was detected. CONCLUSIONS: TPA changes during osteotomy healing after TPLO, but factors influencing this change were not identified. CLINICAL RELEVANCE: TPA may increase during healing after TPLO despite apparently adequate osteotomy fixation. The clinical relevance of this increase is unknown but is likely minimal.  相似文献   

15.
Measurement of glomerular filtration rate (GFR) via gamma camera uptake of 99mTc‐diethylenetriaminepentaacetic acid is a standard method for quantifying renal function. Aims of this retrospective, observer agreement study were to determine intra‐ and interobserver variation in GFR values for cats with chronic kidney disease and to determine whether renal insufficiency classification changed between observers. Guideline cut‐points were established for the difference in repeated GFRs to differentiate changes caused by therapeutic effect vs. inherent variation. Included cats had a diagnosis of chronic kidney disease and had undergone GFR examinations between the years of 2010 and 2013. Twenty‐nine GFR studies were sampled. Each study was read twice, 6 months apart, by two veterinary radiologists and one radiology resident. Modified Bland–Altman plots were used to investigate differences between readings 1 and 2 by observer and between pairs of observers by reading. Reliability of clinical classification was assessed through comparisons between readings and observers. Measurements were not systematically different between readings for the experienced observers but were higher in reading 1 than reading 2 for the inexperienced observer. Measurements were not systematically different between the experienced observers in reading 1 or between any two observers in reading 2. Reliability for GFR measurements was high among experienced observers; variations in GFR measurements rarely led to differences in clinical classification. Results suggested that, for experienced observers, changes in GFR values following treatment in cats with chronic kidney disease between ?0.4 and 0.4 mL/min/kg may be due to inherent variability rather than treatment effect.  相似文献   

16.
OBJECTIVES: To determine the agreement between observers and to investigate the effect of observer experience in diagnosing canine hip dysplasia and providing final scoring of hips using the standard ventrodorsal hip-extended radiographic method. The agreement of the final scoring, with a presumed correct assessment based on the Norberg angle, is also investigated. METHODS: Thirty observers were requested to read 50 ventrodorsal hip-extended radiographs of 25 dogs according to Federation Cynologique International criteria. Groups of experienced (nine members) and inexperienced (21 members) observers were used. RESULTS: For providing the distinction between dysplastic versus non-dysplastic dogs, the average interobserver agreement was 72 per cent and was significantly higher (P<0.0001) than the score that could be expected by chance without any agreement between observers. For providing the final score (A, B, C, D or E), an average interobserver agreement of 43.6 per cent was found. In the experienced group, an agreement score of 76 per cent was found for the distinction between AB versus non-AB and an agreement score of 81 per cent was found for the distinction between C versus non-C. The agreement score was significantly higher (P<0.0001) for the experienced group than for the inexperienced group in all cases. Agreement between the presumed correct assessment based on the Norberg angle and the observer's evaluation was low (P=0.35), irrespective of whether the observers were experienced (71.8 per cent correct assessments) or inexperienced (69 per cent correct assessments). CLINICAL SIGNIFICANCE: Although interobserver agreement is low, observer experience increases agreement.  相似文献   

17.
Pre-operative digital radiographs from 50 dogs undergoing a tibial plateau leveling osteotomy were evaluated. Tibial plateau angles were measured directly on printed films and measured on digital images using two different commercial DICOM viewers. The radiographs were scored for osteoarthritis and positioning. Using pooled results, the mean TPA from the digital images employing Web1000 (26.47 degrees +/- 3.90) was significantly higher then the mean TPA using film radiographs (25.41 degrees +/- 3.51), or IQ-View Pro (25.48 degrees +/- 3.89). There was not a significant difference between mean TPA using radiographs or IQ-view. Digital TPA measurement using built-in angle calipers in the clinical setting is a valid technique compared to measurements from film radiographs, and produces reproducible results. However, before changing to digital measurements, the chosen software programme should be validated against measurements using film radiographs to determine the magnitude of differences.  相似文献   

18.
OBJECTIVE: To describe a surgical technique, and outcome, for treatment of cranial cruciate ligament (CrCL) deficient stifle joints with excessive tibial plateau angle (TPA) by combined tibial plateau leveling osteotomy and cranial closing wedge osteotomy (TPLO/CCWO). STUDY DESIGN: Retrospective clinical study. ANIMALS: Fifteen client-owned dogs (18 stifle joints). METHODS: Medical records of dogs that had TPLO/CCWO were reviewed. Pre- and postoperative TPA, CCWO technique, method of fixation and complications were recorded. In-hospital re-evaluation of limb function and length of time to radiographic healing was reviewed. Long-term outcome was assessed by owner telephone interview. RESULTS: Mean pre- and postoperative TPA was 42 degrees and 8 degrees, respectively. The Slocum biradial saw was used to create the CCWO in 4 stifle joints (mean postoperative TPA, 16 degrees) and a sagittal saw was used in 14 stifle joints (mean postoperative TPA, 5 degrees). Postoperative surgical complications were documented in 77.8% of cases; including patellar tendon thickening (61.1%), and implant loosening or breakage (27.8%), seroma formation (11.1%), and local irritation (11.1%). A second surgical procedure was performed in one-third of cases primarily to retrieve implants. Mean time to documented radiographic healing was 18 weeks. Final in-hospital re-evaluation of limb function (mean, 23 weeks postoperatively) was recorded as no lameness in 73.3% and mild lameness in 26.7%. All interviewed owners were satisfied with outcome and 90.9% reported marked improvement or a return to preinjury status. CONCLUSIONS: Long-term clinical outcome of TPLO/CCWO was very good in dogs with excessive TPA, with high owner satisfaction. Longer healing times and a higher complication rate were observed compared with TPLO alone. CLINICAL RELEVANCE: TPLO/CCWO of the tibia in stifle joints with excessive TPA allows for full correction of the TPA to 5 degrees without eliminating buttress support of the tibial tuberosity.  相似文献   

19.
OBJECTIVE: To evaluate the effect of tibial plateau leveling on the biomechanics of the canine stifle. STUDY DESIGN: Analysis of a 3-dimensional (3-D) anatomically accurate theoretical model of the canine stifle. METHODS: A 3-D, 3-segment mathematical model of the normal canine stifle was modified to simulate the effect of rotation of the tibial plateau during tibial plateau leveling osteotomy (TPLO). The model examined the normal stifle, the stifle with a tibial plateau angle (TPA) of 0 degrees, and the stifle with a TPA of 5 degrees. Analysis of the models at 10 consecutive equally spaced positions during the stance phase yielded data such as ligament forces and joint reaction forces at each position. RESULTS: Rotation of the tibial plateau to a TPA of 0 degrees almost eliminates forces in the cranial cruciate ligament (CCL) throughout the stance phase. Rotation to a TPA of 5 degrees did not, however, substantially decrease the load in the CCL. Both procedures increased the load in the caudal cruciate ligament (CaCL). CONCLUSIONS: Cranial tibial thrust (CTT) is converted into caudal tibial thrust when the TPA is 0 degrees ; however, rotating the plateau to a TPA of 5 degrees does not eliminate the CTT. CLINICAL RELEVANCE: The TPLO procedure performed as currently recommended (rotating the tibial plateau to a TPA of 5 degrees) may not eliminate the CTT, but only reduce it. Both TPLO procedures evaluated here were found to increase the load in the CaCL.  相似文献   

20.
ObjectiveTo compare two echocardiographic methods of measuring aortic diameter in short-axis projections.MethodsRight-parasternal short-axis 2-dimensional projections of the left atrium and aorta were obtained from dogs and cats undergoing routine cardiac evaluation. Two investigators measured the aortic valve linear dimension using 2 methods: along the commissure between the non-coronary and right-coronary cusps and along the commissure between the non-coronary and left-coronary cusps. Inter-observer and intra-observer variability and agreement were assessed by comparing blinded measurements with each method by 4 trained observers on a standardized set of images. Measurements were compared for agreement using the limits of agreement analysis. Variability between observers was compared by examining residuals and intraclass correlation.Results274 canine and 100 feline aortic valve images were measured in the first part of the study. One observer demonstrated slight proportional bias, while the other observer showed more variability (less agreement). When results were pooled for both investigators, no bias was identified, and 95% limits of agreement were ±10% of the mean measurement for both species. In the second part of the study, 106 images were measured. Intraobserver variability was <4% for all observers. Inter-observer agreement was very high. Individual bias was identified in some observers, but was considered clinically inconsequential. Normalized differences between the 2 methods of measurement were below ±15% of the measured value for all observers.ConclusionsOur results show sufficient agreement between two common methods used to measure aortic linear dimensions to suggest that these methods are interchangeable.  相似文献   

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