Good Inter- and Intra-Observer Reliability for Assessment of Radiographic Femoral and Tibial Frontal and Sagittal Planes Joints Angles in Normal Cats.

OBJECTIVE: The aim of this study was to evaluate the inter- and intra-observer reliability of plain digital radiographs for assessing normal feline femoral and tibial joint reference angles in the sagittal and frontal planes. STUDY DESIGN: This was a cadaveric radiographic anatomical study. that involved 20 short-haired domestic adult cats. MATERIALS AND METHODS: Sagittal and frontal plane tibial and femoral joint angles of 40 limbs were measured twice by three observers with different levels of experience. Inter- and intraobserver reliability was determined by the intra-class correlation coefficient (ICC). An ICC > 0.75 was considered high correlation, 0.74 > ICC > 0.60 good correlation, 0.59 > ICC > 0.4 fair correlation and an ICC < 0.40 poor correlation. RESULTS: Mean ± standard deviation angles were anatomic lateral proximal femoral angle (aLPFA) 110.6 ± 3.6; anatomic lateral distal femoral angle (aLDFA) 91.9 ± 2.1; mechanical lateral proximal femoral angle; mLPFA (mLPFA) 107.3 ± 3.6; mechanical lateral distal femoral angle (mLDFA) 95.5 ± 1.7; femoral neck anteversion (FNA) 121.9 ± 4.1; anatomical caudal proximal femoral angle (aCPFA) 156.1 ± 3.9; anatomical caudal distal femoral angle (aCDFA) 101.4 ± 1.4; mechanical medial proximal tibial angle (mMPTA) 93.5 ± 1.2; mechanical medial distal tibial angle (mMDTA) 100.5 ± 2.3; mechanical cranial proximal tibial angle (mCrPTA) 113.1 ± 3.2; tibial plateau angle (TPA) 23.1 ± 3.2; mechanical cranial proximal tibial angle (mCrDTA) 86.7 ± 3.1.The intra-observer ICC indicated high correlation for 70% or more of the measurements. The inter-observer agreement among observers was high. These results show that the radiographic method for measuring femoral and tibial joint angles was good or high, except for FNA and mCrDTA. CONCLUSIONS: This study provides some radiographic anatomical and mechanical joint angles of the femurs and tibias of normal domestic short-haired cats. We found good reliability for both intra- and interobserver measurements.

Assessment of T2 Relaxation Times for Normal Canine Knee Articular Cartilage by T2 Mapping Using 1.5-T Magnetic Resonance Imaging.

Objectives This study aims to assess and compare the T2 relaxation times for articular cartilage of normal canine stifle joints in four regions by T2 mapping using a 1.5-T magnetic resonance imaging (MRI). Methods In vivo prospective study: 20 hindlimbs (left and right) from 10 normal healthy beagle dogs (n = 20). The region of interest (ROI) was subdivided into medial and lateral condyles of femoral cartilage (MF and LF, respectively) and medial and lateral condyles of tibial cartilage (MT and LT, respectively). The T2 relaxation times were assessed in regions where the cartilage thickness was greater than 0.5 mm. Results The median maximum cartilage thickness (mm) of the four ROI were 0.7 (range: 0.9-0.6), 0.6 (range: 0.7-0.5), 0.7 (range: 0.9-0.5) and 0.6 (range: 0.8-0.5) at MF, LF, MT and LT, respectively. The errors in the measurement (%) of the four ROI were 64.3 (range: 50.0-75.0), 75.0 (range: 64.3-90.0), 64.3 (range: 20.0-90.0) and 75.0 (range: 56.3-90.0) at MF, LF, MT and LT, respectively. The median T2 relaxation times (ms) for the articular cartilage of the four ROI were 70.2 (range: 57.9-87.9), 57.5 (range: 46.8-66.9), 65.0 (range: 52.0-92.0) and 57.0 (range: 49.0-66.2) at MF, LF, MT and LT, respectively. The inter-observer correlation coefficient (ICC, 2.1) for the T2 relaxation times of MF was 0.644. Clinical Significance This study offers useful information on T2 relaxation times for articular cartilage of the stifle joint using a 1.5-T MRI in normal dogs.

Assessment of novel digital and smartphone goniometers for measurement of canine stifle joint angles.

OBJECTIVE To evaluate accuracy and reliability of 3 novel goniometers for measurement of canine stifle joint angles and compare the results with those obtained with a universal goniometer (UG). SAMPLE 8 pelvic limbs from 4 canine cadavers. PROCEDURES Each limb was secured to a wooden platform at 3 arbitrarily selected fixed stifle joint angles. Goniometry was performed with 2 smartphone-based applications (novel goniometers A and B), a digital goniometer (novel goniometer C), and a UG; 3 evaluators performed measurements in triplicate for each angle with each device. Results were compared with stifle joint angle measurements on radiographs (used as a gold standard). Accuracy was determined by calculation of bias and total error, coefficients of variation were calculated to estimate reliability, and strength of linear association between radiographic and goniometer measurements was assessed by calculation of correlation coefficients. RESULTS Mean coefficient of variation was lowest for the UG (4.88%), followed by novel goniometers B (7.37%), A (7.57%), and C (12.71%). Correlation with radiographic measurements was highest for the UG (r = 0.97), followed by novel goniometers B (0.93), A (0.90), and C (0.78). Constant bias was present for all devices except novel goniometer B. The UG and novel goniometer A had positive constant bias; novel goniometer C had negative constant bias. Total error at 50° and 100° angles was > 5% for all devices. CONCLUSIONS AND CLINICAL RELEVANCE None of the devices accurately represented radiographically measured stifle joint angles. Additional veterinary studies are indicated prior to the use of novel goniometers in dogs.

Indirect assessment of stifle angle for improved accuracy of preoperative planning of tibial osteotomy procedures in dogs.

To assess reliability of the mechanical axes stifle angle in dogs positioned for radiography with a neutral stifle (neutral stifle angle (nSA)). To investigate radiographic landmarks for assessment of nSA from a collimated radiographic view. One hundred radiographs were taken of normal stifles belonging to 55 skeletally mature medium and large breed dogs, positioned using a repeatable protocol. Radiographs were widely collimated to include the femoral head and the talus. The angle of Blumensaat's line through the intercondylar fossa relative to the Mechanical Axis of the femur (intercondylar fossa angle, IFA), the angle of inclination of a tibial crest tangent line relative to the Mechanical Axis of the tibia (tibial crest angle, TCA) and the tibial plateau angle (TPA) were recorded. Mean nSA was 133.5°. Mean IFA was 155.5°. TCA had a mean of 6.7°. Estimates for nSA were calculated using mean IFA combined with mean TCA (enSA1), mean TPA (enSA2) and the mechanical axis of the tibia (enSA3). Mean percentage error relative was 2.99 per cent for enSA1, 2.82 per cent for enSA2, 1.67 per cent for enSA3. Blumensaat's line provides a consistent radiological feature for assessment of nSA. Assessment of nSA and correction for values varying from 135° may allow more consistent and accurate measurement of patellar tendon angle for presurgical planning.

Radiographic, ultrasonographic, and anatomic assessment of femoral trochlea morphology in red foxes (Vulpes vulpes).

OBJECTIVE: To compare repeatability and equivalency of measures of femoral trochlea depth and trochlear angle in red foxes (Vulpes vulpes) determined by use of radiography, ultrasonography, and digital photography of cadaver limbs. SAMPLE: 24 pelvic limbs from 12 red fox cadavers. PROCEDURES: Cranioproximal-craniodistal oblique (skyline) and lateromedial radiographic views of the stifle joint and ultrasonographic images at 5 locations along the femoral trochlea were used in the study. Spacing of the 5 locations was determined on the basis of patellar position with the stifle joint at various caudal angles ranging from 96° to maximal extension (approx 170°). Ultrasonographic measurements were compared with those obtained at matched locations on photographs of anatomic preparations. Trochlear depth was assessed with all 3 image formats, and trochlear angle (measured between the trochlear ridges and sulcus) was assessed on radiographs and ultrasonographic images. Patellar thickness was measured on radiographs. Values obtained were compared by means of ANOVA, modified Bland-Altman plots, and repeatability testing. RESULTS: Depth measurement repeatability was considered good for all modalities. Small but significant differences between mean ultrasonographic trochlear depth and anatomic (photographic) measurements were found at 3 locations; 95% limits of agreement for paired anatomic and ultrasonographic measurements were wide. The ratio of trochlear depth to radiographic patellar thickness was approximately 30% for all modalities. Trochlear angle measurements were more variable than trochlear depth measurements, especially in the distal aspect of the trochlea. CONCLUSIONS AND CLINICAL RELEVANCE: Paired anatomic and ultrasonographic measurements did not appear equivalent in this study, possibly attributable to imprecise probe location, which could limit quantitative use of ultrasonography in assessing proximal trochlear depth in a clinical setting.

Morphometric assessment of the proximal portion of the tibia in dogs with and without cranial cruciate ligament rupture.

Based on the clinical observation that dogs with a steep tibial plateau slope had variable tibial morphology, we hypothesized that these dogs could be further characterized using measurements developed by examining computer generated models of specific proximal tibial malformations. A 3D tibial model was created from a normal canine tibia. The model was manipulated to reproduce two specific proximal tibial anomalies representing deformities originating from the tibial plateau or the proximal tibial shaft. Data from these models were used to create specific measurements that would characterize the shape of these anomalies. These measurements included the diaphyseal tibial axis (DTA)/proximal tibial axis (PTA) angle, which defined the orientation of the proximal portion of the shaft in relation to the tibial mid-shaft. These measurements were then made on radiographs of dogs with and without cranial cruciate ligament (CCL) rupture. Models with tibial plateau and proximal shaft deformities had a steep tibial plateau slope (TPS). Models with proximal shaft deformity had a markedly increased DTA/PTA angle. The model with a 10 degree proximal shaft deformity had a DTA/PTA angle of 11.23 degrees. Six dogs (9.0%) had a DTA/PTA angle larger than 11.23 degrees (range, 11.4-13.9 degrees). Dogs in this group had ruptured CCL and a steep TPS. Dogs with CCL rupture had higher TPS (mean, 31.8 +/- 4.1 degrees) and DTA/PTA angle (mean, 6.0 +/- 3.3 degrees) than dogs without CCL rupture (means, 23.6 +/- 3.4 degrees and 4.1 +/- 2.2 degrees, respectively). Dogs with proximal shaft deformity represented a distinct group, which could not be identified using the magnitude of the TPS alone. Characterizing more precisely the shape of the proximal portion of the tibia in dogs contributes to our understanding of the pathogenesis of steep TPS and may facilitate the optimization of the surgical management of dogs with CCL rupture.

Radiographic changes in Thoroughbred yearlings. Part 2: Associations with racing performance.

REASONS FOR PERFORMING STUDY: Although the radiographic examination of yearlings has become commonplace at some large Thoroughbred sales, there are few data to support the decisions facing veterinarians who are asked to evaluate future racing potential. OBJECTIVES: To identify radiographic changes in the fetlocks, proximal sesamoid bones, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings associated with future racing performance during ages 2 and 3 years. METHODS: Radiographs from routine pre- and post sale examinations of 1162 yearlings were used to identify individual radiographic changes in sale yearlings. Starting a race, the percent of starts placed, money earned and earnings per start were used to assess racing performanceand examined for associations with the radiographic changes observed. RESULTS: Overall 946 (81%) yearlings started at least one race during ages 2 or 3 years. Fourteen of 24 (58%) yearlings with moderate or extreme palmar supracondylar lysis of the third metacarpus, 8 of 14 (57%) of those with enthesophyte formation on the proximal sesamoid bones and 19 of 30 (63%) of those with dorsal medial intercarpal joint disease started a race. The odds of starting a race when age 2 or 3 years were 3 times lower for yearlings with these changes (P < 0.01) compared with yearlings that did not have these changes. Twenty-five of 36 (69%) yearlings with proximal dorsal fragmentation of the first phalanx in the hind fetlock started a race and these yearlings were also less likely (OR = 0.51, P = 0.07) to start a race. Yearlings with enthesophyte formation on hind proximal sesamoid bones placed in a smaller percentage of starts (16%, P = 0.01) earned less money (987 US dollars, P = 0.02) and had lower earnings per start (252 US dollars, P = 0.03) compared to starters without this change. CONCLUSIONS: Although many of the changes observed on radiographs of sale yearlings do not appear to influence future racing performance, some are associated with reduced performance. POTENTIAL RELEVANCE: The results of this study are best applied in parallel with the clinical impressions of veterinarians experienced in examining radiographs of sale yearlings. Some findings support those established in the literature as incidental findings and others suggest new areas for concern not previously reported as a problem in Thoroughbred sale yearlings.