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.

Assessment of the efficacy of intra-articular platelet rich plasma treatment in an ACLT experimental model by dynamic contrast enhancement MRI of knee subchondral bone marrow and MRI T2∗ measurement of articular cartilage.

OBJECTIVE: The vascularization of subchondral bone plays a significant role in the progression of knee osteoarthritis (OA). Treatment with platelet-rich plasma (PRP) has positive effects on cartilage lesions. However, PRP's efficacy for subchondral bone marrow lesions and the relationship of these lesions to cartilage are still undiscovered. Therefore, our aims were first to longitudinally investigate the change in subchondral flow by dynamic contrast enhanced MRI and degeneration of cartilage by MRI T2∗ in an anterior cruciate transection rodent (ACLT) model, and second to examine changes in parameters after intra-articular PRP injection. DESIGN: A 32-week investigation in 18 rats allocated to sham-control, ACLT with normal saline injection (ACLT + NS), and ACLT with PRP injection groups ended with histological evaluation. Another rat was used as a donor of allogenic PRP. RESULTS: Compared to the sham-control group, the ACLT + NS group had higher subchondral blood volume A (0.051, 95% confidence interval: 0.009, 0.092) and lower venous washout kel (-0.030: -0.055, -0.005) from week 4; lower permeability kep from week 18 (-0.954: -1.339, -0.569); higher cartilage T2∗ values (1.803: 1.504, 2.102) reflecting collagen loss beginning at week 10. For the PRP treatment group, subchondral bone marrow A and cartilage T2∗ decreased from week 10. Histological results confirmed and were correlated with the MRI findings. CONCLUSION: Subchondral hyper-perfusion plays a vital role in the pathogenesis of OA and was associated with cartilage degeneration. The efficacy of PRP can be observed from reduced perfusion and MRI T2∗ values.

Computed Tomographic Assessment of Block Recession Trochleoplasty and Partial Parasagittal Patellectomy in Cats.

OBJECTIVE: The aim of this study was to assess computed tomography (CT) images of cadaveric feline stifles and record the relationship between the patella and femoral trochlea in normal stifles; then to investigate the effect of block recession trochleoplasty (BRT) with and without partial parasagittal patellectomy (PPP) on patellofemoral contact, depth of patellar recession and size of trochlea and patella. MATERIALS AND METHODS: The sample population included six cat cadavers (12 stifles). Preoperative CT scans with stifles in three positions: extended (155-165°), neutral (85-95°) and flexed (35-45°). Lateral stifle arthrotomy was followed by BRT. CT scans were taken as above. PPP was performed so the width of the patella was 1 mm narrower than the BRT. CT scans were repeated and CT measurements were taken. RESULTS: The area of contact between the patella and femoral trochlea was significantly reduced after BRT and then significantly increased after PPP. The depth of patellar recession was unchanged after BRT, but then was significantly higher after PPP. The patella was wider than the trochlea preoperatively and post-BRT and narrower post-PPP. Reduction in bone volume following PPP (mean: 20%) was 50% the reduction in patella width (mean: 40%). CONCLUSION: Block recession trochleoplasty did not improve patellar recession and decreased patellofemoral contact area. Following BRT, the patella rides the trochlear ridges and loses contact with the trochlear sulcus. Block recession trochleoplasty alone should not be performed in cats. Instead, BRT should be combined with PPP.

Radiographic Assessment of the Popliteal Lymph Node to Aid the Differentiation of Canine Stifle Osteosarcoma From Moderate to Severe Stifle Degenerative Joint Disease.

Degenerative joint disease of the stifle is a common canine osseous pathology. Early degenerative changes may show mild mineral proliferation of periarticular margins with soft tissue, resulting in joint distension. If the joint is chronically unstable, osseous changes become more complex. Moderate to severe stifle degenerative disease then transitions to a combination of bony proliferation and resorption as subchondral cystic changes develop. The radiographic descriptions of moderate to severe degenerative disease overlap with those of subtle aggressive disease. If this occurs in a location prone to primary bone tumors, like the distal femur, radiographic interpretation becomes difficult. The aim of this study was to evaluate the utility of objectively assessing the popliteal lymph node size and shape on radiographs to differentiate moderate to severe stifle degenerative joint disease from distal femoral or tibial osteosarcoma. Stifle radiographs were acquired for evaluation of pelvic lameness localized to the stifle joint. Dogs with moderate to severe degenerative stifle joint disease were radiographed at 3 time points: prior to surgery for a tibial plateau leveling osteotomy (103), immediately postoperation (103), and at a recheck 6-8 weeks postsurgery (62). Dogs with osteosarcoma were radiographed only at time of diagnosis (42). Length and width gross popliteal lymph node measurements and a ratio of long axis to short axis were compared between groups using nonparametric analysis. No significant difference was determined using a long axis to short axis ratio for the popliteal lymph node to differentiate moderate to severe stifle degenerative joint disease and osteosarcoma (P = .290). The gross measurements of the long axis and short axis of the popliteal lymph node for dogs with osteosarcoma were significantly greater than the degenerative joint disease groups (P = .017, P = .000). Thus, evaluation of a long axis to short axis ratio for popliteal lymph nodes does not provide a clinically useful objective measure in differentiating peristifle osteosarcoma from moderate to severe degenerative disease of the stifle joint. The length and width of the popliteal lymph node differed significantly; however, the clinical difference is minimal.

Ex vivo preliminary investigation of radiographic quantitative assessment of cranial tibial displacement at varying degrees of canine stifle flexion with or without an intact cranial cruciate ligament.

BACKGROUND: The presence of cranial tibial subluxation can aid in the detection of joint instability as a result of CrCL injury. Detection of cranial tibial subluxation has been described using the tibial compression test (TCT) and cranial drawer test (CDT); however, diagnosis of CrCL insufficiency by assessing cranial subluxation motion of the tibia is subjective and difficult to quantify accurately. The aim of this study was to investigate a measurement technique to assess the degree of cranial tibial displacement relative to the femoral condyles on mediolateral projection stifle radiographs at varying degrees of stifle flexion (90°, 110°, and 135°) in CrCL intact, partially, and completely transected conditions. Radiographic measurements included: CrCL length and intercondylar distance (ICD), defined as the distance between the tibial mechanical axis (TMA) and the femoral condylar axis (FCA). The influence of CrCL status, stifle flexion angle, and measurement type on measured distance was evaluated. The relationship between CrCL length and ICD measurement was also assessed. RESULTS: Complete transection of the CrCL resulted in significant cranial tibial displacement. Stifle flexion angle affected ICD, but not CrCL length. Normalized measured CrCL length and ICD were significantly different; however, no differences existed between the change in distance detected by CrCL length and ICD measurements as CrCL transection status changed. Correlation coefficients detected a significant positive correlation between measured CrCL and ICD. CONCLUSION: The ICD measurement technique was able to quantify tibial displacement at various stifle flexion angles in the intact and completely transected CrCL conditions. The ICD measurement was more affected by stifle flexion angle than was the CrCL length.

Magnetic Resonance Imaging Assessment of Intra-Articular Structures in the Canine Stifle Joint after Implantation of a Titanium Tibial Plateau Levelling Osteotomy Plate.

OBJECTIVES: To determine the effectiveness of magnetic resonance imaging (MRI) in the evaluation of anatomical stifle structures with respect to implant positioning after tibial plateau levelling osteotomy (TPLO) using a titanium plate. METHODS: Selected sagittal and dorsal sequences of pre- and postoperative MRI (1.0 T scanner) of 13 paired (n = 26) sound cadaveric stifle joints were evaluated. The effect of susceptibility artifact on adjacent anatomical stifle structures was graded from 0 to 5. The impact of implant positioning regarding assessment score was calculated using Spearman's rank correlation coefficient. RESULTS: Sagittal turbo spin echo (TSE)-acquired images enabled interpretation of most soft tissue, osseous and cartilage structures without detrimental effect of susceptibility artifact distortions. In T2-weighted TSE images, the cranial cruciate ligament and caudal horn of the medial meniscus could be evaluated, independent of implant position, without any susceptibility artifact in all specimens. T2-weighted fast field echo, water selective, balanced fast field echo and short tau inversion recovery were most markedly affected by susceptibility artifact. CLINICAL SIGNIFICANCE: In selected TSE sequences, MRI allows evaluation of critical intra-articular structures after titanium TPLO plate implantation. Further investigations with confirmed stifle pathologies in dogs are required, to evaluate the accuracy of MRI after TPLO in clinical cases in this context.

The robustness of T2 value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI.

PURPOSE: To evaluate the robustness of MR transverse relaxation times of trabecular bone from spin-echo and gradient-echo acquisitions at multiple spatial resolutions of 7 T. METHODS: The effects of MRI resolutions to T2 and T2* of trabecular bone were numerically evaluated by Monte Carlo simulations. T2 , T2*, and trabecular structural indices from multislice multi-echo and UTE acquisitions were measured in defatted human distal femoral condyles on a 7 T scanner. Reference structural indices were extracted from high-resolution microcomputed tomography images. For bovine knee trabecular samples with intact bone marrow, T2 and T2* were measured by degrading spatial resolutions on a 7 T system. RESULTS: In the defatted trabecular experiment, both T2 and T2* values showed strong ( |r| > 0.80) correlations with trabecular spacing and number, at a high spatial resolution of 125 µm3 . The correlations for MR image-segmentation-derived structural indices were significantly degraded ( |r| < 0.50) at spatial resolutions of 250 and 500 µm3 . The correlations for T2* rapidly dropped ( |r| < 0.50) at a spatial resolution of 500 µm3 , whereas those for T2 remained consistently high ( |r| > 0.85). In the bovine trabecular experiments with intact marrow, low-resolution (approximately 1 mm3 , 2 minutes) T2 values did not shorten ( |r| > 0.95 with respect to approximately 0.4 mm3 , 11 minutes) and maintained consistent correlations ( |r| > 0.70) with respect to trabecular spacing (turbo spin echo, 22.5 minutes). CONCLUSION: T2 measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high-resolution 3D micro-MRI is difficult to obtain.

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.

Accuracy of computed tomographic arthrography for assessment of articular cartilage defects in the ovine stifle.

Articular cartilage defects are one of the features of osteoarthritis in animals and humans. Early detection of cartilage defects is a challenge in clinical veterinary practice and also in translational research studies. An accurate, diagnostic imaging method would be desirable for detecting and following up lesions in specific anatomical regions of the articular surface. The current prospective experimental study aimed to describe the accuracy of computed tomographic arthrography (CTA) for detecting cartilage defects in a common animal model used for osteoarthritis research, the ovine stifle (knee, femoropatellar/femorotibial) joint. Joints in cadaver limbs (n = 42) and in living animals under anesthesia (n = 13) were injected with a contrast medium and imaged using a standardized CT protocol. Gross anatomy and histological assessment of specific anatomic regions were used as a gold standard for the evaluation of sensitivity, specificity, negative predictive value, and positive predictive value for CTA identification of articular cartilage defects in those regions. Pooled estimated sensitivity and specificity were 90.32% and 97.30%, respectively, in cadaver limbs, and 81.82% and 95.24%, respectively, in living animals. Pooled estimated positive predictive value and negative predictive values were 98.25% and 85.71%, respectively, in cadaver limbs, and 81.82% and 95.24%, respectively, in living animals. The delineation of cartilage surface was good for anatomical regions most frequently affected by cartilage defects in the ovine stifle: medial femoral condyle, medial tibial condyle, and patella. This study supported the use of CTA as an imaging technique for detecting and monitoring articular cartilage defects in the ovine stifle joint.

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.

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

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

Radiographic changes in Thoroughbred yearlings in South Africa.

This study involves the evaluation of pre-purchase radiographic studies of South African Thoroughbred yearlings. Radiographic changes were recorded and compared with similar international studies. The study differs from other studies in that a lower prevalence of pedal osteitis (1.26%), dorsal osteochondral fragmentation of the metatarsophalangeal joint (1.60%), distal metacarpal sagittal ridge changes (15.7%), ulnar carpal bone lucencies (8.33%), carpal osteophytes (1.19%), distal intertarsal and tarsometatarsal joint radiographic changes (9.92%), tarsal osteochondrosis lesions (4.40%) and stifle osteochondrosis lesions (0.4%) was found. The prevalence of dorsal osteochondral fragments in the metacarpophalangeal joint was similar to other studies (1.60%). A higher prevalence of vascular channels as well as irregular borders and lucencies was evident in the proximal sesamoid bones. There was a higher prevalence of palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments (2% and 7.10% respectively). Palmar metacarpal disease, metacarpal supracondylar lysis, proximal sesamoid bone fractures and carpal osteochondral fragmentation were absent in the current study. Additional findings recorded in the current study were proximal interphalangeal joint hyperextension (left front 15.13%, right front 18.91%), the solar angle (right front 2.38 degrees, left front 2.79 degrees), the prevalence of carpal bone 1 (30.95%) and carpal bone 5 (1.59%). Management, nutrition and genetics in the various groups of Thoroughbred yearlings should be further investigated in order to explain the reasons for the differences recorded in the current study.

Prevalence of various presale radiographic findings and association of findings with sales price in Thoroughbred yearlings sold in Kentucky.

OBJECTIVE: To estimate prevalences of various presale radiographic findings and of presale arthroscopy in horses offered for sale at the 2006 Keeneland September yearling sale and to compare sales prices between yearlings with and without various presale radiographic findings or a history of arthroscopy. ANIMALS: 397 Thoroughbred yearlings. DESIGN: Cross-sectional study. PROCEDURES: Presale radiographs and health records were examined to estimate prevalences of various radiographic findings and presale arthroscopy. Sales price records were used to compare sales prices between yearlings with and without various presale radiographic findings or a history of arthroscopy. RESULTS: In the forelimbs, the most common radiographic findings were vascular channels in the proximal sesamoid bones (23%), enthesophytes or osteophytes in the radiocarpal joint (22%), and osteochondritis lesions involving the sagittal ridge of the third metacarpal bone (20%). In the hind limbs, the most common radiographic findings were enthesophytes or osteophytes involving the proximal sesamoid bones (39%), abnormalities of the distodorsal aspect of the third metatarsal bone (36%), enthesophytes or osteophytes involving the distal intertarsal joint (27%), and osteochondritis lesions involving the stifle joint (8%). Thirteen percent of horses had a history of presale arthroscopy. Median sales price was significantly lower in horses with fragments of the proximal phalanx than in horses without. Median sales price was significantly higher in horses with a history of presale arthroscopy than in horses without. CONCLUSIONS AND CLINICAL RELEVANCE: Results revealed significant associations between a diagnosis of fragments of the proximal phalanx, presale arthroscopy, and sales price in Thoroughbred yearlings.

Canine stifle positive contrast computed tomography arthrography for assessment of caudal horn meniscal injury: a cadaver study.

OBJECTIVE: To investigate the use of computed tomography (CT) arthrography in cadaveric canine stifles with particular emphasis on the diagnosis of meniscal injury. STUDY DESIGN: Prospective cadaver study. SAMPLE POPULATION: Pelvic limbs from adult Beagles (n=10). METHODS: After survey CT scan of each stifle oriented in the dorsal plane, positive contrast stifle CT arthrogram (CTA) was performed using the same slice orientation. Each stifle was then randomly allocated into 1 of 2 treatment groups: group A--arthrotomy, cranial cruciate ligament (CCL) transection and simulated injury to the caudal horn of the medial meniscus; group B--arthrotomy and CCL transection only. CT scan was repeated as before and post-arthrotomy images were interpreted by a radiologist unaware of treatment grouping. RESULTS: The cranial and caudal cruciate ligaments, medial and lateral menisci, menisco-femoral ligament, and long digital extensor tendon were all identifiable on CTA images. CTA was 90% sensitive and 100% specific for diagnosing simulated caudal horn meniscal injury. CONCLUSIONS: Stifle CTA enables identification of intra-articular structures within the stifle and is a reliable method for identifying simulated meniscal injuries in a cadaver model. CLINICAL RELEVANCE: CTA imaging of the canine stifle has potential clinical value for detection of meniscal injury.

Radiographic assessment of the progression of osteoarthrosis in the contralateral stifle joint of dogs with a ruptured cranial cruciate ligament.

The formation and progression of osteoarthrosis in the unaffected contralateral stifle joints of 14 dogs with a unilateral cranial cruciate ligament rupture were monitored radiographically in terms of a global score and the scores for 10 parameters specific for the stifle joint. The dogs were examined initially and six and 12 months later by three observers, and the variability between the observers' scores was also assessed. The score for osteophytes at the tibial attachment site of the ligament was the most reliable parameter, and that for the increase in femoropatellar joint space was the least reliable. In the contralateral stifle joints there were significant increases after six and 12 months in osteophyte formation caudal to the tibial plateau, and in subchondral sclerosis of the tibial plateau and of the long digital extensor muscle groove. These three parameters progressed more regularly during the disease process than the other parameters. The global osteoarthrosis score of the contralateral stifle joint was an important risk factor for sustaining a rupture of the cranial cruciate ligament in that joint during the next six months.

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 1: Prevalence at the time of the yearling sales.

REASONS FOR PERFORMING STUDY: Radiography in presale examinations of TB yearlings has become standard practice in recent years. OBJECTIVES: To describe the prevalence and distribution of radiographic changes in the fetlocks, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings in central Kentucky when these joints were examined as part of routine pre- and post sale evaluations. METHODS: Horses subjected to radiographs included the fore (n = 1127) and hind (n = 1102) fetlocks, carpi (n = 1130), tarsi (n = 1101), stifles (n = 660) and fore feet (n = 300). Radiographic changes were categorised by location and type of change present (e.g. lucency, fragment) for each series. RESULTS: In the fore fetlocks 1.6% had fragmentation of the proximal dorsal first phalanx and 0.5% fragmentation of the proximal palmar aspect. In the hind fetlocks 5.9% had fragmentation at the plantar aspect and 3.3% fragmentation dorsally. Lucencies, fragments or loose bodies were detected at the dorsal aspect of the distal third metacarpus in 2.8% and, at the same location on the third metatarsus, 3.2%. Most yearlings (98%) had vascular channels in the proximal sesamoid bones and irregular vascular channels (> 2 mm wide or with nonparallel sides) were more common (79%) than regular vascular channels (56%). The intermediate ridge of the distal tibia was the most common location for fragmentation in the tarsus (4.4%). CONCLUSIONS: While some radiographic changes, e.g. vascular channels in proximal sesamoid bones, are very common in Thoroughbred yearlings, others, e.g. fragmentation or subchondral lucency within joints are quite rare usually affecting less than 5% of the population. POTENTIAL RELEVANCE: Veterinarians should expect to find radiographic changes in Thoroughbreds presented for examination prior to the yearling sales. The rarity of some changes thought to affect soundness or racing performance will make further invesigation of these conditions in horses without clinical signs more difficult.