Radiographic anatomy of the tarsocrural joint of the dog

The normal radiographic anatomy of the proximal hock joint of the dog is discussed. The choice of projection depended on the site to be examined. Examination of the lateral trochlear ridge of the talus required a number of projections including the fully extended and fully flexed mediolateral, plantaromedial-dorsolateral oblique and a flexed dorsoplantar using a horizontal beam. The best radiographic projection for examination of the medial side of the joint was the plantarodorsal projection while the mediolateral projection showed the dorsal and plantar edges and gave some general information of changes around the joint.     

Use of a flexed dorsoplantar radiographic view of the talocrural joint to evaluate lameness in two dogs.

A flexed dorsoplantar radiographic view of the talocrural joint was a useful additional view to diagnose abnormalities of the lateral trochlear ridge of the talus of 2 dogs. This view outlined the subchondral bone of both trochlear ridges of the talus and the apposing cochlea tibiae of the distal portion of the tibia. The tarsus was flexed at the level of the talocrural joint, and an x-ray beam was centered on the joint. With this additional view, fractures of the lateral trochlear ridge were readily diagnosed. This view would help to demonstrate osteochondral lesions of the lateral trochlear ridge.     

Evaluation of the Marsh Deer Stifle Joint by Imaging Studies and Gross Anatomy

This study aimed to evaluate the stifle joint of marsh deer using imaging studies and in comparison with gross anatomy. Ten hindlimbs from 5 marsh deer (Blastocerus dichotomus) were used. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed in each stifle joint. Two hindlimbs were dissected to describe stifle gross anatomy. The other limbs were sectioned in sagittal, dorsal or transverse planes. In the craniocaudal radiographic view, the lateral femoral condyle was broader than the medial femoral condyle. The femoral trochlea was asymmetrical. Subsequent multiplanar reconstruction revealed in the cranial view that the external surface of the patella was roughened, the medial trochlea ridge was larger than the lateral one, and the extensor fossa at the lateral condyle was next to the lateral ridge. The popliteal fossa was better visualized via the lateral view. Sagittal MRI images identified lateral and medial menisci, caudolateral and craniomedial bundles of cranial cruciate ligament, caudal cruciate ligament, patellar ligament and common extensor tendon. In conclusion, the marsh deer stifle presents some anatomical characteristics of the ovine stifle joint.     

134 Horses with osteochondritis dissecans of the tarso-crural joint: Clinical considerations and results following arthroscopic surgery

A retrospective study was performed on a sample of 134 horses diagnosed with osteochondritis dissecans (OCD) of the tarso-crural joints that underwent surgery for the removal of osteochondral fragments. Breed, age, site of the lesion, amount of synovial effusion and its resolution following surgery were evaluated.In more than 70 percent of cases the lesion involved the distal intermediate ridge of the tibia. The lateral trochlea ridge of the talus was involved in 6 percent of cases studied. OCD of the lateral trochlea ridge of the talus was frequently associated with OCD in other anatomical sites. Eighty-four percent of surgically treated cases that had post-op following returned to training exercise or racing activity.     

Rotation of the femoral trochlea for treatment of medial patellar luxation in a dog

A crossbreed dog was presented with non-weight bearing on the right hindlimb and a semi-flexed stifle. Clinical examination and radiographic investigation showed a grade 3 medial patellar luxation, characterised by hypoplasia of the medial trochlear ridge. No other significant skeletal abnormalities were detected. A 180 degrees rotation of the femoral trochlea was the surgical technique chosen to treat the trochlear dysplasia, the aim being to move the normal lateral ridge to the medial side and thereby prevent patellar luxation. This technique was able to restore correct conformation of the femoral trochlea and preserve the integrity of the trochlear groove cartilage, thus potentially retarding the progression of degenerative joint disease. The dog recovered fully and postoperative radiographic examinations showed healing of the rotated trochlea with only mild signs of degenerative joint disease.     

Osteochondritis dissecans of the lateral ridge of the trochlea of the tibial tarsal bone in the dog

The diagnosis and treatment of two cases of osteochondritis dissecans affecting the lateral ridge of the trochlea of the tibial tarsal bone is described. Radiographs taken in medio-lateral and oblique projections proved to be the most valuable for diagnosis. The lesions were treated surgically via a limited cranio-lateral approach. The lameness improved following surgery.     

Caudocranial horizontal beam radiographic projection for evaluation of femoral fracture and osteotomy repair in dogs and cats

A new radiographic projection of the femur was evaluated for use in the assessment of fracture or osteotomy repair in small animals. The view is obtained by directing the x-ray beam horizontally through the hind limb, from caudad to craniad, with the animal positioned in lateral recumbency, the hip flexed, and the stifle extended. Views obtained, using the new projection, were compared with the standard ventrodorsal views of the pelvis, with hind limbs extended. Osteotomy lines in the femoral shaft were significantly (P less than 0.01) more visible on the horizontal beam view. Significant difference was not evident in visibility of fracture lines between the 2 radiographic projections. The horizontal beam view was easily obtained, and equivalent to the standard ventrodorsal view for radiographic evaluation of femoral fracture and osteotomy repair.     

Morphology of the Pelvis and Hind Limb of the Red Panda (Ailurus fulgens) Evidenced by Gross Osteology,Radiography and Computed Tomography

The red panda (Ailurus fulgens) is a quadrupedal arboreal animal primarily distributed in the Himalayas and southern China. It is a species commonly kept in zoological collections. This study was carried out to describe the morphology of the pelvis and hind limb of the red panda evidenced by gross osteology, radiography and computed tomography as a reference for clinical use and identification of skeletons. Radiography of the pelvis and right hind limb was performed in nine and seven animals, respectively. Radiographic findings were correlated with bone specimens from three adult animals. Computed tomography of the torso and hind limb was performed in one animal. The pelvic bone had a wide ventromedial surface of the ilium. The trochlea of the femur was wide and shallow. The patella was similar to that seen in feline species. The medial fabella was not seen radiographically in any animal. The cochlea grooves of the tibia were shallow with a poorly defined intermediate ridge. The trochlea of the talus was shallow and presented with an almost flattened medial ridge. The tarsal sesamoid bone was always present. The lateral process of the base of the fifth metatarsal (MT) bone was directed laterally. The MT bones were widely spaced. The morphology of the pelvis and hind limb of the red panda indicated flexibility of the pelvis and hind limb joints as an adaptation to an arboreal quadrupedal lifestyle.     

Radiographic technique to improve diagnosis of sagittal axial sesamoid fracture in racing Thoroughbreds with lateral condylar fracture

The current study identified 124 lateral condylar fractures of the distal metacarpus or metatarsus over a 6-year period. Thirty of 124 lateral condylar fractures were classified as displaced. Eight of 30 displaced lateral condylar fractures and 1/86 incomplete lateral condylar fractures had concurrent sagittal axial fracture of the lateral proximal sesamoid bone. A 20-degree DMPLO view is the most sensitive radiographic projection to identify sagittal axial fracture of the lateral proximal sesamoid bone. A flexed 20-degree DMPLO projection demonstrates displacement of complete sagittal axial sesamoid fractures. Radiographic identification of axial sesamoid fracture is critical to provide the most accurate prognosis for return to racing. Arthroscopic assessment of the axial sesamoid fracture and cartilage injury on the lateral proximal sesamoid bone, as well as post-operative progression, are described in four surgical cases.     

Osteochondrosis of the Lateral Trochlear Ridge of the Talus in Seven Rottweiler Dogs

Eleven lesions of osteochondrosis in the lateral trochlear ridge of the talus were diagnosed in seven young Rottweiler dogs. Diagnosis was based on clinical and radiographic evaluations. Defects in the lateral trochlear ridge and osteochondral fragments arising from the dorsal and proximal margins of the ridge were visible radiographically. The dorsal 45 degrees lateral-plantaromedial oblique (D45 degrees L-P1MO) projection was the most useful in identifying the lesions. Exploratory arthrotomies were performed in six affected tarsi. In three cases, histologic examination revealed mineralized osteochondral fragments consistent with a diagnosis of osteochondrosis.     

Radiographic changes in elbow dysplasia following ulnar osteotomy--a case report and review of the literature

This case report describes the results of bilateral elbow arthrotomy and a unilateral ulnar osteotomy in a 10-month-old dog with bilateral elbow dysplasia. Fragmented coronoid processes were removed from both joints via bilateral medial arthrotomies. On the right side an ulnar osteotomy was also performed using a caudolateral approach. Bilateral flexed lateral elbow radiographs taken before surgery and 5 months postoperatively were assessed for changes in osteophyte size on the anconeal process, caudal epicondylar ridge and radial head. Osteophytes on the anconeal process and caudal epicondylar ridge disappeared over the postoperative period in the joint that received an ulnar osteotomy. In the contralateral joint the size of the oesteophytes on the anconeal process and caudal epicondylar ridge increased in size during the same period.     

Gross osteology and radiology of the pelvic limb of the adult small East African goat

The aim of this study was to provide the detailed normal gross osteology and radiographic anatomy of the pelvic limb in adult small East African goats as a reference for clinical use, biomedical research and teaching. Radiography of the pelvic limb was performed in five adult small East African goats. Bone specimens of four skeletally mature small East African goats were used for gross osteological study. The ilial wing was wide. The ischiatic tuberosity was prominent and well developed. The acetabulum was rounded. The minor trochanter was located caudomedially, and the femoral trochlea was deep and narrow. The lateral and medial condyles of the femur were approximately of the same size. The tibial tuberosity was prominent, and the cochlea grooves were deep with a pronounced intermediate ridge. The trochlea of the talus was deep. The patella presented a prominent tuberosity on the cranial surface. The metatarsal sesamoid bone was seen in all animals. The observed gross osteology and radiographic anatomy of the pelvic limb of small East African goats was consistent with the presence of strong extensor muscles of the hip, stifle and tarsus for propulsion during terrestrial walking and trotting.     

Radiographic assessment of humeroulnar congruity in a medium and a large breed of dog

Elbow joint incongruity is recognized as an important factor in the development, treatment, and prognosis of canine elbow dysplasia. Elbow incongruity has been measured based on radiographic joint space widths, however these values can be affected by the degree of elbow joint flexion. Recent studies have reported radiographic curvature radii as more precise measures of humeroulnar congruity in dogs. The aim of this prospective observational study was to describe radiographic curvature radii measured from flexed and extended elbow radiographs for a sample of dogs representing a medium breed (Portuguese Pointing Dog) and a large breed (Estrela Mountain Dog). The curvature radii from the ulnar trochlear notch and humeral trochlea were measured in 114 mediolateral elbow extended radiographic views (30 Portuguese Pointing Dog and 27 Estrela Mountain Dog), and 84 mediolateral flexed views (22 Portuguese Pointing Dog and 20 Estrela Mountain Dog). The sampled animals' ages ranged from 12 to 84 months (34.6 ± 17.8 months). Good agreement was observed between curvature radii measurements for flexed vs. extended views in both breed groups. Ulnar trochlear notch curvature radii measurements were greater than humeral trochlea curvature radii measurements in both breed groups. Both curvature radii were greater in the large‐breed dog group vs. the medium‐breed dog group. Both breed groups had ulnar and humeral curves with similar typology. However, the large breed group had greater intermediate differences between the humeroulnar surface curvature radii. Results from this study supported the use of curvature radii as measures of humeroulnar congruity in mediolateral flexed elbow radiographs of medium and large breed dogs.     

Radiographic, computed tomographic and arthroscopic findings in 23 dogs with osteochondrosis of the tarsocrural joint

Twenty-three dogs with osteochondrosis of the tarsocrural joint were evaluated by radiography, computed tomography (CT) and arthroscopy. The radiographic examination included an extended and flexed mediolateral, a plantarodorsal, a flexed dorsoplantar skyline view, and a plantaromedial-dorsolateral and a plantarolateral-dorsomedial view (two oblique views). The CT examination was carried out in ventral recumbency and 1 mm slices were taken with a bone window setting; 31 lesions were identified in the 46 joints examined. The arthroscopic exploration used either a plantar or a dorsal puncture, depending on the site of the lesion. In six cases the lateral, and in 17 cases the medial trochlear ridge was involved. Although the survey radiographs were sufficient to make a diagnosis, the CT examination helped to determine the exact site, and the number and size of the fragments of bone. A four-stage classification system comparable to the one used in man was established. Arthroscopy provided information about synovial inflammation and damage to the joint cartilage, and made it possible to remove fragments of bone from one-third of the cases.     

Arthroscopic Anatomy of the Equine Femoropatellar Joint and Approaches for Treatment of Osteochondritis Dissecans

Arthroscopic approaches to the femoropatellar joint were developed to determine their usefulness for evaluation and surgical treatment of osteochondritis dissecans. It was found that the articular cartilage of the lateral trochlear ridge, medial trochlear ridge, intertrochlear groove, patella, and the lateral and medial reflections of the joint capsule could be examined from an infrapatellar arthroscopic portal. The suprapatellar pouch could be examined partially. Lateral and medial instrument portals were evaluated to determine the accessibility of the lateral and medial trochlear ridges of the femur in the areas where osteochondritis dissecans lesions frequently occur. Sliding the arthroscope sleeve beneath the patella when entering the joint was associated with iatrogenic cartilage lesions. A new technique that directed the arthroscope lateral to the lateral trochlear ridge eliminated iatrogenic cartilage damage.     

INFLUENCE Of PATIENT POSITIONING ON THE L5–L6 MID-LAMINAR DISTANCE

The aim of this project was to determine the effect of patient position on the L5-L6 mid-laminar distance (MLD). The lumbar area of 22 recently euthanatized dogs of various breeds was radiographed in three positions: lateral recumbency with the spine in neutral position, lateral recumbency with the spine flexed in a kyphotic position, and sternal recumbency with the spine flexed in a kyphotic position. Digital images of the radiographs were analyzed using a computer program that allowed measurement of the MLD between L5-L6 in the three positions. The L5 and L6 MLD was significantly larger in sternal recumbency with the spine flexed (142.3 units) than both in lateral recumbency with the spine flexed (138.7 units; P= 0.001) and lateral recumbency with the spine in the neutral position (135.8 units; P < or = 0.001). The MLD in lateral recumbency with the spine flexed was significantly larger than in lateral recumbency with the spine in neutral position (P = 0.005). Positioning a dog in sternal recumbency with the spine flexed produces a significantly larger MLD than in lateral recumbency with the spine flexed; this should simplify needle placement when performing a lumbar puncture.     

The effect of parentage on the prevalence, severity and location of lesions of osteochondrosis in swine

The aims of this study were to determine the effects of parentage and gender on the prevalence, severity and location of lesions of osteochondrosis manifesta (OCM) and osteochondrosis dissecans (OCD) in offspring from different Norwegian Landrace boars and to examine the relationships between lesion characteristics and selected growth parameters. Fifteen sires were selected based on their high breeding value for osteochondrosis. Seven locations in the distal humerus and the distal femur from 1680 offspring of these animals were evaluated for severity of OCM and presence of OCD by gross examination of serially sectioned humeri and femora. Osteochondrosis manifesta was most prevalent in the trochlea of humerus, the sagittal ridge of humerus, the medial condyle of femur and the medial sulcus obliquus of femur. The severity of the lesions and the prevalence of OCD were highest in the trochlea and the sagittal ridge of humerus. Castrates had significantly higher OCM scores than sows. There were significant effects of both sire and dam on the OCM scores of the offspring in most locations; however, growth rate and weight at slaughter did not influence the OCM score.     

Diagnosis and surgical repair of patellar luxations in a flock of sheep

Eleven sheep with a common ancestry were evaluated for clinical signs of hind limb lameness. Physical examination revealed advanced forms of patellar luxation. Radiography confirmed the diagnosis of patellar luxation; flexed dorsoproximal-dorsodistal radiographic views were obtained and revealed hypoplasia of the femoral trochlea. Because of the advanced form of patellar luxation and trochlear hypoplasia, surgical intervention was recommended in the form of recession trochleoplasty and a modified tibial tuberosity transposition, along with imbrication and releasing incisions. Sheep may have a genetic predisposition for patellar luxation.     

Traumatic injuries associated with the short lateral collateral ligaments of the talocrural joint of the dog

Traumatic ruptures of the short parts of the lateral collateral ligament complex of the talocrural joint in the dog, or avulsion fractures of the origins of insertions of these ligaments on the distal fibula or the lateral talar trochlea are reported in six cases. The anatomy, physiology and pathophysiology of injuries to these ligaments and related structures are discussed. This type of injury has specific clinical and, or, radiographic features. Minor rotational instability can be detected if the fibulocalcanear or both ligaments are ruptured, while disruption of only the fibulotalar ligament or its insertions cause no apparent instability. Clinical diagnosis of ligamentar ruptures often requires manual examination of the stressed joint under general anaesthesia. Radiographic diagnosis of avulsion fractures requires inclusion of oblique views. Avulsion fractures of the lateral talar trochlea produced relatively large loose fragments situated proximally. Any possible relation between osteochondritis dissecans and the avulsion fractures could not be evaluated. Reconstructive surgical therapy is advocated. Prognosis for return to full function seems fair to good.