Microfocal radiography as an aid to the diagnosis of canine elbow osteochondrosis

Computed tomography of the elbow joint in clinically normal dogs

OBJECTIVE

To use computed tomography (CT) to provide a detailed description of elbow joint structures in clinically normal dogs.

ANIMALS

6 clinically normal adult mixed-breed dogs weighing 24 to 37 kg and one 12-month-old Labrador Retriever weighing 27 kg.

PROCEDURE

To perform CT of both elbow regions, dogs were anesthetized and placed in lateral recumbency. One- and 2-mm contiguous slices were obtained by use of a third generation computed tomographic scanner. Good resolution and anatomic detail were acquired from the computed tomographic images by use of a bone (window width, 3,500 Hounsfield units; window level, 500 Hounsfield units) and soft-tissue setting (window width, 400 Hounsfield units; window level, 66 Hounsfield units). After euthanasia, the forelimbs from the Labrador Retriever were removed and frozen in water at -18 degrees C. Elbow joints were sectioned into approximately 1-mm-thick slab sections by use of an electric planer. Anatomic sections were photographed and compared with the corresponding computed tomographic images. Computed tomographic reconstructions of the elbow joint were created in sagittal and dorsal planes.

RESULTS

Structures on the computed tomographic images were matched with structures in the corresponding anatomic sections. The entire humeroradioulnar joint surface could be evaluated on the reconstructed images in the sagittal and dorsal plane.

CONCLUSIONS AND CLINICAL RELEVANCE

Computed tomographic images provide full anatomic detail of the bony structures of the elbow joint in dogs. Muscles, large blood vessels, and nerves can also be evaluated. These results could be used as a basis for evaluation of computed tomographic images of the forelimbs of dogs with elbow joint injuries.

Computed tomographic osteoabsorptiometry of the elbow joint in clinically normal dogs

OBJECTIVE

To evaluate subchondral bone density patterns in elbow joints of clinically normal dogs by use of computed tomographic (CT) osteoabsorptiometry.

SAMPLE POPULATION

20 cadaver forelimbs from 10 clinically normal dogs.

PROCEDURE

Each elbow joint was imaged in parasagittal and transverse planes of 1.5-mm thickness. Slice data were converted to dipotassium phosphate equivalent density (PPED) values. Sagittal, parasagittal, and transverse medial coronoid process topographic maps were constructed. Defined zones were created for each of the 3 CT planes, and confluence and peak PPED values were determined.

RESULTS

The lowest PPED value was 340 mg/ml (articular and subchondral confluence), and the highest was 1780 mg/ml (peak subchondral density). Detectable effects of joint laterality were not found in the confluence or peak PPED measurements or in the peak-to-confluence PPED ratio for all 3 CT planes. Significant differences were found among zones in all 3 planes for confluence and peak PPED measurements and between sagittal and transverse planes for peak-to-confluence PPED ratios. Subjectively, the pattern of density distribution among dogs was fairly consistent for the sagittal and parasagittal slices. Three specific patterns of density distribution were apparent on the transverse topographic maps of the medial coronoid process that corresponded to conformational differences.

CONCLUSIONS AND CLINICAL RELEVANCE

The use of CT osteoabsorptiometry provides a repeatable technique that can be used to noninvasively examine bone density and the effects of stress acting on joints in vivo. Variability in density values for any of the CT planes was not identified among clinically normal dogs.

Diagnostic imaging of osteochondrosis

This article includes imaging of the glenohumeral (shoulder), elbow, stifle, and tarsal joints. The imaging modalities discussed are survey radiography, contrast arthrography, linear tomography, ultrasound, computed tomography, scintigraphy and magnetic resonance. Survey radiography is the first choice imaging modality for diagnosing osteochondrosis dissecans in dogs. In cases where survey radiography fail to demonstrate a lesion other modalities such as scintigraphy, linear tomography, computed tomography, and magnetic resonance may be helpful. Survey radiography, contrast arthrography, computed tomography, and magnetic resonance may also provide additional information contributing to early diagnosis and treatment.

Fragmented medial coronoid process of the ulna in the dog

Fragmented medial coronoid process of the ulna is an important cause of elbow dysplasia in the dog. Etiologic factors that have been identified include osteochondrosis, ulnar trochlear notch incongruity or dysplasia, and asynchronous growth of the radius and ulna. Treatment options that are discussed are conservative medical management, surgical removal of the coronoid fragments, and ulnar osteotomy or ostectomy. Prognosis is variable and depends on etiologic factors and response to therapy.

Diagnostic and surgical arthroscopy in osteochondrosis lesions

In the dog, as in man and the horse, arthroscopy has an important role in treatment of joint disease. In the shoulder, elbow, and stifle joints, surgical arthroscopy can and should replace the classical surgical methods of treating osteochondrosis lesions. In elbow and tarsocrural joint disorders, the diagnostic potentials of arthroscopy are evident. With the established techniques, not only can the lesions be diagnosed with accuracy, but they can also be treated within the same procedure, making arthroscopy the treatment of choice to deal with osteochondrosis lesions. Without a doubt, arthroscopy will play an important role in the understanding of the etiopathology of different joint diseases, especially within the elbow joint, where so many questions remain unresolved. The advantages of arthroscopy in the diagnosis and treatment of osteochondrosis have also encouraged other veterinary surgeons to adopt the technique. In the developmental stage of arthroscopy in the dog, a frequently expressed comment was that arthrotomy was as valuable and as easy (or easier) to perform as arthroscopy. Now that the advantages of arthroscopy have been demonstrated, the skepticism has changed into enthusiasm. The same evolution is noted with arthroscopy in both man and the horse.

Diagnostic imaging of osteoarthritis

Osteoarthritis is a common orthopedic problem in the small animal patient. In most cases, the degenerative changes in the joint are secondary to some predisposing cause. The objective of diagnostic imaging is to define the extent and nature of the degenerative changes and to identify the responsible underlying abnormality. To achieve this, appropriate imaging procedures should be used. Although conventional radiography is the most common method used to evaluate osteoarthritis, there has been an increase in the application of other imaging technologies during the past several years. These modalities can provide the clinician with additional information that can improve case management. The radiographic changes that accompany osteoarthritis are reviewed, and indications for the various imaging modalities are outlined. The causes and presentation of osteoarthritis of the major diarthrodial joints of the appendicular skeleton are described.

Arthroscopic findings in 100 dogs with elbow lameness

Elbow arthroscopy was performed in 100 dogs with foreleg lameness localised to the elbow joint, bilaterally in 48 of them, making a total of 148 joints examined. Lesions in the area of the medial coronoid process varied from cartilage fissures in 13 to fragmentation in 91, chondromalacia-like lesions in 27. This last lesion has not been reported previously in the veterinary literature. Kissing lesions on the medial side of the humeral condyle were present in 83 joints, whereas lesions of osteochondritis dissecans were found in only three. All these lesions were associated with varying signs of synovitis and arthrosis. Arthroscopic signs of arthrosis and/or synovitis without associated medical coronoid lesions were found in 14 elbow joints.

Microradiography of the feline marginal periodontium with a microfocal high-resolution x-ray system

The present paper is a cross-sectional microradiographic study. Postmortem hemimandibles were radiographed with a microfocal high-resolution method. Microradiographic appearances of the feline periodontium are described and discussed. Mean relative alveolar bone support in clinically and histologically normal cats was 46.9%. Site-specific alveolar bone support (ABS) was calculated twice (blind). The 95% confidence limits of the method error for one observation were estimated. Differences between two site-specific measurements did not exceed +/- 2.72%. Microfocal radiography yielded valuable additional information about the feline periodontium and made it possible clearly to identify important dental and periodontal structures such as the CEJ (cementoenamel junction) and the bottom of infrabony defects.