Common names or abbreviations:
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Premature closure of the distal ulnar physis |
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premature closure of the ulna |
Description or definition:
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A dog’s forelimb from the elbow to the wrist is comprised of two bones called the radius and the ulna. Distal is a directional term used to mean the farthest from the body. The physis is an area of cartilage and bone cell production (a growth plate). If the ulnar growth plate closes too soon the ulna will not grow to its proper length. The radius, however, will continue to grow. This uneven growth can force the radius to “bow.” The condition is sometimes referred to as radius curvus or angular limb deformity. Even in less severe forms of the condition where deformity of the forelimb is not apparent, failure of the radius and the ulna to grow at the same rate produces joint incongruity in the elbows, which can lead to elbow dysplasia. For futher information see the separate GTF listing for elbow dysplasia. Premature closure of the ulna can be the result of an injury to the lower growth plate of the ulna. However, in large breed dogs the condition can also be caused by abnormal cartilage turnover. This results in retained cartilage in the distal ulnar physis that can be seen radiographically (with an x-ray). The condition may be associated with osteochondrosis and may appear in conjunction with osteochondritis dessicans. For further information see the separate entry for osteochondrosis in the GTF library. In addition to injury, over-nutrition (excess calcium, calories, supplementation or a puppy that is overweight) is speculated to play a role in onset and progression of the disease in dogs that are genetically predisposed to the condition. |
Symptoms:
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In some cases, the abnormal curvature of the forelimb may be visible to the naked eye. In other cases the growth disparity between the radius and the ulna does not result in visible deformity. Many dogs with this condition bear weight on the affected limb but experience intermittent lameness. The lameness can be caused by the rotation of the limb which forces the dog to walk on the sides of its foot. Sometimes, because this area is not padded, ulcers form on the sides of the paw. Lameness and pain can also be caused by elbow subluxation (joint looseness) or the onset of arthritis. In severe cases the forelimb may actually become flaccid due to lack of stability at the elbow. |
Diagnosis:
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A definitive diagnosis of premature closure of the ulna, radius curvus, or angular limb deformity, requires X-ray, CAT scan, or MRI. |
Treatment:
Treatment of this condition often involves surgery. If the condition has been diagnosed when the puppy is young and still possesses a significant amount of growth potential, a surgical technique is used that relieves the restraining effect of the ulna and allows continued growth of the radius. This procedure allows the growing limb to elongate in an almost normal manner. In dogs that are more mature, there are other forms of surgery that can be done to correct bone length and curvature and restore congruency to the elbow. If the condition is discovered before degenerative changes in the joints are observed, a corrective osteotomy (cutting the bones and straightening them) is sometimes done to provide the dog with better joint function and decrease the likelihood of degeneration of the wrist and elbow joints. However, post-operative surgical care and recovery is difficult and lengthy for both the dog and owner. If the condition has progressed to the point of elbow subluxation (joint looseness) or luxation (looseness to the point of dislocation), reconstructive surgery may not be effective in managing this condition.
For more information about this condition, or if your dog is experiencing lameness, consult your veterinarian for advice.
Links to sites about this disease:
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http://www.ivis.org/special_books/ortho/chapter_41/41mast.asp |
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This summary provided by:
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Jessica in Arizona |