Osteochondritis Dissecans
As A Cause of Shoulder Lameness in the Big Dog
Sudden forelimb lameness in the juvenile dog of the larger breeds may be a manifestation of osteochon-dritis dissecans, an increasingly diagnosed condition of the shoulder joint.

The disease has been reported as occurring most frequently in large and giant breeds between the ages of 5 and 12 months, a time at which the skeletal system is most susceptible to injury. A typical history of lameness after strenuous exercise of sudden stops in front of fences, and hi connection with training or jumping is common.

The symptoms of lameness, refusal to use the affected limb, painful resistance to full extension of the forelimb and atrophy of the shoulder muscles are common findings. These symptoms are the result of an injury to the subchondral bone and cartilage of the shoulder joint. Pathologically, these lesions are seen as a bone necrosis of the central portion of the humeral articular surface with discoid plaques of cartilage at the site of injury.

A diagnosis of osteochondritis dissecans is most often made by the clinical symptoms of shoulder lameness after strenuous exercise. Radiographic diagnosis is helpful in severe or long standing cases, but hi the acute stage lesions may not be apparent radio-graphically.

Fortunately, most dogs afflicted will make a functional recovery with rest and restricted exercise. Some veterinarians have used intra-articular injections of steriods to shorten the recovery period. More persistent cases of the disease may require surgical intervention to remove the bony lesion or pieces of detached cartilage within the joint capsule.

Although osteochondritis dissecans is more prevalent in some breeds and in some lines than others, breeders, trainers and large dog fanciers can help prevent this condition by exercising judgment in the amount of exercise a juvenile is allowed during this critical period of his development.

Canine Elbow Dysplasia
Elbow dysplasia is a descriptive term applied to a developmental abnormality of the elbow joint that is manifested by bony changes and foreleg lameness. Elbow dysplasia has been described in the German Shepherd Dog, St. Bernards, Irish Wolfhounds, Basset Hounds, Newfoundlands, Bloodhounds, Labrador Retrievers and Great Danes. This disease has been diagnosed hi dogs ranging in age from three and a half months to three years, with six months the most frequently reported age of diagnosis. Elbow dysplasia has not been reported in the small breeds of dogs.

Clinical signs of the disease vary from slight lameness to refusal to bear weight on the affected limb. The lameness generally is gradual in appearance, intermittent in nature and may become more pronounced after exercise. A frequent complaint is lack of drive in gaiting and loss of stamina. One leg or both forelegs may be affected. Severely affected dogs stand with bowed elbows and have swollen joints with increased joint fluid. These dogs resent forced movement of the elbow joint.

The diagnosis of elbow dysplasia is based on radio-graphic findings of an ununited anconeal process (which is a loose fragment of bone in the posterior portion of the elbow joint) and/or early osteoarthritis of the elbow with the arm flexed is a diagnostic clue for the observation of the anconeal process. Care must be taken in viewing radiographs of large dogs under 140 days of age since normal bony union is not complete until after this time.

Treatment of this condition is aimed at relief of pain by surgically removing the loose bone fragment within the elbow joint before osteoarthritic changes become aggravated. Experimental trial breeding of dogs with elbow dysplasia indicate the condition to be an inherited trait with a strong familial tendency. The mode of inheritance is thought to be that of three dominant genes controlling the appearance of the disease.

Since elbow dysplasia is an inherited abnormality, affected dogs should not be considered for breeding. Dogs with elbow dysplasia should be removed from breeding programs and preferably neutered for use as pet animals. Surgical removal of the ununited anconeal process has been useful hi the relief of pain and lameness associated with the disease.