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Canine Hip and Elbow Dysplasia

From the Veterinary Merck Manual Site:

Hip Dysplasia in Small Animals

By Joseph Harari, MS, DVM, DACVS, Veterinary Surgeon, Veterinary Surgical Specialists, Spokane, WA

Hip dysplasia is a multifactorial abnormal development of the coxofemoral joint in dogs that is characterized by joint laxity and subsequent degenerative joint disease. It is most common in large breeds. Excessive growth, exercise, nutrition, and hereditary factors affect the occurrence of hip dysplasia. The pathophysiologic basis for hip dysplasia is a disparity between hip joint muscle mass and rapid bone development. As a result, coxofemoral joint laxity or instability develops and subsequently leads to degenerative joint changes, eg, acetabular bone sclerosis, osteophytosis, thickened femoral neck, joint capsule fibrosis, and subluxation or luxation of the femoral head.

Clinical signs are variable and do not always correlate with radiographic abnormalities. Lameness may be mild, moderate, or severe and is pronounced after exercise. A “bunny-hopping” gait is sometimes evident. Joint laxity (Ortolani sign), reduced range of motion, and crepitation and pain during full extension and flexion may be present. Radiography is useful in delineating the degree of arthritis and planning of medical and surgical treatments. Standard ventrodorsal views of sedated or anesthetized animals can be graded by the Orthopedic Foundation for Animals, or stress radiographs performed and joint laxity measured (Penn Hip). A dorsal acetabular rim view is used by some surgeons to evaluate the acetabulum before reconstructive surgery. Modified ventrodorsal and dorsoventral projections have also been proposed in an effort to mimic the normal standing posture of dogs. Recent reviews of American and international radiographic screening programs have failed to identify a "gold standard." An evaluation shift toward genome screening may yield more promising results in the future.

Treatments are both medical and surgical. Mild cases or nonsurgical candidates (because of health or owner constraints) may benefit from weight reduction, restriction of exercise on hard surfaces, controlled physical therapy to strengthen and maintain muscle tone, anti-inflammatory drugs (eg, aspirin, corticosteroids, NSAIDs), and possibly joint fluid modifiers. Surgical treatments include pectineal myotenectomy to reduce pain, triple pelvic osteotomy to prevent subluxation, pubic fusion to prevent subluxation, joint capsule denervation to reduce pain, dorsal acetabulum reinforcement to reduce subluxation, femoral head and neck resection to reduce arthritis, and total hip replacement for optimal restoration of joint and limb functions. Additionally, femoral corrective osteotomies can be performed to reduce femoral head subluxation, although degenerative arthritis may persist.

Prognosis is highly variable and depends on the overall health and environment of the animal. In general, if surgery is indicated and performed correctly, it is beneficial. Animals on which surgery is not performed may require a change in lifestyle to live comfortably.

Elbow Dysplasia in Small Animals

(Ununited anconeal process, Fragmented medial coronoid process, Osteochondrosis of the humeral condyle)

By Joseph Harari, MS, DVM, DACVS, Veterinary Surgeon, Veterinary Surgical Specialists, Spokane, WA

Elbow dysplasia is a generalized incongruency of the elbow joint in young, large, rapidly growing dogs that is related to abnormal bone growth, joint stresses, or cartilage development. One or more of the following lesions may be present in the joint: an ununited anconeal process of the ulna, fragmentation of the medial coronoid process of the ulna, and osteochondrosis of the medial aspect of the humeral condyle. Radiographic grading of dysplastic elbow joints is performed by the Orthopedic Foundation for Animals in the USA and in Scandinavian and European kennel clubs.

Ununited Anconeal Process (UAP):

This results when there is separation of the ossification center of the anconeal process from the proximal ulnar metaphysis. Fusion should be completed by 5–6 mo of age. The fracture is postulated to result from a biomechanical imbalance of force and movement in the rapidly growing elbow. Initially, the anconeal process is connected to the ulna by a bridge of fibrous tissue, which fragments to form a pseudoarthrosis, and the elbow becomes unstable. This joint laxity continues to damage the articular cartilage, and secondary osteoarthritis results. A hereditary basis has been implicated.

Lameness develops insidiously between 4 and 8 mo of age; however, some bilateral cases may not be diagnosed until dogs are >1 yr old. Affected elbows may deviate laterally, and the range of motion is restricted. Advanced cases have osteoarthritis, joint effusion, and crepitus. Clinical signs are suggestive, and the diagnosis is confirmed by radiography. A lateral radiograph of the elbow in the flexed position allows visualization of the ununited process. Both elbows should be examined because the condition can be bilateral.


Osteochondrosis of the Medial Humeral Condyle:

This results from a disturbed endochondral fusion of the epiphysis of the medial epicondyle with the distal end of the humerus. The exact cause is unknown, but because the carpal and digital flexors originate from the ventral aspect of this structure, it may represent an epiphyseal avulsion. It results in pain on flexion of the elbow or deep digital palpation and is accompanied by soft-tissue swelling. Radiographically, radiodense structures have been seen caudal and distal to the area of the medial epicondyle.













Fragmentation of the Medial Coronoid Process:

In this condition of the medial compartment of the canine elbow, the coronoid process fails to unite, either partially or totally, with the ulnar diaphysis and, thus, does not become a part of the articular surface of the trochlear notch. Joint laxity, irritation, and finally osteoarthritis result. This condition and osteochondrosis of the medial humeral condyle are considered to be the most common causes of osteoarthritis of the canine elbow. Bone fragments can be seen by radiography, arthroscopy, or CT.














Early surgical treatment is recommended before degenerative joint disease develops. For fragmentation of the medial coronoid process, a medial arthrotomy or arthroscopy is performed and the fragmented process removed. For ununited anconeal process, either a lateral arthrotomy is performed and the ununited process removed, or a midshaft ulnar osteotomy is performed to relieve asynchronous growth and result in union of the process. Reattachment of the process by screw fixation is also an option. For osteochondrosis, the subchondral bone lesion is curetted to stimulate fibrocartilage formation. Prognosis after surgery is good if degenerative joint disease has not developed in the joint. NSAIDs (eg, carprofen, deracoxib, firocoxib, etodolac, meloxicam, tepoxalin) can be used to reduce pain and inflammation. Joint-fluid modifiers (glycosaminoglycans, hyaluronic aid)  or regular life long injections of Adequan may be useful.

Other links
An excellent over view of what hip dysplasia is and what it means for the outcome of dogs who have it.


Blue arrow illustrates elbow incongruity at the humeral-ulnar joint.

The pink arrow depicts UAP

Arrow shows fragmented medial coronoid process

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