WHAT IS ELBOW DYSPLASIA?
The term elbow dysplasia refers to a developmental and degenerative disease of the elbow joint. Essentially it is a poor fit of the three bones that must lock together to create the hinged elbow. Elbow dysplasia occurs primarily in medium to large breed dogs. Dogs with elbow dysplasia typically show signs of lameness before reaching one year of age, although in some cases lameness may not become apparent until middle age. The treatment for this disease can involve surgical and/or medical options. Several breeds are predisposed to elbow dysplasia including the Bernese Mountain Dog, German Shepherd, Rottweiler, Golden Retriever, and Labrador Retriever although other breeds can be affected. Commonly both elbows are affected.
Forelimb lameness is a relatively common presentation for the growing puppy. The developmental growth of the canine forelimb coupled with the potential for trauma in the active playful puppy predisposes for the developmental anomalies that lead to elbow dysplasia. Since considerable joint degeneration can occur over minimal time, it is critical to be aware of the predispositions to and early symptoms of all forms of this disease.
The canine elbow joint allows flexion and extension as well as a limited degree of external (pronation) and internal (supination) rotation. Elbow dysplasia can therefore lead to abnormal joint loading and mechanics and result in several related conditions developing within the joint including ununited anconeal process (UAP), osteochondritis of the medial condyle of the humerus (OCD), and fragmentation of the medial coronoid process (FCP), joint incongruence and osteoarthritis (OA). These conditions may occur independently or concurrently in the same animal. Each of these conditions may then precipitate the secondary changes associated with degenerative joint disease. The time of occurrence of UAP, OCD, and FCP is usually between the ages of four and six months. At that time, the bones and joints are incompletely formed.
The primary source of pain in elbow dysplasia is from the increased joint pressure, joint effusion, and loose cartilage fragments. In advanced cases, erosion of the cartilage is so severe that the underlying bone becomes exposed and eroded. Chronicity causes capsular scarring and eventually a decreased range of motion in the joint with resultant gait changes. The onset of gradual and variable clinical signs makes elbow dysplasia difficult to diagnose at an early stage in all cases.
A combination of physical examination, gait analysis, palpation, radiography, CT scan, or arthroscopy may be needed to adequately diagnose the syndrome. The most common symptoms associated with elbow dysplasia include limping or short striding steps in the forelimbs, difficulty lying down or rising, lying down with elbows abducted, warming out of lameness after minimal exercise, increased lameness after heavy exercise, and frequent shifting of weight with a noticeable head bob during ambulation. Manipulation of the affected joint will result in pain, potentially a grating sensation and sound (crepitus), and swelling of the joint due to excess joint fluid. Your pet may also hold the affected limb away from its body when standing or walking, and the elbow usually has a decreased range of motion. While a number of therapeutic options may allow for a reasonable return to function, it is important to determine the presence of elbow dysplasia early in the disease process and before the joint deteriorates beyond repair in order to provide the best chance of a reasonable long term outcome.
The most common surgical intervention for elbow dysplasia involves arthroscopy, which is minimally invasive surgery. Ununited anconeal process, fragmented coronoid process, and osteochondritis can often respond favourably to medical and surgical intervention if this is initiated early in the course of the disease and prior to severe degenerative changes.