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tvpjournal.com | September/October 2016 | T O day' S Ve T erinary Prac T ice Ju V enile Or T h OP edic d i S ea S e in dO g S & c a TS Peer r eviewed 29 Treatment Treatment generally involves intense physical therapy, including splinting, bandaging (eg, hobbles), and muscle strengthening exercises. 3,7,8 With aggressive treatment and environmental changes, a response is often noticed within the first 3 to 4 weeks. 3 Extreme care must be exercised when bandages and/or splints are placed on growing animals because these devices must be changed frequently to avoid complications. Owners must also be properly educated on the care of such devices, with instructions to monitor for soiling, movement/ slipping, swelling, or exposed digits. For animals with pectus excavatum, surgical correction of the deformity is recommended, if they have respiratory compromise or severe deformity. 3,7,8 The reader is referred to the references for more specific details on the management of pectus excavatum because this is beyond the scope of this article. Prognosis Prognosis can be good for patients whose condition is detected and treated early with therapy and supportive care. For chronic or untreated cases, prognosis is guarded. Humane euthanasia is often chosen when owners are unable to meet the high demands of nursing care and physical rehabilitation exercises or when severe joint/limb rigidity has developed. 3,8 PEDIATRIC CARTILAGE DISEASES Osteochondrosis Overview Osteochondrosis (OC)—also known as osteochondritis dissecans and osteochondrosis dissecans (OCD)—is a complex, multifactorial condition. Discussion of the etiopathogenesis is beyond the scope of this article; however, the interested reader is referred to Ytrehus et al 9 for a thorough review. OC is a common disorder of developing cartilage in humans and domestic animals. The exact cause has been theorized, but one common unifying theme has not been identified. 9 It is generally accepted that the disease results from an aberration in endochondral ossification, the process whereby cartilage is gradually converted into bone. 10 Ytrehus et al 11 have proposed classifying articular OC on the basis of disease stage. In this system: • Osteochondrosis latens refers to the presence of an early, microscopic lesion • Osteochondrosis manifesta refers to subclinical lesions that are macroscopically and radiologically apparent • Osteochondrosis dissecans refers to patients in which attached or loose cartilage flaps are present, typically resulting in clinical signs (Table 4). 9,11 Lesions can occur in both the physis and epiphysis; however, for this discussion we will focus on OCD of the epiphysis (articular lesions). Signalment Animals are typically 4 to 8 months of age, with males more commonly affected than females. Large- and giant-breed dogs are most commonly affected, but the condition can occur in small breeds and cats. 12 Diagnosis Affected animals are often not clinical until a cartilage flap develops. 10 OC should be considered in any young, large-breed dog with lameness and a swollen, painful joint. 10 The contralateral joint should be evaluated regardless of clinical signs because OC is most typically bilateral. Orthogonal radiographs of the affected joint are often diagnostic. Defects in the subchondral bone, flattening of the normal contour and, in some cases, sclerotic margins are typically noted (Figures 4 to 6, page 30). Mineralization of the cartilage flap may also be noted. A positive contrast arthrogram can be helpful in identifying lesions when the cartilage flap has not mineralized. Computed tomography (CT) and MRI can be helpful in detecting early lesions and in imaging more challenging joints (eg, tarsus and elbow). 10 Finally, arthroscopy can be used for direct visualization of the lesion and, in some cases, allow treatment at the same time. Treatment Treatment options vary according to the joint affected and the lesion size. Medical management— maintaining a lean body condition, physical rehabilitation, regular controlled activity, and NSAIDs—is an option in most cases. • Shoulder OCD is very amenable to fragment removal with curettage of subchondral bone Table 4. Reported & Accepted Clinical Manifestations of Osteochondrosis Dissecans in Dogs 10 • Caudomedial aspect of the humeral head • Medial aspect of the humeral condyle • Lateral or medial femoral condyle • Medial or lateral trochlear ridge of the talus