VSSF presents the following case study.

OSTEOCHONDROSIS Andrea Gale

“Buddha” 7 month MI Rottweiler Several week history of pain when rising No other health concerns ▫Owner treating yard for ticks PE ▫Abnormal findings:  Pain on flexion and extension of both elbows  R>L  Severe joint effusion bilaterally  R>L  Severe tick infestation

Differential Diagnosis Elbow Dysplasia ▫Un-united Anconeal Process ▫Osteochondrosis Dessicans ▫Fragmented Coronoid Process ▫Elbow Incongruity  Malalignment and malformation of joint  Un-united medial epicondyle Trauma Septic arthritis Panosteitis Hypertrophic Osteodystrophy

Diagnostics Radiographs ▫Mild periosteal reaction of the horizontal portion of the anconeal process in the R elbow. ▫Focal subchondral bone defects in the medial humeral condyle of both humeri. Diagnosis : Osteochondritis dissecans of the L and R distal humeri. DJD of the right elbow

Diagnosis: OCD and DJD

Treatment Medical Management ▫Deramaxx 75mg: ½ t PO SID ▫Tramadol 50mg: 1 ½ t PO BID ▫Frontline Spray: 1 spray/lb ▫Preventic Collar Advised strict exercise restriction and short leash walks only until surgery

SurgicalTreatment Bilateral Elbow Arthroscopy ▫Large, osseous chondral fragments off the medial coronoid process with some fibrous attachment ▫fragmented medial coronoid processes bilaterally

Post Op & Follow Up Light pressure bandage placed Oral Antibiotics ▫Simplicef 100mg – 1t PO SID NSAID ▫Deramaxx 75mg – 1/2t PO SID Tramadol 50mg – 1 1/2t PO B- TID Exercise Restriction 6 weeks Post Op ▫Doing well ▫Still weak at arising ▫Restricted to leash walks  30min x2 per day

DEVELOPMENTAL ORTHOPEDIC DISEASES Common cause of lameness and pain in young dogs ▫Dx – challenging  Signalment  History  PE – orthopaedic and neurologic  Radiology +/- MRI, CT or nuclear scintigraphy DIFFERENTIAL DIAGNOSIS: THORACIC LIMB ▫Osteochondritis dissecans ▫Ununited anconeal process ▫Fragmented coronoid process ▫Elbow incongruity ▫Angular limb deformity ▫Panosteitis ▫Hypertrophic osteodystrophy ▫Retained cartilaginous core ▫Traumatic injuries  fracture, luxation, subluxation, avulsion, strain/sprain

OCD of Humeral Condyle DEFINITIONS OSTEOCHONDROSIS ▫AN ABNORMALITY OF ENDOCHONDRAL OSSIFICATION OSTEOCHONDROSIS DISSECANS ▫Implies actual separation between this region of thickened cartilage and the underlying bone  Convex surfaces  Most commonly – shoulder, elbow, stifle and hock joint

Normal Epiphyseal Devlopment Epiphyseal growth centre – secondary Ring of productive chondrocytes form on the periphery Chondrocytes facing the articular surface form articular cartilage ▫Superficial region ▫Deeper portion ▫Requires vascularization for calcification

PATHOPHYSIOLOGY The mechanism of OCD ▫Primary disturbance or failure of endochondral ossification  increased articular cartilage thickness A) Cartilage Nutrition Theory ▫Increased thickness of cartilage impedes diffusion of nutrients from synovial fluid  Basal layers cartilage degenerate necroses B) Focal Compression Theory ▫Increased pressure prevents /decreases perfusion and vascular invasion ▫Lack of vascular supply and failure of cartilage transformation

GROSS PATHOLOGY Primary gross lesion is a dissecting intracartilaginous separation b/w the calcified and non calcified layers Four grades ▫1)Grossly normal articular surface with a small subchondral bone defect ▫IV) vertical fracture of the articular cartilage and separation of the resulting flap from the underlying bone

ETIOLOGY Diet and growth rate ▫Increased energy intake, growth rates and birth weights *** Hormonal balance Trauma ▫Intense exercise; ischemia Joint morphometry Genetics ▫High incidence of FMCP and OCD occurring simultaneously ▫Multifactorial heritability ▫Difference in sex incidence ▫Dominant, recessive or x- linked gene  Consider sterilization

SIGNALMENT Highest in Newfoundlands, Labrador retrievers and golden retrievers ▫Other breeds: Bernese Mountain dog, Chow chow, GSD, mastiff, old English sheepdog, Rottweiler, and standard poodle OCD/FMCP = higher in males Age of Onset: 4 to 7 months Age of Diagnosis: 6 to 18 months

HISTORY Mild to severe weight bearing lameness of variable duration Recumbency, reluctant to stand or move if severe bilateral disease Generalized muscle atrophy of the affected forelimbs Swelling of the elbow joint

CLINICAL FINDINGS Orthopaedic examination ▫Affected elbow slightly adducted ▫Decreased ROM  Flexion  Crepitation ▫Joint Pain & Effusion ▫Varying degrees of lameness

RADIOGRAPHY Craniocaudal and both standard and flexed mediolateral views Both elbows Medial aspect of the humeral trochlea ▫Most evident on craniocaudal view Other radiographic changes include ▫Sclerosis ▫Osteophytosis

TREATMENT OPTIONS Medical ▫Weight restriction ▫Exercise control ▫Analgesic therapy ▫Chondroprotective Agents  Glucosamine chondroitin manganese ascorbate  Cosequin

SURGICAL MANAGEMENT SURGERYARTHROSCOPIC Remove the cartilaginous flap Debride underlying subchondral bone Several surgical techniques exist ▫Medial approach and arthrotomy Becoming more popular Allow exploration of the entire joint Removal of the cartilage flap Microfracture or abrasion with curette or burr ++ limited invasiveness and improved visibility provided by magnification, arthroscopic treatment is preferred

POST OPERATIVE CARE Limb should be placed in a light pressure bandage for hours Confined to leash walking for 4 to 6 weeks Gradual return to full activity Physical therapy is recommended during the recovery phase

PROGNOSIS GUARDED ▫Surgical or medical treatment Progression of secondary DJD Early surgical treatment decreases lameness but may not prevent progression of OA

SUMMARY Abnormal endochondral ossification Common lameness in immature dogs PE and radiographs to diagnosis Treatment –surgical intervention P/O medical management for OA

QUESTIONS?? References Anderson, Mark A. Oral Chondroprotective Agents. Part I. Compendium (7). Beale, Brian S. Small Animal Arthroscopy. Saunders, Daniel, Gregory. Overview of Skeletal and Joint Lesions Seen during Canine Growth. Western Veterinary Conference, Fossum, Theresa. Small Animal Surgery. 3 rd Ed. Mosby, Slatter, Douglas. Textbook of Small Animal Surgery. 3 rd Ed. Saunders, Thrall, Donald E. Textbook of Veterinary Diagnostic Radiology. 5 th Ed. Saunders, 2007 Trostel, C. et al. Canine Lameness Caused by Developmental Orthopedic Diseases: Osteochondrosis. Compendium, Vol 24 (11):

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