Physeal Dysplasia with Slipped Capital Femoral Epiphysis in Cats

James Montgomery, DVMSeptember 22, 2008

Trauma is the most common cause• Most frequently in cats between 4 and 11

months• Highest incidence in cats 6 to 9 months

Treatment• Conservative• Surgical

Femoral head excision Surgical reduction and stabilization with multiple

pins Physis typically closes between 30 and

40 weeks of age in cats

No history of trauma Common presenting complaints

• Lameness• Weakness• Decreased ability to jump

Common physical exam findings• Pain• Crepitus during flexion and extension of the

hip• Muscle atrophy (less common)

Diagnosis may be challenging • Acute fractures• Minimal displacement• Chronic fractures with substantial

metaphyseal osteolysis and sclerosis• Serial radiographs may be required• In children, ultrasonography can be used to

diagnose acute slippage of the capital femoral epiphysis

Open leg lateral and frog leg views beneficial

More likely to be overweight, neutered males with delayed physeal closure

Radiographic abnormalities:• Salter Harris Type I• Variable degrees of

fragment displacement• Osteolysis• Sclerosis• More severe changes in

cats with more chronic fractures

Many cats are affected bilaterally (5 of 13 in Craig study) McNicholas, et al. JAVMA, 2002

Growth plate thicker than normal

Loss of characteristic zonal stratification

Chondrocytes lack normal columnar arrangement

• Grouped in clusters• Randomly interspersed within

the physis• Also a feature of normally closing

physes

Normal metaphyseal bone interspersed with fibrous tissue and necrotic tissue

• More prominent in cats with chronic fractures McNicholas, et al. JAVMA, 2002

Sex

Reproductive status

Delayed physeal closure

Abnormally high body weight

McNicholas study (JAVMA 2002):• 25 of 26 cats male• All 26 neutered

14 of 16 cats (those for which neutering age was recorded) were neutered at < 6 months of age

• All had at least 1 radiographically open physis Mean age of cats in study was 94.5 weeks

• Hypothesize hypotestosteronism leads to delayed closure of the capital physeal growth plate Increased exposure to cyclic shear forces

Craig study -13 cats (Vet Pathol 2001)• 85% male• Average age 16.3 months (range 4.5 – 24

months)• 9 of 10 cats (for which weights were

available) were overweight or obese• 23% were Siamese

Significantly greater than the percentage of Siamese in the control population (5%; 662/13,250)

Well-described entity in humans• Pathogenesis poorly understood

Primarily affects overweight adolescent boys• 13 years old on average• Male to female ratio ranges from 2:1 to 4:1

Onset is atraumatic and often insidious 21% to 80% of reported cases are

bilateral Undiagnosed cases are thought to be a

frequent cause of DJD in later life

Good correlation between human syndrome and feline syndrome

A genetic etiology is supported• Male predominance• Siamese cats (Craig)

Endocrine disorders possibly contribute• Unclear if obesity is a symptom of underlying

endocrine disorder or related to gonadectomy• Hypothyroidism and growth hormone deficiency

diagnosed most commonly in humans with SCFE

• No cats had signs of endocrine imbalance other than obesity (Craig)

Craig LE. Physeal dysplasia with slipped capital femoral epiphysis in 13 cats. Vet Pathol 2001;38:92-7.

Fischer HR, Norton J, Kobluk CN, et al. Surgical reduction and stabilization for repair of femoral capital physeal fractures in cats: 13 cases (1998-2002). J Am Vet Med Assoc 2004;224:1478-82.

McNicholas WT Jr, Wilkens BE, Blevins WE, et al. Spontaneous femoral capital physeal fractures in adult cats: 26 cases (1996-2001). J Am Vet Med Assoc 2002;221:1731-6.