Canine Hip Dysplasia

By Robert Gracia

Canine Hip Dysplasia

According to the authors of Small Animal Orthopedics and Fracture Repair, “Hip dysplasia is an abnormal development or growth of the hip joint, usually occurring bilaterally. It is manifested by varying degrees of laxity of surrounding soft tissues, instability, malformation of the femoral head and acetabulum, and osteoarthrosis.”

Definition

• Mostly confined to large working and sporting breeds.

• Can have a relative incidence of up to 47% in Saint Bernards

• Rare, but can occur in small dogs weighing under 12 kg usually caused by trauma.

Incidence

• Polygenic predisposition to congenital subluxation of the hip.

• Environmental factors such as nutrition and growth rate as puppies also contribute to disease.

• Muscle growth fails to keep up with skeletal growth, causes joint laxity.

Pathogenesis

• Failure of congruity of articular surfaces between femoral head and acetabulum leads to bony changes.

• Increased weight on adult dog with hip dysplasia will worsen condition.

• Decreased muscle mass.• Occurrence can be reduced but not

eliminated.

Pathogenesis Continued

• Young Dogs (4 – 12 mo)• Sudden onset.• Unilateral or bilateral

disease.• Soreness and pain in

hind limbs.

Clinical Signs

• Unwilling to remain active.• Decreased musculature of thigh and

pelvic region.• Choppy gait and bunny hopping.• Microfractures of the acetabular rim• Tension and tearing of nerves of

periosteum.• Positive Ortolani sign (reduction

angle) > 30 degrees.

Young Dog Clinical Signs

Ortolani Sign < 20 degrees

• Chronic Degenerative Joint Disease.

• Slowly developing lameness.

• Lameness after increased activity.

• Loss of thigh and pelvic musculature.

• Slow to rise.

Adult Dog > 15 mo

• Crepitus, restricted range of motion.

• Spinal problems, degenerative myelopathy.

• Shoulder muscle hypertrophy.• Prefers sitting over standing.• Stifle problems, cruciate rupture.

Adult Dog Clinical Signs

Radiographic Diagnosis

Normal Hips

• 50 % or greater of femoral head should be covered by the acetabular rim.

Normal Hips Continued

Abnormal Hip

• Loss of normal demarcation of acetabular rim due to osteophyte formation.

• Subluxation.• Flattening of the acetabulum and

loss of concavity.• Morgan’s Line (osteophyte

formation along the femoral neck).

Roentgen Signs

• 2 years of age for official results.• 7 grade qualitative assesment.1. “Excellent: Nearly perfect conformation.”2. “Good: Normal conformation for age and breed.”3. “Fair: Less than ideal but within normal radiographic limits.”

Orthopedic Foundation for Animals OFA

4. “Borderline: A category in which minor hip abnormalities often cannot be clearly assessed because of poor positioning during radiographic procedures. It is recommended that another radiograph be repeated in 6 to 8 months.”

OFA Continued

1. “Mild: Minimal deviation from normal with only slight flattening of the femoral head and minor subluxation.”2. “Moderate: Obvious deviation from normal with evidence of a shallow acetabulum, flattened femoral head, poor joint congruency, and in some cases, subluxation with marked changes of the femoral head and neck.”3. “Severe: Complete dislocation of the hip and severe flattening of the acetabulum and femoral head.”

OFA Hip Dysplasia

OFA 1

OFA 2

OFA 3

• The University of Pennsylvania Hip Improvement Program.

• Uses three views.• Uses a Distraction Index, which

measures passive hip joint laxity.• Radiographs taken with coxofemoral

joint under stress to evaluate laxity.• Range from 0 to 1 where 0.4 is cut

off.

Penn HIP

Distraction Index

Extended Leg VD

Distraction View

Compression View

• Measures hip joint laxity.• Angle between the center of the

femoral head and the craniolateral aspect of the dorsal acetabular rim.• Angles of greater than 105

degrees considered normal.

Norberg Angle

Norberg Angle continued

“Frog View” Dorsal Acetabular Rim View

Other Views

Treatment of CHD

• Weight Control• Physical Therapy (PROM,

massage, acupuncture, laser, thermal, electrostimulation)

Medical Management

• Supplements• Diet• Activity• Braces• Anti-Inflammatories

Medical Management Cont.

• Preventative treatment in juveniles showing no signs of osteoarthrosis.

• Juvenile pelvic symphysiodesis

• Triple pelvic osteotomy

Surgical Management

Triple Pelvic Osteotomy TPO

• Total hip replacement (curative)• Hip capsular denervation

(alleviate pain sensation, palliative)• Femoral head and neck

ostectomy (remove pain sensation by eliminating articulation, palliative)

Other Surgical Approaches

Total Hip Replacement THR

Femoral Head and Neck Ostectomy FHNO

• All pictures from Atlantic Veterinary College Lectures, (Dr. Beraud and Dr. Matthews), AVC teaching hospital, and Handbook of Small Animal Radiology and Ultrasound.

• AVC Lectures.• Dennis, Kirberger, Barr and Wrigley.

Handbook of Small Animal Radiology and Ultrasound 2nd Edition. Elsevier Limited 2010

• Brinker, Piermattei, and Flo. Handbook of Small Animal Orthopedics and Fracture 4th Edition. Elsevier Inc. 2006

Resources

Questions