Small Animal Orthopedic Disease

SMALL ANIMAL ORTHOPEDIC DISEASE

Tyler Fields, DVM

TOPICS

  • Hip Dysplasia

  • Legg-Calve-Perthes Disease

  • Hypertrophic Osteodystrophy

  • Osteochondrosis Dissecans

  • Cranial Cruciate Ligament Tears

  • Osteosarcoma

HIP DYSPLASIA

  • Definition: A congenital disease involving abnormal growth and development of the hip joint.

  • Common in large and giant breeds.

  • Characteristics:

    • The acetabulum of the pelvis is shallow.

    • The head of the femur is not held tightly in place.

  • Implications:

    • Predisposes to hip luxation.

    • Increases the likelihood of earlier onset of arthritis.

HIP DYSPLASIA (continued)

  • Clinical Presentation:

    • Some patients may present with complaints of discomfort.

    • Others may present later in life when hip instability leads to osteoarthritis.

    • Severity of disease varies; size of the patient affects presentation and manifestation.

    • Signs may include:

    • Decreased activity

    • Difficulty rising/sitting

    • Hip swaying and bunny hopping.

DIAGNOSING HIP DYSPLASIA

  • Methods of diagnosis include:

    • Gait examinations to observe movement abnormalities.

    • Radiographs to reveal:

    • Shortened femoral neck

    • Irregular/non-rounded femoral head

    • Shallow acetabulum

    • Ortolani Test:

    • A test designed to attempt to subluxate the hip joint.

    • A positive result is characterized by a "clunk" sound as the femoral head falls back into the acetabulum.

HIP DYSPLASIA GAIT

  • Gait analysis is a crucial part of the diagnostic process for hip dysplasia.

HIP DYSPLASIA INTERVENTIONS

  • Management strategies include:

    • Appropriate nutrition and feeding regimen; studies show optimal nutritional requirements are lower than for small breeds.

    • Maintaining a lean body weight.

    • Consideration of timing for ovariohysterectomy (OHE) and orchiectomy (OE).

    • Joint supplements to support joint health.

    • Surgical intervention in severe cases.

    • Long-term interventions are focused on arthritis management.

SURGICAL INTERVENTION

  • Types of surgical intervention:

    • Femoral Head/Neck Ostectomy:

    • Recommended for severe cases.

    • Juvenile Pubic Symphysiodesis:

    • Performed in puppies less than 5 months old; prematurely seals the pubic symphysis.

    • Total Hip Replacement:

    • Indicated in severe cases or when degenerative changes have established.

LEGG-CALVE-PERTHES DISEASE

  • Also known as: Avascular necrosis of the femoral head and neck.

  • Cause: Disruption of blood supply to the femoral head and neck, usually due to trauma but suspected to have a genetic component.

  • Most commonly seen in small breed dogs.

LEGG-CALVE-PERTHES DISEASE (continued)

  • Diagnostic Radiographs:

    • Show necrotic/destructive changes to the femoral head.

  • Clinical signs:

    • Joint pain and lameness associated with bone and cartilage deterioration.

  • Surgical intervention:

    • Femoral head and neck ostectomy is inevitable.

FEMORAL HEAD AND NECK OSTECTOMY

  • Procedure involves removal of the femoral head and neck (the "ball" of the ball-and-socket joint).

  • Outcome: Creates a false joint.

  • Important to manage pain both preoperatively and postoperatively.

HYPERTROPHIC OSTEODYSTROPHY

  • Definition: An auto-inflammatory disease typically seen in puppies usually between 7 weeks to 8 months of age.

  • Pathophysiology: Decreased blood flow to bone parts adjacent to the joint.

  • Commonly affects long bones of the limbs.

  • Often involves multiple limbs, with relapses lasting up to 20 months.

  • More prevalent in large and giant breeds.

HYPERTROPHIC OSTEODYSTROPHY (continued)

  • Clinical signs:

    • Symptoms vary from mild limping to severe cases with fever (up to 106°F) and anorexia.

    • Involves swollen, warm, painful bones and unwillingness to stand.

  • Treatment:

    • Suppressing the inflammatory response with NSAIDs or steroids for up to one year.

    • Additional analgesics may be needed.

    • Some cases resolve without intervention.

OSTEOCHONDROSIS DISSECANS

  • Definition: Development of a cartilage flap over bone joint cartilage leading to inflammatory response.

  • Commonly affected joints:

    • Shoulder joint (most common)

    • Elbows, knees, and ankles

  • Typically seen in fast-growing large breed dogs; more common in males than females.

OSTEOCHONDROSIS DISSECANS (continued)

  • Clinical presentation:

    • May present soreness after heavy activity; can progress to limping/lameness.

  • Diagnostic radiographs:

    • Reveal defects.

    • If the flap completely tears and mineralizes, known as a "joint mouse."

  • Treatment options:

    • Activity restriction and pain management.

    • Surgery for cartilage removal and/or plugging may be required.

    • Expected recovery time is 2-3 months.

CRANIAL CRUCIATE LIGAMENT RUPTURE

  • Description: CCL rupture is synonymous with ACL injuries in humans and is the most common knee injury in dogs.

  • Function of the CCL:

    • Prevents cranial displacement of the tibia.

    • Prevents hyperextension.

    • Prevents internal rotation.

  • Injury implications:

    • Usually associated with strenuous activity, leading to instability, inflammation, and discomfort.

    • Clinical sign includes acute lameness, often characterized by a "drawer sign."

    • Tests for diagnosis:

    • Cranial drawer test

    • Tibial thrust test

  • Risk Factor:

    • Increased risk of tearing the opposing CCL within one year of the initial injury.

CRANIAL DRAWER AND TIBIAL THRUST TESTS

  • Cranial Drawer Test:

    • Technique: Place one hand with the index finger on the stifle to stabilize and the thumb on the fabella; the other hand's index finger is placed on the tibial tuberosity with the thumb on the fibular head.

  • Tibial Thrust Test:

    • Technique: Stabilize the femur with the index finger over the patellar ligament and the tibial tuberosity; flex the hock and check for cranial movement of the tibia.

SURGICAL INTERVENTION FOR CCL TEARS

  • Types of surgical intervention:

    • Extracapsular: Surgery occurring outside the joint capsule; suitable for small dogs.

    • Lateral Stabilization: Heavy nylon or wire suture placed to function as a false ligament.

    • Intracapsular: Surgery occurring within the joint capsule.

    • Tibial Plateau Leveling Osteotomy: A technique to normalize the mechanics of the stifle joint.

    • Tibial Tuberosity Advancement: Technique to improve stability.

  • Note: Arthritis remains a risk even after surgical interventions.

  • Importance of pain management and a gradual return to physical activity post-surgery.

OSTEOSARCOMA

  • Definition: The most common bone tumor in dogs, significant in young (usually large to giant breeds) and older dogs.

  • Tumor Characteristics:

    • Dogs predominantly have appendicular tumors.

    • Common sites include the carpus, shoulder, and stifle – "away from the elbow and near the knee."

    • In cats, tumors are more likely to be axillary.

OSTEOSARCOMA TREATMENT

  • Diagnosis made with radiographs revealing bone lysis/destruction.

  • Concurrent chest films are necessary to assess for metastatic tumors.

  • Recommended treatment:

    • Amputation of the affected limb followed by chemotherapy, which improves survival rates.

    • Life expectancy of ~6-12 months with amputation and chemotherapy.

    • Amputation without chemotherapy results in a life expectancy of 3-5 months.

    • Without surgery and chemotherapy, euthanasia usually occurs 1-2 months post-diagnosis due to pain and risk of pathologic fractures.

  • Limb-sparing procedures are also available, using a bone graft to remove just the tumor.

QUESTIONS?

  • Contact: @REMDAWG THE TRIPAWD