Knee Injuries in Dogs Quiz

Lameness in Companion Animals

• Lameness is a disruption of normal locomotion
• Understanding how various presentations of lameness relate to different injuries is crucial
• Constructing a differential diagnosis list based on clinical presentations, selecting appropriate diagnoses, and identifying suitable medical/surgical interventions are essential
• Determining an appropriate prognosis for the common causes of lameness is also vital.

Learning Objectives

• Understand how various presentations of lameness in companion animals relate to different injuries
• Construct a differential diagnosis list based on clinical presentations related to common causes of lameness
• Determine appropriate diagnostics
• Determine appropriate medical and surgical interventions for the management and treatment of common causes of lameness
• Determine appropriate prognosis for common causes of lameness

Lameness: Disruption of Normal Locomotion

• Categories include: orthopaedic, oncological, and neurological
• Images of each category are included.

Clinical Approach

• History and signalment
• Distant observation
• Gait observation
• General physical examination
• Orthopaedic/neurological assessment
• Systemic issue or not?
• Affected limb(s)
• Affected structure(s)
• List of differential diagnosis

History

• Owner's complaint (affected limb(s), severity, onset)
• Acute or insidious onset?
• Traumatic episode associated?
• Is the lameness intermittent or continuous?
• Does the lameness improve, worsen, or remain static during the day/after rest/exercise?
• Does the severity change with the ground surface?
• Is the animal comfortable lying, sitting, and standing?
• How much exercise does the animal receive currently?
• General well-being
• Travel history/imported from abroad?

Distant Observation

• Off-loading of affected limb during standing
• Weakness
• Plantigrade stance
• Difficulty in rising/sitting
• Does the animal sit square?

Gait Analysis

• Observe animal's gait at walk and trot
• Bilateral lameness may be difficult to observe.
• Forelimb lameness: head nods downward as the sound limb is placed, head nods upward when the lame limb is placed.
• Hindlimb lameness: dorsal displacement of the pelvis, shortened stride

Lameness Grading

• Scoring system for assessing lameness
• Includes descriptions of the lameness associated with each grade
• Grade 0-5
• Scoring for lameness should use various clinical tools

Orthopaedic Examination

• Examine the lame limb last (pain elicited)
• Large/giant breed dogs are most easily examined on the floor.
• Small breed dogs/cats examined on the clinical examination table.
• Assistance may be required
• Purpose: to identify anatomical deformities/displacement, pain/crepitus, range of movement of joints, integrity of supporting structures of each joint

List of Differential Diagnosis

• Lists potential diagnoses by age group (dogs <1 vs >1 year) and breed (large vs. small vs. chondrodystrophic)
• Specific diagnoses include: cranial cruciate disease, patella luxation, panosteitis, osteosarcoma, degenerative joint disease, and avascular necrosis.

Cranial Cruciate Disease (CCLD)

• Signalment: small and large breeds, young and old, males and females, cats
• History: sudden onset of non-weight-bearing or partial weight-bearing lameness (acute CCLD), or mild weight-bearing lameness associated with exercise, improves with rest (partial tear)
• Chronic: weight bearing lameness associated with osteoarthritis

Physical Examination

• Postural changes (lameness, off-loading affected limb during stance, "sit-test")
• Palpation (effusion, pain on hyperextension, pain on flexion, loss of ROM, atrophy of muscles, medial buttress, cranial drawer/tibial compression test, meniscal click)

Cranial Drawer Test

• Patient in lateral recumbency
• Hold the patella/caudal aspect of lateral femoral condyle
• Locate tibial tuberosity/fibular head
• The tibia is moved forward/relative to the femur
• Painful-difficult to perform

Cranial Tibial Thrust

• Patient’s stifle in near full extension
• Use one hand on patellar ligament / tibial tuberosity
• Flex the hock with the other hand
• Observe for movement of the tibial crest in relation to femur

Radiology

• Osteophytes (around distal patella, supratrochlear region, tibial and femoral margins)
• Fat pad sign (area cranial to the femur whiter than normal stifle)

Treatment Options

• Conservative treatment (rest, 6-8 weeks), more effective in small dogs (<15kg) if ineffective meniscal damage
• Surgical treatment (medium/large dogs >15kg), arthrotomy/arthroscopy, tibial plateau leveling osteotomy, tibial wedge osteotomy, TTA

Patella Luxation

• Signalment: younger dogs (small breeds >> large breeds), MPL more frequent in small than large breeds, cats
• History: intermittent, weight-bearing lameness related to grade of luxations
• Leg in flexed position, few steps, skipping
• Concurrent CCLD 25%

Grading of Patella Luxation

• Grade 1, 2, 3, 4
• Clinical symptoms and deformities are considered for proper grading

Clinical Examination

• Identify the patella
• Move the stifle through its ROM
• A popping sensation when luxating is often associated with the sign

Investigations: Radiology

• Standard orthogonal radiographs of the stifle should be obtained (craniocaudal, lateral)
• Evaluate patella position
• Assess for joint effusion and degenerative changes
• Substantial changes indicate CCLD

Treatment Plan

• Conservative treatment (Grade 1 and 2): physiotherapy, hydrotherapy
• Surgical treatment (Grade 3 and 4); also Grade 2 if the dog is lame/painful

Bone Tumours in Dogs

• Signalment: middle-aged/older patients, large breeds
• History: severe lameness, poor response to analgesia, bony swelling, pathological fracture
• Most common: osteosarcoma
• Other diagnoses: chondrosarcoma, hemangiosarcoma, fibrosarcoma, secondary metastasis (urogenital, mammary)
• Common sites: 75% appendicular, forelimbs > hindlimbs

Investigations

• Imaging findings (cortical bone thinning, bone lysis, bone proliferation, elevation of periosteum mottled appearance, thoracic imaging, high metastasic rate required 3 chest views (radiography or CT))
• Tissue biopsy (Jamshidi bone biopsy needle)

Bone Neoplasia in Dogs: Treatment and Prognosis

• Tumor-specific information on incidence, metastasis, treatment, and prognosis

Bone Tumours in Cats

• Rare in comparison to dogs
• Osteosarcoma most common.
• Signalment: mature cats
• Presentation: lameness, limb deformities, pathological fractures
• Diagnosis; local radiographs and thoracic radiographs
• Treatment: amputation
• Prognosis: reasonable with amputation, 10% risk of metastasis

Panositis

• Signalment: Young dogs (<2-year-old), male > female, large breeds
• History: shifting lameness, pain on palpation, chronic intermittent lameness
• Investiation: patchy areas of increased opacity within medullary canal (thumb print sign)

Treatment and Prognosis (Panositis)

• Conservative treatment: pain relief, exercise restrictions
• Self-limiting: resolves within 2 years

Degenerative Joint Disease (DJD)

• Signalment: middle-aged/older patients, small and large breeds (cats affected as well)
• History: lameness/stiffness, chronic presentation, insidious onset, worsens morning/rest, improves with exercise/warming up
• Difficulty raising/jumping/stairs, altered behaviour(aggression, lethargy), urination and defecation outside the litter tray (cats)

Clinical Examination (DJD)

• Stiffness, lameness, muscular atrophy, reduction in ROM, crepitus, altered gait (reduce stride length, altered swing phase), unkept appearance (cat), pain on examination, swollen joints

Investigations (DJD)

• Radiography (signs nonspecific, osteophytes, enthesophytes, intra-articular mineralisation, subchondral sclerosis, soft tissue enlargement)
• Synovial fluid analysis, arthroscopy

Conservative Treatment (DJD)

• Client education, expectations, weight control(ideal body condition score), exercise control, environmental changes for cats (access to feeding bowl, favourite sleeping spot, litter box)
• Physiotherapy/Hydrotherapy
• Medical management (NSAIDs, paracetamol, gabapentin, amantadine, monoclonal antibody therapy)
• Nutritional supplementation

Avascular Necrosis of Femoral Head (Legg-Calvé-Perthes Disease)

• Signalment: small breed dogs (miniature poodles, WHWT), young 4-11 months, cats affected by similar issue
• History: variable lameness, potentially non-weight bearing
• Clinical findings: pain, crepitus on hip examination
• Investigations: radiography
• Treatment: femoral head and neck osteotomy, total hip arthroplasty