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Diagnostic and Treatment of Joint Diseases of Small Animals

UpdatesClinical Management

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Introduction

Increase of the frequence of joint diseases in dogs and cats due to:

increase of life expectancymore medium - large breedsmore obese animalsIncrease of animal of predisposed breeds

Difficult to accurately diagnose

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Structure of Joint

Synovial fluidfeeds the cartilage

+ lubricationArticular Cartilage« shock absorption »

Subchondral plate:« support »

Joint Capsule:ligament-likestructure

+ synovialmembrane

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The Healthy Cartilage

Matrix: shock absorption80% water12% collagen2% proteoglycansother substances

Chondrocytes:synthesis of proteoglycanssecretion of catabolic enzymes

=> regulation system:balance synthesis / degradation

Sources: McIlwraith, C.W., Trotter, G.W. (1996): Joint disease in the horse., W.B. Saunders, Philadelphia, USA.

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Structure of Cartilage Matrix

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Physiology of Cartilage

Not irrigated by blood vessels=> specific nutrition system: « pumping »

DEPRESSIONaspiration of the synovial

fluid

COMPRESSIONrejection of waste in the

synovial fluid

WASTE NUTRIMENTS

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Inflammatory Joint Diseases

Very numerous:more than 300 are listed in the litterature

Varied causes:immune mediated factorsmicrobial infectionsecondary effect of trauma

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Inflammatory Joint Diseases

Immune mediated polyarthritis

Picture: Masahiro Okumura..

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Non-Inflammatory Joint Diseases

Degeneration of joint structures, like cartilage:

OSTEOARTHRITIS

OSTEOARTICULAR DYSPLASIA

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General Pathogenic Process

In case of joint disease:

Modification of cartilage matrix homeostasis

=> lowering of viscoelasticity

=> increase of frictions

This leads to degenerative disease= osteoarthritis (OA) = degenerative joint disease (DJD)

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OA Pathogenic Process: Phase 1

Over-pressureon normal cartilage:

luxationunstability of the jointdysplasiaoverweight

OR Normal pressureon un-normal cartilage

tumoral processold cartilagegenetic malformationnutritionnal troubles

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OA Pathogenic Process: Phase 2Hyperpressure

Increase ofMetalloproteases

Decreaseof synthesis

Release of cartilage fragments

PgE2

Inflammation

Activation of chondrocytes

Destructionof cartilage Matrix

PAIN

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OA Pathogenic Process: Phase 3Hyperpressure

Increase ofMetalloproteasesDecrease

of synthesis

Release of cartilage fragments

Inflammation

Activation of chondrocytesIL 1 beta

Activation of synoviocytes

Destructionof cartilage Matrix

IL 1 betaIL6TNF alpha

PgE2

Synthesisof proteases

+m

acro

phag

es

PAIN

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OA Pathogenic Process: Results

Fibrosis of the capsuleOsteophytesBone remodelling

Healthy OA

Biochemicaland MechanicalVicious Circle

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General Physical ExaminationInterview of the owner:

Sudden / slow onset of the disease ?Date of apparition and evolution, cyclic or permanent ?General mobility of the animal + specific motion of the legs ?

Demeanour

Examination of the Gait

Neurological tests (to exclude neurological etiology)

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Examination of Lameness

Focus on the attitude of the legsAnimal walking toward you / away from you

Permanent / intermitent lameness ?

Strides of each foot ?

Movements of joint under loading ?

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Orthopaedic Evaluation (1)

Animal standing still:

Posture ?Muscle atrophy ?Muscular reaction ?Pain along the spine, at the neck or the back ?

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Orthopaedic Evaluation (2)

Palpation (1):identifiate painful bones, ligaments, tendons

Abnormalities ? Displacements ?Joints with fibrosis ?Pain ?In-stability ?

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Orthopaedic Evaluation (3)

Palpation (2):

Restriction in the motion of any leg / joint ?Crepitus ?Condition of soft tissues around joint ?Swelling ?

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Orthopaedic Evaluation (4)

Palpation of the joint of the elbow

Picture: Masahiro Okumura..

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Orthopaedic Evaluation (5)

Palpation of the joint of the elbow

Picture: Masahiro Okumura..

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Orthopaedic Evaluation (6)

Palpation of the joint of the hip

Picture: Masahiro Okumura..

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Orthopaedic Evaluation (7)

Biodynamic tests:

To carry out on a sedated / anesthesied animal

To evaluate stability of the joint

Cranial drawer signOrtolani signBarden sign

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Orthopaedic Evaluation (8)

Biodynamic tests:

Cranial drawer sign

anterior cruciate ligament rupture of the knee joint

Source: Whittick, W.G. (1990): canine Orthopedics. Lea & Febiger, Philadehphia, USA.

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Orthopaedic Evaluation (9)

Biodynamic tests:

Ortolani sign

stability of hip joint having dyspasia

Source: Whittick, W.G. (1990): canine Orthopedics. Lea & Febiger, Philadehphia, USA.

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Diagnostic Imaging

Changes in joint structure

Sources: McIlwraith, C.W., Trotter, G.W. (1996): Joint disease in the horse., W.B. Saunders, Philadelphia, USA.

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Diagnostic Imaging: X-Ray

Time gap between the begining of the disease and the stage when the lesions are detectable by radiography

All lesions may not be all related to the present disease

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Diagnostic Imaging: X-RayOA of elbow joint

Fragmented medial coronoid process

Remodeling of the subchondral bone

Source: Whittick, W.G. (1990): canine Orthopedics. Lea & Febiger, Philadehphia, USA.

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Diagnostic Imaging: X-RayOA of hip joint

Source: Whittick, W.G. (1990): canine Orthopedics. Lea & Febiger, Philadehphia, USA.

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Diagnostic Imaging: X-RayOA of knee joint

Source: Whittick, W.G. (1990): canine Orthopedics. Lea & Febiger, Philadehphia, USA.

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Diagnostic Imaging: Arthroscopy

Interest:

direct observation of ligaments, tendons, synovial membrane, articular cartilage

biopsy of synovial membrane

excising, removing fragments

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Diagnostic Imaging: Arthroscopy

Arthroscopy of the Elbow

Picture: Masahiro Okumura..

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Diagnostic Imaging: Arthroscopy

Fragmented coronoid process of ulna

Erosion ofcartilage

Hyperplasiaof synovial membrane

Coronoidprocess

Fragmentedmedialsurfaceof ulna

HUMERUS

RADIUS

Sources: McIlwraith, C.W., Trotter, G.W. (1996): Joint disease in the horse., W.B. Saunders, Philadelphia, USA.

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Diagnostic Imaging: Arthroscopy

Fragmented coronoid process of ulna

=> Inflammation of thesynovial membrane

Biceps tendon inthe shoulder joint =>

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Diagnostic Imaging: Tomography

X-Ray CT:excellent for detecting calcification

X-Ray CT 3DMRI:

can show images of soft tissues like cartilage and tendon

Limits:costdeep sedation / anesthesia requiredresolution of the images obtained

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Diagnostic Imaging: Tomography

X-Ray CT:Fragmented coronoid process of ulna

Picture: Masahiro Okumura..

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Diagnostic Imaging: Tomography

X-Ray CT 3D:Fragmented coronoid process of ulna

HUMERUS

ULNA

RADIUSULNA

HUMERUS

Picture: Masahiro Okumura..

Picture: Masahiro Okumura..

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Diagnostic Imaging: Tomography

Ultrasonography:

useful in detection of lesions of biceps and ligaments

not a practical examination for joints because of a very small acoustic window in this particular area

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Tests on Synovial Fluid

Interesting to detect and evaluate:infectionsneoplasiainflammation

Puncturing:a perfect aseptia is required22-25G needle2ml syringe

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Tests on Synovial Fluid

Elements to analyse:amount of fluidappearancecytological analysis

presence of PNN => inflammationPNN morphology: immune disease vs. infection

protein contentbacteriological culture test

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Tests on Synovial Fluid

Amount of fluidAppearance

Picture: Masahiro Okumura..

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Treatment Strategy

Conservative therapyremove the cause of the diseasecontrol pain and inflammationprotect the damaged cartilage

=> a Combined Drug Therapy is needed

Surgical treatmentoften last resort

when the control of painbecomes impossible

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Conservative Therapy

Supportive treatment:

Mild exercice is needed every day:to maintain range of motion of jointto strengthen soft tissues around the jointto enhance the metabolic activity of cartilage

Weight controlto decrease the over-pressure on the cartilage

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Conservative Therapy

Purposes of drug therapy:

Control of Pain, on short and long term for animal welfare & to support cartilage physiologyControl of InflammationModify the cartilage Matrix Metabolism

Long term treatment => drugs with minimal side effects are required

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Conservative Therapy: Drugs (1)

Available drugs:NSAIDs: oral & injectableDMOAs: oral & injectable

(Disease-modifying osteoarthritis agents)

Steroids: oral & injectableMorphinics: oral & injectableLocal anesthetics

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Conservative Therapy: Drugs (2)

All drugs are complementary:

DrugsReduction of

Pain Reduction of

InflammationProtection

of cartilageAdverse effects

NSAIDs ++, short term

++, short term

0/+ +

DMOAs ++, long term

++, long term

+++ 0

Steroids ++, temporary

+++ - - - ++

Morphinics ++ 0 0 + Local

anesthetics +++,

short action0 0 0

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Conservative Therapy: Drugs (3)Hyperpressure

Increase ofMetalloproteases

Increase ofsynthesis

Release of cartilage fragments

Inflammation

Activation of chondrocytesIL 1 beta

Activation of synoviocytes

Destructionof cartilage Matrix

IL 1 betaIL6TNF alpha

PgE2

Synthesisof proteases

CS

CS

NSAID

NSAID

NSAID

NSAIDCS

CS

CS

CS

PAIN

MorphinicsLocal Anesth.

+macrophages

Steroids

Steroids

CS

CS = Chondroitin Sulfate (DMOA)

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Conservative Therapy: Drugs (4)

Drug Strategy:

Common case: NSAID (short-medium term)

+ DMOA (from the beginning- long term effect)

If severe inflammation: + Steroids (short term)

If severe pain still present after NSAIDs:+ Local anesthetics+ Morphinics

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Conservative Therapy: Drugs (5)

Available DMOAs:

Drugs Pro Cons Recommendations

Chondroitine Sulfate

- Anti-inflammatory + chondroprotective effect

- The predominant proteoglycan in the matrix

- Carry-over effect

- Needs 2 weeks to show effects by oral route

- Highly degradated in the digestive tract

- As soon as the begining of the treatment, in

combination with pain killers - Long term management

Hyaluronic acid - Lubrication role when

injected in the joint

- Difficult management of injections on the long

term

- Injection at the begining of the treatment

Glucosamine

- Lubrication role when injected in the joint

- Resistant to digestive enzymes

- More structural than anti-inflammatory effect

- No direct study in small animals

- Idem CS - May be completed with NSAIDs on the long term

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Surgical Treatment

Arthrodesiscommon procedure

Replacement arthroplastyuse of artificial materials=>use for the hip joint of large dogs only

Excisional arthroplastyEasier, but functions reduced after surgery(except for the hip)

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Surgical Treatment: Arhrodesis

Articulardisintegration

Picture: Masahiro Okumura..

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Conclusion

Joint diseases concern welfare and quality of live

Easy and objective methods for diagnosisTreat the underlying diseasesRestore joint functionCombined therapy is needed for treatment, in addition to animal welfare & quality of life