Synovial fluid

Diagnostic and Treatment of Joint Diseases of Small Animals

Updates Clinical Management

1

Introduction

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

increase of life expectancy more medium - large breeds more obese animals Increase of animal of predisposed breeds

Difficult to accurately diagnose 2

Structure of Joint Subchondral plate: « support »

Synovial fluid feeds the cartilage + lubrication

Joint Capsule: ligament-like structure + synovial membrane

Articular Cartilage « shock absorption » 3

The Healthy Cartilage

Chondrocytes: synthesis of proteoglycans secretion of catabolic enzymes => regulation system: balance synthesis / degradation

Matrix: shock absorption

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

80% water 12% collagen 2% proteoglycans other substances

4

Structure of Cartilage Matrix

5

Physiology of Cartilage

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

COMPRESSION

DEPRESSION

rejection of waste in the synovial fluid

aspiration of the synovial fluid

WASTE

NUTRIMENTS

6

Inflammatory Joint Diseases Very numerous: more than 300 are listed in the litterature

Varied causes:

immune mediated factors microbial infection secondary effect of trauma 7

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

9

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) 10

OA Pathogenic Process: Phase 1 Over-pressure on normal cartilage:

luxation unstability of the joint dysplasia overweight

OR Normal pressure on un-normal cartilage

tumoral process old cartilage genetic malformation nutritionnal troubles

11

OA Pathogenic Process: Phase 2

Hyperpressure

Activation of chondrocytes

Decrease of synthesis

Increase of Metalloproteases

PgE2

Destruction

of cartilage Matrix Release of cartilage fragments

Inflammation PAIN 12

OA Pathogenic Process: Phase 3 Hyperpressure IL 1 beta

IL 1 beta IL6 TNF alpha

Activation of chondrocytes Increase of Metalloproteases

Decrease of synthesis

PgE2

Destruction of cartilage Matrix

Activation of synoviocytes

ph ag e ro

PAIN

+m ac

Inflammation

Synthesis of proteases

s

Release of cartilage fragments

13

OA Pathogenic Process: Results

Fibrosis of the capsule Osteophytes Healthy Bone remodelling

OA

Biochemical and Mechanical Vicious Circle 14

General Physical Examination

Interview 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) 15

Examination of Lameness

Focus on the attitude of the legs Animal 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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Palpation (1):

identifiate painful bones, ligaments, tendons

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

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Palpation (2):

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

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Palpation of the joint of the elbow


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Palpation of the joint of the elbow


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Palpation of the joint of the hip


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Biodynamic tests:

To carry out on a sedated / anesthesied animal

To evaluate stability of the joint

Cranial drawer sign Ortolani sign Barden sign

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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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Biodynamic tests:

Ortolani sign

stability of hip joint having dyspasia


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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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OA of elbow joint

Fragmented medial coronoid process


Remodeling of the subchondral bone

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OA of hip joint


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OA of knee joint

Source: Whittick, W.G. (1990): canine Orthopedics. 30 Lea & Febiger, Philadehphia, USA.

Diagnostic Imaging: Arthroscopy

Interest:

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

biopsy of synovial membrane

excising, removing fragments

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Arthroscopy of the Elbow


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Fragmented coronoid process of ulna HUMERUS

Fragmented medial surface of ulna Coronoid process Sources: McIlwraith, C.W., Trotter, G.W. (1996): Joint disease in the horse., W.B. Saunders, Philadelphia, USA.

Erosion of cartilage

RADIUS

Hyperplasia of synovial membrane 33


Fragmented coronoid process of ulna => Inflammation of the synovial membrane

Biceps tendon in the shoulder joint =>

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Diagnostic Imaging: Tomography

X-Ray CT:

X-Ray CT 3D MRI:

excellent for detecting calcification

can show images of soft tissues like cartilage and tendon

Limits:

cost deep sedation / anesthesia required resolution of the images obtained

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X-Ray CT: Fragmented coronoid process of ulna


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

HUMERUS HUMERUS

ULNA

RADIUS Picture: Masahiro Okumura..

ULNA Picture: Masahiro Okumura..

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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:

infections neoplasia inflammation

Puncturing:

a perfect aseptia is required 22-25G needle 2ml syringe 39


Elements to analyse:

amount of fluid appearance cytological analysis

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

protein content bacteriological culture test 40


Amount of fluid Appearance


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Treatment Strategy

Conservative therapy

remove the cause of the disease control pain and inflammation protect the damaged cartilage => a Combined Drug Therapy is needed

Surgical treatment

often last resort

when the control of pain becomes impossible

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Conservative Therapy

Supportive treatment:

Mild exercice is needed every day:

to maintain range of motion of joint to strengthen soft tissues around the joint to enhance the metabolic activity of cartilage

Weight control

to 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 physiology Control of Inflammation Modify the cartilage Matrix Metabolism

Long term treatment => drugs with minimal side effects are required 44

Conservative Therapy: Drugs (1)

Available drugs:

NSAIDs: oral & injectable DMOAs: oral & injectable (Disease-modifying osteoarthritis agents)

Steroids: oral & injectable Morphinics: oral & injectable Local anesthetics

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Conservative Therapy: Drugs (2)

All drugs are complementary:

Reduction of Reduction of Protection Adverse Pain Inflammation of cartilage effects ++, ++, NSAIDs 0/+ + short term short term ++, ++, DMOAs +++ 0 long term long term ++, Steroids +++ --++ temporary Morphinics ++ 0 0 + Local +++, 0 0 0 anesthetics short action Drugs

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Conservative Therapy: Drugs (3) CS

IL 1 beta

CS

Hyperpressure

Activation of chondrocytes

CS NSAID

Steroids

Increase of Metalloproteases

Increase of synthesis

NSAID CS

CS

Destruction of cartilage Matrix

PgE2

Inflammation

CS NSAID

CS = Chondroitin Sulfate (DMOA)

CS NSAID Steroids

Release of cartilage fragments Synthesis of proteases

IL 1 beta IL6 TNF alpha

Morphinics Local Anesth.

PAIN

Activation of synoviocytes

+m

r ac

ge a h op

s

47

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 48

Conservative Therapy: Drugs (5) Drugs

Chondroitine Sulfate

Available DMOAs: Pro

Cons

Recommendations

- Anti-inflammatory + - Needs 2 weeks to show - As soon as the begining of chondroprotective effect the treatment, in effects by oral route - The predominant - Highly degradated in the combination with pain killers proteoglycan in the matrix - Long term management digestive tract - Carry-over effect

Hyaluronic acid

- Lubrication role when injected in the joint

Glucosamine

- Lubrication role when injected in the joint - Resistant to digestive enzymes

- Difficult management of injections on the long term - More structural than anti-inflammatory effect - No direct study in small animals

- Injection at the begining of the treatment - Idem CS - May be completed with NSAIDs on the long term

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Surgical Treatment

Arthrodesis

Replacement arthroplasty

common procedure

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

Excisional arthroplasty

Easier, but functions reduced after surgery (except for the hip) 50

Surgical Treatment: Arhrodesis

Articular disintegration


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Conclusion

Joint diseases concern welfare and quality of live Easy and objective methods for diagnosis Treat the underlying diseases Restore joint function Combined therapy is needed for treatment, in addition to animal welfare & quality of life 52