MSK 5 Elbows OA DJD Flashcards by Kate Harvey

What are the normal microscopic layers of articular cartilage? (5-6)

Superficial zone
Transitional zone
Deep zone
Tidemark
Subchondral bone
Cancellous bone

The layers are characterized by differences in cell density, orientation, and ability to withstand various forces.

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Define Osteochondrosis

Development disorder of medium and large fast-growing dogs characterized by abnormal endochondral ossification of epiphyseal cartilage and growth plates.

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What is Osteochondritis dissecans?

A condition where the diseased articular cartilage becomes a loose flap.

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Describe the pathophysiology of OCD

Focal area of necrosis in epiphyseal cartilage canals, leading to cartilage ischemia and necrosis, which may result in thickened cartilage, inflammatory reactions in subchondral bone, and potential formation of cartilage flaps.

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What are the four risk factors for OCD?

Fast growth
Poor nutrition/wrong Ca:P ratios
Genetics
Trauma/overexercise

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In which joints does OCD occur in dogs?

Shoulder joint: caudocentral or caudomedial humeral head
Hock joint: lateral or medial trochlear ridge of talus
Stifle joint: medial or lateral femoral condyles
Elbow: medial or lateral distal humeral trochlea

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What are the components of elbow dysplasia?(4)

Ununited anconeal process
Fragmented medial coronoid process
OCD distal humeral condyles
Elbow incongruency

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What are the pros of radiography for diagnosing elbow dysplasia?

Cheaper
Easily/quickly accessible
Good visibility of united anconeal process on flexed lateral views

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What are the cons of radiography for elbow dysplasia?

Unable to visualize inside the elbow joint due to superimposition of structures.

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What are the pros of arthroscopy for elbow dysplasia?(3)

Direct visualization of defects
Ability to treat at the same time
Unparalleled visibility of joint/cartilage surfaces

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What are the cons of arthroscopy for elbow dysplasia?

Requires general anesthesia
User expertise needed
Limited visibility of elbow congruency
May miss low-grade OCD lesions

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What are the pros of CT for elbow dysplasia? (4)

Clear identification of anatomy
Ability to create 3D models
Identifies grade 1 OCD lesions
Assesses subchondral bone conditions

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What are the cons of CT for elbow dysplasia?

Increased cost
Requires referral
May still need arthroscopy afterward
Risk of false negatives for cartilage lesions

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What factors influence the management of FMCP in dogs? (3)

Severity of preexisting OA
Age of patient
Expected level of activity

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What provides the best prognosis for managing elbow dysplasia?

Early surgical treatment in young dogs with minimal OA and ongoing rehabilitation and preventative measures.

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What are some surgical options for elbow dysplasia? (4)

Fragment removal
Subtotal coronoid ostectomy
Various osteotomies
Canine unicompartmental elbow implants

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What is the salvage procedure for elbow dysplasia?

Arthrodesis, which alleviates pain but results in loss of function.

What are some alternative treatments for elbow dysplasia?

Intraarticular steroids
Intraarticular hyaluronic acid
Intraarticular plasma/platelet-rich plasma
IA stem cells
Acupuncture

Why are most elbow luxations lateral?

The distal slope and large size of the humeral trochlea prevent medial displacement of the radius and ulna.

What are potential long-term complications of chronic elbow luxation?

Osteoarthritis
Inability to reluxate
Muscle atrophy from disuse
Damage to surrounding soft tissue
Muscle contraction
Articular cartilage damage

What is Incomplete Ossification of Humeral Condyles (IOHC)?

A condition where the medial and lateral condyles fail to fuse, leading to structural weakness and potential for humeral condylar fractures.

What breeds are commonly affected by IOHC?

Spaniels
Labradors
English Pointers
German Shepherds
Rottweilers
Yorkies

What are the typical signs of IOHC? (3)

Persistent thoracic limb lameness
Pain on full extension or flexion
Non-responsive to NSAIDs

What causes persistent thoracic limb lameness and predisposes to humeral condylar fractures?

Micro movement between lateral and medial compartments

Pain on full extension or full flexion with carpus pronated, non-responsive to NSAIDs.

Which breeds are often affected by humeral condylar fractures?

Spaniels, Labradors, English Pointers, GSDs, Rottweilers, Yorkies ## Footnote Often bilateral, with other concurrent issues.

What is the most common type of fracture associated with the humeral condyle?

Lateral fractures ## Footnote More common due to anatomy/biomechanics – 30-60% of fractures.

How is a humeral condylar fracture diagnosed?

By radiographs: standard craniocaudal and flexed lateral views, and a 15 degree craniomedial to caudolateral oblique ## Footnote CT may be used for better sensitivity and specificity.

What is the best treatment recommendation for humeral condylar fractures?

Prophylactic surgical stabilization ## Footnote Conservative treatment is associated with high rates of fractures.

What is the most commonly used surgical method for humeral condylar stabilization?

Transcondylar cortical screw ## Footnote Use the largest one possible to reduce the chance of implant failure.

What is the grading system used for arthroscopic examination of cartilage pathology?

Modified Outerbridge score ## Footnote Ranges from normal (no visible pathology) to full thickness cartilage erosion.

What are the two main forms of joint incongruency in medial coronoid disease?

1. Abnormal/small curve of trochlea notch 2. Uneven alignment of articular surfaces of radius/ulna ## Footnote This may lead to humeroulnar conflict and joint instability.

What are the key components of the aetiopathogenesis of Medial Coronoid Disease?(4)

1. Complex polygenetics combined with 2. environmental variables Leads to 3. microfractures in subchondral bone due to 4. excessive mechanical loading.

Fill in the blank: Osteochondrosis is a developmental disorder characterized by _______.

[focal areas of reduced blood supply to an area of articular cartilage that results in abnormally thickened cartilage].

What are the four synovial joints often affected by OCD?

1. Shoulder joint (caudal humeral head) 2. Elbow (distal humerus) 3. Stifle (distal femur) 4. Hock (distal tibia) ## Footnote Includes medial and lateral condyles.

What is a Monteggia fracture?

A fracture of the proximal part of the ulna associated with radial head luxation ## Footnote Treated with open surgical reduction and stabilization.

What is the prognosis for traumatic elbow luxation dependent on? (6)

1. Severity of cartilage and soft tissue damage 2. Duration of luxation prior to repair 3. Degree of persistent instability 4. When rehabilitation is started 5. Owner compliance 6. If there are injuries elsewhere.

True or False: The medial collateral ligament is thought to be stronger than the lateral collateral ligament.

False ## Footnote The medial collateral ligament is considered weaker.

What are the basic principles of surgical arthrodesis?(6)

1. Careful planning 2. Removal of all cartilage at fusion sites 3. Close apposition of joint surfaces at a functional standing angle 4. Rigid internal fixation using compression 5. Use of cancellous bone graft 6. Careful preservation of soft tissue.

Fill in the blank: The final end stage result of Osteochondrosis is known as _______.

[OCD].

What are the indications for pancarpal arthrodesis?

1. Antebrachiocarpal joint involvement 2. Damage to accessory carpal ligaments 3. Severe DJD 4. Articular fracture that’s non-repairable.

What is the pathogenesis of OCD?

Disruption of anastomoses in focal areas causing ischemic cartilage necrosis ## Footnote May lead to necrotic areas replaced by fibrous tissue and cartilage fissuring.

What are the eight surgical techniques for medial elbow compartment disease?

1. Fragment removal 2. Subtotal coronoid ostectomy 3. Biceps ulnar release procedure 4. Radial osteotomy 5. Proximal abducting ulnar osteotomy (PAUL) 6. Dynamic proximal ulnar osteotomy 7. Distal dynamic ulnar ostectomy (DDUO) 8. Sliding humeral osteotomy.