MSK 5 Elbows OA DJD Flashcards
What are the normal microscopic layers of articular cartilage?
- 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.
Define Osteochondrosis
Development disorder of medium and large fast-growing dogs characterized by abnormal endochondral ossification of epiphyseal cartilage and growth plates.
What is Osteochondritis dissecans?
A condition where the diseased articular cartilage becomes a loose flap.
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.
What are the four risk factors for OCD?
- Fast growth
- Poor nutrition/wrong Ca:P ratios
- Genetics
- Trauma/overexercise
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
What are the components of elbow dysplasia?
- Ununited anconeal process
- Fragmented medial coronoid process
- OCD distal humeral condyles
- Elbow incongruency
What are the pros of radiography for diagnosing elbow dysplasia?
- Cheaper
- Easily/quickly accessible
- Good visibility of united anconeal process on flexed lateral views
What are the cons of radiography for elbow dysplasia?
Unable to visualize inside the elbow joint due to superimposition of structures.
What are the pros of arthroscopy for elbow dysplasia?
- Direct visualization of defects
- Ability to treat at the same time
- Unparalleled visibility of joint/cartilage surfaces
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
What are the pros of CT for elbow dysplasia?
- Clear identification of anatomy
- Ability to create 3D models
- Identifies grade 1 OCD lesions
- Assesses subchondral bone conditions
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
What factors influence the management of FMCP in dogs?
- Severity of preexisting PA
- Age of patient
- Expected level of activity
What is the best prognosis for managing elbow dysplasia?
Early surgical treatment in young dogs with minimal OA and ongoing rehabilitation and preventative measures.
What are some surgical options for elbow dysplasia?
- Fragment removal
- Subtotal coronoid ostectomy
- Various osteotomies
- Canine unicompartmental elbow implants
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?
- 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
Often bilateral, with other concurrent issues.
What is the most common type of fracture associated with the humeral condyle?
Lateral fractures
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
CT may be used for better sensitivity and specificity.
What is the best treatment recommendation for humeral condylar fractures?
Prophylactic surgical stabilization
Conservative treatment is associated with high rates of fractures.
What is the most commonly used surgical method for humeral condylar stabilization?
Transcondylar cortical screw
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
Ranges from normal (no visible pathology) to full thickness cartilage erosion.
What are the two main forms of joint incongruency in medial coronoid disease?
- Abnormal/small curve of trochlea notch
- Uneven alignment of articular surfaces of radius/ulna
This may lead to humeroulnar conflict and joint instability.
What are the key components of the aetiopathogenesis of Medial Coronoid Disease?
Complex polygenetics combined with environmental variables
Leads to microfractures in subchondral bone due to 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?
- Shoulder joint (caudal humeral head)
- Elbow (distal humerus)
- Hock (distal tibia)
- Distal femur (Stifle)
Includes medial and lateral condyles.
What is a Monteggia fracture?
A fracture of the proximal part of the ulna associated with radial head luxation
Treated with open surgical reduction and stabilization.
What is the prognosis for traumatic elbow luxation dependent on?
- Severity of cartilage and soft tissue damage
- Duration of luxation prior to repair
- Degree of persistent instability
- When rehabilitation is started
- Owner compliance
- If there are injuries elsewhere.
True or False: The medial collateral ligament is thought to be stronger than the lateral collateral ligament.
False
The medial collateral ligament is considered weaker.
What are the basic principles of surgical arthrodesis?
- Careful planning
- Removal of all cartilage at fusion sites
- Close apposition of joint surfaces at a functional standing angle
- Rigid internal fixation using compression
- Use of cancellous bone graft
- 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?
- Antebrachiocarpal joint involvement
- Damage to accessory carpal ligaments
- Severe DJD
- Articular fracture that’s non-repairable.
What is the pathogenesis of OCD?
Disruption of anastomoses in focal areas causing ischemic cartilage necrosis
May lead to necrotic areas replaced by fibrous tissue and cartilage fissuring.
What are the eight surgical techniques for medial elbow compartment disease?
- Fragment removal
- Subtotal coronoid ostectomy
- Biceps ulnar release procedure
- Radial osteotomy
- Proximal abducting ulnar osteotomy (PAUL)
- Dynamic proximal ulnar osteotomy
- Distal dynamic ulnar ostectomy (DDUO)
- Sliding humeral osteotomy.
