SA Ortho

7 features of an imaging lesion description

Location
Size
Opacity
Shape
Structure
Margins
Number

Osteopaenia

Decrease in bone density

3 patterns of bone lysis

Geographic = large, defined area
Motheaten = multiple, ill-defined areas
Permeative = appears as if it is disolving

Sclerosis

Increase in bone density

How long does it take from disease onset for radiographic bone changes to be seen

>7d

How does nuclear scintigraphy work

I/v technetium 99 injection
Builds up in areas of increased blood supply (i.e. inflammation)
First 30min is soft tissue phase and then moves to bone

Myelography

Radiographic study where contrast is injected into subarachnoid space

Segmental fracture

Has one large fragment

Comminuted fracture

Has >2 fragments

Avulsion fracture

Fragment of bone pulled away by tendon/ligament attachment

4 forces acting on the bone

Tension = from muscle/tendon attachment
Axial compression = vertical from weight bearing
Bending = asymmetrical muscle contraction/limb at angle to ground
Torsion/rotation

Which force on the bone causes the most internal stress

Bending

3 phases of bone healing

Inflammatory phase (haematoma formation)
Reparative phase (granulation tissue - CT and fibrocartilage)
Remodelling phase (Haversian remodelling)

What value determines which type of tissue can form in a fracture gap

Strain (w)

Calculation for strain (w) =

Change in length of fracture gap / original length of fracture gap

4 questions for decision making in fracture cases

Can it be anatomically reconstructed?
What is the condition of the soft tissues?
Will the fracture take a long time to heal/be subject to large forces?
Will the repair method suit the animal/owner?

What method of fracture repair should be used if the fracture can be anatomically reconstructed

Open reduction internal fixation (ORIF)

What methods of fracture repair should be used if the fracture cannot be anatomically reconstructed

External fixators
Minimally invasive plate osteosynthesis (MIPO)

Wolff's law

Bone remodels in response to forces on it (i.e. if to rigid a plate is used, the bone will resorb - stress protection)

What classification system is used for growth plate fractures

Salter-Harris

Treatment of Salter-Harris type I and II fractures

Small, less rigid implants

Treatment of Salter-Harris type III and IV fractures

Rigid stabilisation

Which types of Salter-Harris fractures involve the articular surface

III and IV

Treatment of fractures involving the articular surface

Want to prevent callus formation = rigid internal fixation with compression
Want animal to use limb to prevent stiffness

2 types of plates used in fracture repair

Dynamic compression plates (DCP)
Locking compression plates (LCP)

How many screws do you want to place in each significant fragment when using a DCP

3

Which type of plate used for fracture repair is more stable

Locking compression plate

3 ways of using dynamic compression plates

Compression plate = axial compression (transverse fractures)
Neutralisation plate = does not compress but neutralises other forces
Bridging plate = minimal fragment contact, plate takes full weight

3 types of screws used in fracture repair

Cortical (wide core, thin threads) - stronger
Cancellous (thin core, wide threads) - better grip
Locking (has threads on screw head)

2 ways of using screws in fracture repair

Position screw = hold plate onto bone/hold fragments together
Lag screw = provides compression

2 methods of insertion of intramedullary pins

Normograde = inserted at end of bone
Retrograde = inserted at fracture site (increased risk of entering joint space)

In which bone should intramedullary pins not be used

Radius

What force are intramedullary pins best at resisting

Bending

Which force are intramedullary pins not good at resisting

Rotation

Treatment of avulsion fractures

Pins and tension band wire

Causes of the pain associated with arthritis

Mechanoreceptors in the joint capsule/ tendons/ligaments
Free nerve endings in all tissue except cartilage
Inflammation = sensitisation of receptors

Diagnosis of OA

History - lameness, stiffness
Physical exam - range of movement, swelling, pain
Radiographs
Arthroscopy
Advanced imaging

Conservative options for OA treatment

NSAIDs
Weight loss
Exercise modification
Physiotherapy
Pentosan polysulphate/glucosamine/fish oil
Joint injections (steroids, hyaluronic acid, platelet rich plasma, stem cells)
Acupuncture/laser therapy

Surgical options for OA treatment

Excision arthroplasty
Joint replacement
Arthrodesis

Ddx for multiple limb lameness

OA
IM joint disease
Panoestoepathy
Metaphyseal osteopathy
Nutritional bone disease
Neoplasia
(Osteochondrosis)
(Craniomandibular osteopathy)
(Osteomyelitis)
(Septic arthritis)

Pathogenesis of IMPA

Immune complexes accumulate in the joint space = complement activation = cytokine release and tissue damage = neutrophil attraction = further cytokine damage

3 types of IMPA

Type 1 = idiopathic (most common)
Type 2 = secondary to another infection
Type 3 = secondary to GI disease
Type 4 = secondary to neoplasia

Signs of IMPA

Usually adult animals
Stiffness
Pyrexia, lethargy
+/- lameness
Joint effusions
Joint pain

Diagnosis of IMPA

Arthrocentesis of >3 joints
Radiographs (joints and thorax in case of neoplasia)
U/S (to look for primary causes)
Bloods

Idiopathic IMPA treatment

Immunosuppressants (prednisolone +/- azathioprine/ciclosporin)

IMPA prognosis

Fair - guarded

Signs of panosteitis

Young, large breed dogs
Shifting lameness
Long bone pain
Pyrexia

Pathogenesis of panosteitis

Endosteal new bone formation of unknown aetiology

Diagnosis of panosteitis

Radiography - increase in medullary density = 'thumb print' lesions

Treatment of panosteitis

Analgesia (NSAIDs)
Supportive care

Prognosis for panosteitis

Good but may recur

Signs of metaphyseal osteopathy

Young dogs
Acute onset lameness and reluctance to move
Metaphyseal swelling
Pyrexia
+/- Diarrhoea

Diagnosis of metaphyseal osteopathy

Radiography - radiolucent lines parallel to physis

Treatment of metaphyseal osteopathy

Analgesia (NSAIDs)
Supportive care

Predisposing factor for nutritional bone disease in small animals

Meat only diet

Signs of nutritional bone disease

Pain and lameness
Reluctance to move
May have multiple fractures

Diagnosis of nutritional bone disease

Bloods - normal Ca, high PTH
Radiography - poor skeletal mineralisation, multiple fractures

Treatment of nutritional bone disease

Feed normal diet
Analgesia
Correct fractures if present

Hypertrophic osteopathy (Marie's disease)

Paraneoplastic syndrome associated with thoracic/abdominal neoplasia

Signs of hypertrophic osteopathy/Marie's disease

Lameness/reluctance to move
Firm swelling of distal limb
Signs of the underlying neoplasia (e.g. cough)

Diagnosis of hypertrophic osteopathy/Marie's disease

Radiography - periosteal new bone growth of distal limbs (and thoracic/abdominal mass)

Signs of osteosarcoma

Single limb lameness (may be multiple if metastasised)
Pain on palpation

Treatment of osteosarcoma

Amputation/limb sparing surgery and chemotherapy
Euthanasia if metastasised

Prognosis for osteosarcoma

Poor

Signs of septic/infective arthritis

Severe lameness
Pyrexia, lethargy
Joint effusion and pain
Limb oedema

Diagnosis of septic arthritis

Arthrocentesis for cytology and culture

Treatment of septic arthritis

Antibiotics
+/- joint lavage

Prognosis for cases of septic arthritis

Based on joint health prior to infection

Signs of osteomyelitis

Acute or chronic presentation
Acute = lameness and swelling
Chronic = muscle atrophy and contracture
Draining sinus
Pyrexia

Diagnosis of osteomyelitis

Signs
Radiography

Treatment of osteomyelitis

Antibiotics
If due to open fracture will likely require revision surgery

Prognosis of osteomyelitis

Variable - based on bone healing ability

Pathogenesis of osteochondrosis

Failure of endochondral ossification

When does osteochondrosis become osteochondrosis dissecans

When the cartilage forms a flap

Common locations of osteochondrosis in small animals

Humeral head
Medial part of humeral condyle in elbow
Femoral condyle in stifle
Trochlear ridge of talus

Diagnosis of osteochondrosis

Radiographs - will see flattening of joint surface or if OCD present, will see cartilage flap

Treatment of osteochondrosis

Remove cartilage flaps/fragments if symptomatic

Prognosis of osteochondrosis

Better for shoulder
Will go on to develop OA

Westie Jaw AKA

Craniomandibular osteopathy (CMO)

Pathogenesis of craniomandibular osteopathy

Idiopathic proliferative disease of the mandibular tympanic bullae and long bones

Signs of craniomandibular osteopathy

Puppies (4-7mth)
Oral pain
Oral swelling
Decrease appetite/dysphagia

Treatment of craniomandibular osteopathy

Analgesia
Nutritional support

Ddx for shoulder pain

Soft tissue injuries
Biceps tendon injury
Infraspinatus contracture
Osteochondritis/OCD
Fracture
OA

Diagnosis of ligament injuries

Manipulation - looking for instability
Radiographs (esp. stressed views)

Treatment of ligament injuries

If joint still feels stable = rest, NSAIDs, cold packing, massage, Robert-Jones bandage
If joint feels unstable = surgery:
Primary ligament repair
Internal ligament splinting/replacement
Joint modification
Arthrodesis

Diagnosis of soft tissue injuries of the shoulder

Increased abduction angles (GA)
Cranial drawer (GA)
Arthoscopy

Diagnosis of biceps tendon injuries

Biceps tendon test - pain on shoulder extension and elbow flexion

Treatment of biceps tendon injuries

Conservative = prolonged rest, NSAIDs
Intra-articular steroid injection
Surgical release of tendon origin

Diagnosis of infraspinatus contracture

Classic posture = flexed elbow with limb externally rotated

Treatment of infraspinatus contracture

Surgical - cut the tendon

Prognosis for infraspinatus contracture

Good if tendon cut

Diagnosis of osteochondritis in the shoulder

Pain on manipulation (esp. flexion)
Radiography and arthrogram (contrast radiography)

Treatment of osteochondritis of the shoulder

Conservative if not too lame
Surgery to remove cartilage flaps

Prognosis of osteochondritis of the shoulder

Good (esp. if

Treatment of mineralisation of the soft tissues of the shoulder

Only if causing lameness (often incidental finding)
Conservative
Surgical/arthroscopic removal

Ddx for lameness originating from the elbow in small animals

Elbow dysplasia
Elbow luxation (congenital vs traumatic)
OA
Fractures

Medial compartment disease AKA (orthopaedic condition)

Elbow dysplasia

Above what BVA elbow score should dogs not be bred from

2

Signs of elbow dysplasia due to fragmented medial coronoid process

4-7mth old
Forelimb lameness
Pain on manipulation (flexion and rotation)
Mild effusion

Treatment of elbow dysplasia due to fragmented medial coronoid process

Conservative
Arthrotomy or arthroscopy to remove fragment