Fetlock And Pastern

Question 1

What is a typical feature of failure of the suspensory apparatus at the fetlock?

Answer 1

Dropped fetlock - hyperextension

Question 2

What are the predilection sites for OCD in the fetlock?

Answer 2

Sagittal ridge of MC3
Palmar proximal phalanx
Subchondral bone cysts

Question 3

OCD in the fetlock

Answer 3

Young warmbloods horses
Acute - joint effusion and lameness in multiple joints

Sites- Sagittal ridge of MC3, palmar P1, Subchondral bone cysts

Dx: radiography and US

Tx: arthroscopy - remove fragments and lavage
Manage nutrition

Question 4

Subchondral cysts associated with OCD

Answer 4

Uncommon

Associated with OCD

Dx: radiography
Tx: arthroscopy - drill, fill cyst or inject corticosteroids

Px poor for cysts, good for fragments

Question 5

Subchondral bone pain

Answer 5

All athletic horses
- Subchondral bone becomes necrotic due to secondary trauma

Sites - distal metacarpal condyles (palmar osteochondral disease) & Sagittal groove = pre-fracture pathology

Dx: MRI best - other methods unreliable
Usually positive response to a low 4 point nerve block

Tx: rest, IRAP, PRP, lag screws

Question 6

What fractures are related to stress remodelling?

Answer 6

Sagittal metacarpal / metatarsal condylar fractures
- secondary to palmar osteochondral disease

Sagittal proximal phalanx fracture
Proximal sesamoidean bone fracture

Question 7

Metacarpal condylar fractures

Answer 7

Common articular fracture of MC3 due to stress remodelling

Occur at the parasagittal groove

• laterally - more common - Sagittal fracture
• medially - less common - spiral fracture

Question 8

Proximal phalanx fractures

Answer 8

Common articular fracture seen due to stress remodelling

Occur at the Sagittal groove of P1

Question 9

What conditions of the fetlock do you need to use a dorsal splint for?

Answer 9

Proximal sesamoid bone complete fractures
Suspensory ligament ruptures
SDFT tendon rupture

Question 10

What fractures of the fetlock region do you need lateral and medial splints for?

Answer 10

Sagittal fractures of MC3 / MT3

Sagittal fractures of P1

Question 11

What fractures indicate euthanasia?

Answer 11

Open / comminuted and displaced
Markedly unstable limb
Not amenable to surgical fixation

Question 12

What fractures are amenable to surgical fixation?

Answer 12

Lag screw fixation - most common

• Sagittal MC3 / MT3 lateral condylar
• Spiral MC3 / MT3 medial condylar
• Sagittal fracture of the proximal phalanx
• Frontal fracture of the proximal phalanx

Plate fixation - for comminuted fractures

• Spiral MC3 / MT3 medial condylar
• comminuted Proximal phalanx

16 weeks fracture healing with lag screw fixation

Question 13

What fractures can be managed conservatively?

Answer 13

Incomplete

Non-displaced

Question 14

Fetlock OA

Answer 14

Secondary to

• repetitive motion
• OCD
• Subchondral bone disease - palmar osteochondral disease
• Fracture

Dx: bilateral lameness, worse on the hard and after flexion
Joint effusion
Positive response to intra-articular anaesthesia
Rx - signs of OA

Tx: intra-articular methylprednisolone acetate
PBZ / suxibuzone systemic
Hyaluronic acid IA or systemic
PRP / IRAP IA

Arthroscopy to remove damaged cartilage in high motion joints
- metacarpophalangeal joint
Arthrodesis in low motion joint - PIPJ / DIPJ
- IA ethanol or internal fixation

Question 15

What is the correct hoof wall length?

Answer 15

2 and 1/2 times greater at the toe than the heel

Question 16

Broken back hoof pastern axis

Answer 16

Corrective shoeing required

Results in flat sole and swollen frog

Question 17

Broken forward HPA

Answer 17

Reduce the length the heel

Fit a toe extension