Neonate orthopaedic disease

Question 1

6 neonatal orthopaedic diseases

Answer 1

1) Incomplete ossification of cuboidal bones
2) Septic arthritis / physitis / osteomyelitis (SAPO)
3) Physitis
4) Physeal fracture
5) Angular Limb deformity
6) Flexural deformity

Question 2

Incomplete ossification of the carpus - which bones?

Answer 2

• radial, intermediate, ulnar, 2nd, 3rd, 4th carpal bones

Question 3

Incomplete ossification of the tarsus - which bones?

Answer 3

• central 2nd, 3rd, 4th tarsal bones

Question 4

Skeletal formation in utero (re cartilage ossification)

Answer 4

▪Skeleton formed as a cartilage in utero
▪Normally ossify in last 2-3 months of gestation (months 9-11)

Question 5

Which foals are affected by incomplete ossification of cuboidal bones?

Answer 5

• premature/dysmature foals

Question 6

What can cause incomplete ossification of cuboidal bones?

Answer 6

During gestation:
- placentitis
- colic
- abnormal positioning

Question 7

How do bones ossify/mineralise? (i.e. which direction?)

Answer 7

• from the centre outwards

Question 8

What can incomplete ossification of cuboidal bones cause at birth?

Answer 8

• peri-articular laxity

Question 9

Treatment of incomplete ossification of cuboidal bones

Answer 9

▪Excess exercise may cause damage to soft cartilage
▪Lead to joint and limb malformations

Therefore,
▪ Restrict exercise
▪ Splint limbs if laxity exists
▪ Wait for bones to ossify
▪ Keep in with nice soft bed
▪ Gradually decrease splints and increase exercise as the bones get stronger

Question 10

Radiographic findings of incomplete ossification

Answer 10

• curved edges of bone
• big spaces where bone should be that are cartilaginous

Question 11

What is physitis?

Answer 11

= Inflammation of the physis (growth plate) at the end of a long bone

Question 12

Closure time of the distal radius

Answer 12

24 months

Question 13

Closure time of the distal metacarpus (M3)

Answer 13

6-9 months

Question 14

Closure time of the distal tibia

Answer 14

17-24 months

Question 15

Closure time of the distal metatarsus (M3)

Answer 15

9-12 months

Question 16

When will the growth phase of the distal metacarpus be active up until?

Answer 16

4 months

Question 17

When will the growth phase of the distal radius be active up until?

Answer 17

18-20 months

Question 18

When will the growth phase of the distal tibia be active up until?

Answer 18

18-20 months

Question 19

When can physitis occur?

Answer 19

• anytime until closure of the growth plates

Question 20

Does most of the long bone growth happen during resting or load bearing in foals?

Answer 20

• resting

Question 21

Physitis potential triggers

Answer 21

▪Rapid growth
- specific growth phases / increased feed intake

▪Trauma to the physis (? type 5 Salter-Harris injury)
- indirectly through exercise, e.g. running up and down the fence line all day following the mare
- indirectly through severe contra-lateral limb lameness (increased weight bearing in non-lame limb)
- directly through external injury

▪Genetic predisposition

Question 22

Clinical signs of physitis

Answer 22

▪ Heat
▪ Swelling
▪Pain on palpation ▪Possibly lameness

Question 23

Signalment of physitis

Answer 23

▪Distal metacarpus 3-6mo foals
▪Distal radius yearlings
▪Commonly bilateral

Question 24

Physitis - radiographs

Answer 24

• Widening of the growth plates
• Sclerosis around the growth plates
• Periosteal new bone with bridging
  – Risk of angular limb deformities (ALD)

Question 25

Physitis - tx

Answer 25

• Exercise restriction
• Analgesia (as a painful and inflammatory condition, meloxicam is the best option for foals)
• Correction of underlying cause (e.g. reduce feed intake, etc)

Question 26

Salter-Harris fracture type 1

Answer 26

• Fracture happens across the growth plate
• Doesn’t go into the bone above or below
• Made of cartilage hence a weak point

Question 27

Salter-Harris fracture type 2

Answer 27

• Fracture goes across the growth plate and exits through the metaphysis

Question 28

Salter-Harris fracture type 3

Answer 28

• Fracture goes across the growth plate and goes through the joint surface

Question 29

Salter-Harris fracture type 4

Answer 29

• Fractures of the epiphysis extending through the articular cartilage, epiphysis, physis and metaphysis
• i.e. doesn’t start across the physis

Question 30

Salter-Harris fracture type 5

Answer 30

• Crushing of the growth plate - epiphysis crushed into the physis

Question 31

What is the most common physical fracture?

Answer 31

• Salter-Harris type II

Question 32

Physeal fracture tx

Answer 32

▪Conservative management - cast coaptation & confinement ▪Surgical correction – internal fixation
▪Damage to physis creates risk of growth deformities
- ALD or flexural deformity
– ALD if 1 side of the bone stops growing but the other side doesn’t

Question 33

Why are the front legs more commonly affected by physitis?

Answer 33

• because they bear more weight than the back legs

Question 34

Most common cause of a Salter-Harris type II fracture

Answer 34

• being trodden on by the mare