Angular limb deformities

Question 1

What is an ALD?

Answer 1

• a deviation from the long axis of the limb in the frontal plane
  – observed when foal viewed from in front or behind

Question 2

What 3 criteria are ALD described according to?

Answer 2

1. Direction of deviation - valgus/varus
2. Centre of deviation - fetlock/carpus/tarsus etc
3. Severity - angle of deviation

Question 3

Valgus

Answer 3

• limb deviates outwards (laterally)

Question 4

Varus

Answer 4

• limb deviates inwards

Question 5

Aetiology

Answer 5

Congenital (present from birth)
- periarticular laxity
- incomplete ossification of cuboidal bones
- uterine malpositioning

Acquired (asymmetrical growth across physis)
- physitis
- direct trauma

Question 6

Examination

Answer 6

▪ Static
- Stand in front / behind
- assess severity
▪Dynamic
- Following the mare
- Can be tricky as don’t walk in a straight line
▪ Manipulation
- Peri-articular laxity

Question 7

Radiography

Answer 7

▪Origin of the deviation ▪Severity – measure angle
– Allows most accurate measurement of the angles
▪Incomplete ossification

Question 8

Conservative Treatment - Congenital

Answer 8

▪Incomplete ossification – box rest
▪Peri-articular laxity (but normal ossification) – box rest with controlled exercise

Question 9

Conservative Treatment – Acquired

Answer 9

▪Valgus
- Trim lateral hoof wall
- Extend medial hoof wall
▪Varus
- Trim medial hoof wall
- Extend lateral hoof wall

Gentle exercise on firm flat surfaces

Question 10

Surgical Treatment - indications

Answer 10

▪Severe deformity
▪Conservative treatment failed
▪When approaching age of physeal growth cessation
- distal metacarpus/tarsus: 4 months
- distal radius / tibia: 18 months
▪Persistent ulna
- Usually in miniature horses

Question 11

Surgical Treatment – Growth Retardation

Answer 11

▪Inhibit growth on long side of limb
- Allows the other side to catch up
▪Transphyseal bridge
- screws & wire (acts as an anchor)
- transphyseal screw

Question 12

Implant removal

Answer 12

▪If left in too long deviation will over correct ▪Regular re-evaluation required
- approx. every 2 weeks
▪Remove implant when almost straight (85-95% straight)
- straightening will continue a bit once implants removed

Question 13

Surgical Treatment – Growth Acceleration

Answer 13

▪Periosteal Strip
▪Periosteum on short side of limb transected transversely
- ‘releases’ the limb to grow faster
▪Lack of evidence of efficacy