Flexural deformities in foals

Question 1

How are flexural deformities named and assesed?
In what limbs are the common in?

Answer 1

• Named according to the joint involved.
• Occur in the sagittal plane –> assessed by viewing from side on.
• More common in forelimbs.
• Commonly bilateral.
• Congenital or acquired.
• Hyperextension (laxity) or hyperflexion (contracture).
• Radiography may assist diagnosis but is not always required.

Question 2

In which limb and locations are congenital hyperextension common?
What do they look like?
Why do they occur?
How are they treated?

Answer 2

• Usually distal limb – fetlock and phalangeal joints.
• Toe is elevated and palmar/plantar fetlock is sunken.
• Due to flaccidity of flexor muscles after birth.
• Usually self corrects within a few weeks. → confine to a small grass pen.
• Skin abrasions may occur on palmar/plantar fetlock. → protect with bandages.
• Glue on heel extension shoes may be required

Question 3

What probles during birth and after birth do congeital hyperflexion deformities cause?
What joints do thye commonly affect?

Answer 3

• May cause dystocia
• May prevent foal from standing
• Occurs at coffin, pastern, fetlock, carpal or tarsal joints

Question 4

What is the medical treatment for congenital hyperflexion?

Answer 4

• Light exercise – spontaneously resolve in a few days.
• 3g oxytetracycline in 500ml saline slow IV.
  
  • within a few days of birth.
  • inhibits tractional structuring of collagen fibrils. → tendons & ligaments more susceptible to elongation during normal weight bearing.
• Toe extensions and heel reduction.
  
  • stretches musculotendinous unit during weight bearing.
• NSAIDs (and omeprazole).
• Splints or casts.
  
  • encourages relaxation of the musculotendinous unit.

Question 5

What cause acquired hyperflexion?
Describe two causes of acquired hyperflecion

Answer 5

Pain cause flexion withdrawal reflex and subsequent muscle contraction

1) Rapid bone growth with tendons unable to keep up
→ functional shortening of tendons
→ resulting tension in tendon is painful

2) Specific injury e.g. osteochondrosis, fracture, septic arthritis, foot abscess

Question 6

When does Acquired coffin joint contracture occur?
What is the common name for it?
What bones and tendons are affected?
What are the two types?

Answer 6

Club foot

1-4 months old
→ Metacarpal / tarsal bones growing rapidly
→ Functional shortening of DDFT
Stage 1: dorsal hoof wall has not past vertical – good prognosis
Stage 2: dorsal hoof wall has progressed past vertical – guarded prognosis

Question 7

What is the medical treatment for acquired coffin joint contracture?

Answer 7

• Toe extensions and heel reduction.
  → stretches DDFT musculotendinous unit during weight bearing.
• NSAIDs (and omeprazole).
• Reduce foals growth rate by reducing nutrition
  → reduce feed to foal and mare
  → early weaning
• Address other causes of pain
• Suitable for stage 1 only

Question 8

What is the surgical management for acquired coffin joint contracture?

Answer 8

Stage 1: Desmotomy of the accessory (check) ligament of the DDFT
→ proximal cannon under short G.A.
→ good prognosis as an athlete

Stage 2: Tenotomy of DDFT
→ mid cannon or palmar pastern
→ guarded prognosis as an athlete

Performed in addition to medical therapies

Question 9

when does acquired fetlock joint contracture occur?
What bones and tendons are involved?
What are the three types?

Answer 9

10-18 months old
→ Radius / tibia growing rapidly
→ Functional shortening of SDFT and suspensory ligament.
Stage 1: Fetlock remains behind vertical
Stage 2: Fetlock positioned in front of vertical, but can move behind vertical during weight bearing.
Stage 3: Fetlock positioned in front of vertical always.

Question 10

What is the medical management for acquired fetlock joint contracture?

Answer 10

• Toe extensions
• NSAIDs (and omeprazole).
• Reduce foals growth rate by reducing nutrition
  → reduce feed to foal and mare
  → early weaning
• Splint to force fetlock into extension
• Address other causes of pain
• Suitable for stages 1 only.

Question 11

What is the surgical treatment for acquired fetlock joint contracture?

Answer 11

• Careful palpation under G.A. with limb in full extension reveals which structure(s) is causing contracture.
• Procedure performed depends on structure(s) involved and severity
• SDFT
  → Desmotomy of the accessory (check) ligament of the SDFT
  → SDFT Desmotomy (guarded for athletic use)
• DDFT
  → Desmotomy of the accessory (check) ligament of the DDFT
  → DDFT Desmotomy (guarded for athletic use)
• Suspensory ligament
  → Suspensory ligament Desmotomy (guarded for athletic use)
• Performed in addition to medical therapies