2.23 Developmental Abnormalities of Tendons

What is the term for a condition where the limb deviates from normal vertical alignment?

Flexural deformity.

What are the two types of flexural deformities in horses?

Laxity (lengthening) and "contracted tendons" (shortening).

What are the two categories of flexural deformities?

Congenital and acquired.

What are examples of congenital flexural deformities?

1. Flexural laxity

2. Hyperflexion

3. Rupture/elongation of the common digital extensor tendon

What are examples of acquired flexural deformities?

1. Club foot

2. Flexural deformity in metatarso/carpophalangeal joint

What is the cause of flexural laxity?

• Quite frequent problem in premature foals. Intrauterine infection, mother infection.

• In older horses, previous injuries or diseases, nutritional deficiencies, lack of exercise, or normal ageing.
  

What are the common signs of congenital flexural laxity in foals?

Overextension, toe elevation, and contact of the fetlock joint with the ground.

What causes congenital flexural laxity in foals?

Intrauterine infection, mother infection, and premature birth.

What is the diagnosis of flexural laxity?

X-ray: Check skeletal maturity – shows insufficient mineralization and delayed long bone development.

What is the recommended treatment for flexural laxity?

Box stay, moderate exercise, light bandaging, and shoeing with heel elongation.

When is euthanasia indicated for flexural laxity?

Severe insufficient mineralisation.

Why is surgery contraindicated in most cases of flexural laxity?

Surgery is usually not needed, and severe cases with insufficient mineralization may require euthanasia.

How can flexural laxity be prevented?

• Prevent premature delivery of foal by proper care of the mare. Premature foals should not be allowed to stand up.

• With older horses, prompt attention to tendon injuries, good nutrition, and sufficient exercise will help prevent development of weak or lax flexor tendons.

What is the main clinical sign of hyperflexion in foals?

Flexion of the carpal (preying mantis) or fetlock joints (knuckling), with an inability to stand or nurse.

What are possible causes of hyperflexion in foals?

Infection of the mother, intrauterine mispositioning, and unknown factors.

How is hyperflexion diagnosed?

CS, x-ray.

How is hyperflexion treated in foals?

Reshaping, moderate exercise, NSAIDs, oxytetracycline, and surgery to cut flexor tendons (flexor carpi ulnaris/ulnaris lateralis).

What is the effect of oxytetracycline in the tendons?

Binds calcium and causes lengthening.

What occurs when there is a rupture or elongation of the common digital extensor tendon?

Inability to extend the digit and step on the hoof, with over-knuckling and swelling.

What is the diagnosis for rupture or elongation of the common digital extensor tendon?

CS, USG. Free ends of tendon palpated.

What is the best treatment for ruptured or elongated common digital extensor tendon in foals?

Casting or splinting for 2-3 weeks and allowing standing to improve function.

What is club foot in horses?

A condition where the deep digital flexor tendon (DDFT) shortens, causing the hoof to rotate downward.

What age group is most affected by club foot?

Suckling foals between 4 weeks to 6 months.

What is the main cause of club foot in foals?

Overfeeding, mineral imbalances, sudden nutritional changes, hyperparathyroidism, exercise, or trauma.

How can overfeeding lead to club foot?

High energy and protein diet → bone grows faster than tendon.

What are the clinical signs of club foot?

High heels, walking on toes, and lack of contact between the hoof's solar surface and the ground.

What are the stages of club foot?

Stage I: hoof wall <90°; Stage II: >90° - bad prognosis.

How is club foot diagnosed?

X-ray and observation of sole elevation.

What is the treatment for club foot?

Hoof correction, shoeing (e.g., Dallmer shoe), and surgery such as desmotomy of ALDDFT or elongation of the DDFT.

How is club foot prevented?

Take off pasture, reduce energy/protein consumption. Keep on hard ground, hoof trimming.

What is flexural deformity in the metacarpophalangeal joint (MTCP)?

A condition in older foals (10-18 months) involving shortening of the suspensory apparatus and flexor tendons.

What are the main causes of flexural deformity in the MTCP joint?

Poor ossification, overfeeding, nutritional changes, mineral imbalances, and trauma.

What are the clinical signs of flexural deformity in MTCP?

Hoof has normal appearance, but straight, upright appearance of pastern → over knuckling

How is flexural deformity in MTCP diagnosed?

CS.

How is flexural deformity in the MTCP joint treated?

• Heel support with a wedge

• Transecting accessory ligaments of the DDFT and SDFT.

What tendon also originates in the same place as the long digital extensor tendon?

Lateral digital extensor tendon.

For flexural laxity, which bones do you look at on x-ray for mineralisation?

Cuboidal bones.

What type of support bandage can you use?

Robert-Jones.

What is the problem with bandaging?

Pressure necrosis, so have to change regularly.