July 2026 Newsletter

Before we get started, I wanted to quickly introduce myself. I’m Will, one of the newest members of the Guasco & Associates team. recently completed a two-year internship at Newmarket Equine Hospital, gaining valuable experience in orthopaedics, diagnostic imaging, emergency medicine and surgical case management. National Hunt racing has always been a particular passion of mine, and having spent time with Paolo and the team as a veterinary student over the years, it’s a real pleasure to return to a practice and an area that already feels familiar. I’m looking forward to meeting many more of you over the coming months as we build up to hopefully another successful season for our clients…

With foaling season now largely behind us (thank God!), most foals are well into their first few months of life. By now, many of the early decisions surrounding fetlock deformities will already have been made. As attention begins to shift towards the knees, it seems like the perfect opportunity to continue our breeding theme by taking a closer look at the growing foal—and one of the most common developmental conditions we encounter: angular limb deformities.

Crooked Legs in the Growing Foal

Crooked Legs in the Growing Foal

Foal limbs can range from the normal to the extreme… I was fortunate enough to witness plenty of both and everything in between during my time at NEH (see below!) 

What is an angular limb deformity?

An angular limb deformity (ALD) is simply a sideways deviation of the limb below a joint.  If the limb angles outwards, it’s called valgus. For example, the poor foal pictured above right can be described as having a carpal valgus. If it angles inwards, it’s called varus. Some of you may be more familiar with terms such as knock-kneed, pigeon-toe’d or bow-legged. 

The knee (carpus) and fetlock are the most common places we see these deformities, although the hock can also be affected. More than one limb and more than one joint can be affected in the same horse in various combinations. The classic ‘windswept’ foal is a result of varus on one limb and valgus on the opposite.  

Why do they happen?

There isn’t one simple answer.

Some foals are born with crooked limbs because they were premature or because the small bones within the knee and hock haven’t fully ossified before birth.

Others develop deformities during growth when one side of the growth plate grows faster than the other. Genetics, nutrition, exercise and trauma can all contribute. 

Will they grow out of it?

Sometimes.

Many mild deformities improve naturally during the first few weeks of life, which is why we don’t rush every foal into surgery.

However, some deformities worsen as the foal grows, and these are the ones we need to identify early.

Regular examinations are often far more useful than a single assessment because we’re interested in the direction the limb is heading, not just what it looks like today.

How do we assess them?

Watching the foal walk is just as important as looking at it standing still.

We’ll assess:

• where the deformity originates
• whether the limb can be straightened manually
• how the foot lands
• whether both limbs are affected equally

Radiographs are useful when the deformity is more severe or if surgery is being considered, helping us identify exactly which growth plate is responsible.

Does every foal need surgery?

Definitely not.

In the foal’s first few weeks, your farrier plays a key role (not something you hear vets say too often!) 

• Corrective trimming:
  • In order to load the growth plates with a more axial alignment and thus promote straighter load bearing through the limb, the first line of treatment is to trim the hoof capsule so that it is well balanced. This means trimming the lateral aspect of the hoof capsule in cases of valgus deformity and the medial aspect of the hoof capsule in animals with varus deformities.                                              
• Hoof extensions:
  • For lateral deviations, a medial hoof extension should be fitted extending approximately 3 cm out from the hoof capsule. For medial deviations, a lateral hoof     

Careful monitoring and controlled exercise is of paramount importance at this stage. 

Alas… some wonky legs refuse to straighten with what we call ‘conservative management’… enter the surgeon…

Why timing matters

Growth plates don’t stay open forever.

Timing of intervention

One of the biggest factors influencing treatment success is time. Surgical correction relies on the growth plate still being active, so the earlier a significant deformity is recognised, the more options we have.

As a practical guide:

Joint:	Growth plates close:	Intervention time:
Fetlocks	6 months	1 – 3 months old
Knees	20 – 24 months	7 – 16 months
Hocks	17 – 24 months	6 – 15 months

There are a number of surgical options available to us in the search for straighter foal limbs. The most popular method is most likely the transphyseal screw. Aka placing a single screw across the growth plate whilst the foal is under a general anaesthetic. This screw is applying the brakes as we mentioned earlier and can be removed rather simply and often without the need to go back to a referral clinic.