June 2025 Newsletter
Pelvis Fracture
In our practice, racehorses in training make up the majority of our caseload.
These high-powered athletes are the premier league footballers of the equine world. Fast, nimble, agile and like footballers sometimes a little fragile!
As it is in any performance sport, human or equine, injuries will occur (I know myself from years of playing rugby). Of all the woes that put racehorses on the sidelines, musculoskeletal injuries rank as the highest. Amongst these injuries, fractures account for around 30% in National Hunt racehorses (Pinchbeck et al, Vet Journal 2004). Statistically, a NH racehorse in the UK is likely to have a fracture somewhere between 0.3 and 2.2 times per 1000 racecourse starts. Another statistic is that for a NH racehorse in the UK there is 1.15 fractures per 100 horse months in training (ARVS summer scientific 2025). So really overall, it’s a low number, but as always it can be improved upon!
One of the most common fractures we see in NH racehorses is a pelvic fracture.
The pelvis connects the spine to the hind limbs. As you can see on the images below, the right and left-hand sides of the pelvis are a mirror image of each other with the sacrum in the middle.
There are many areas of attachment for muscles, tendons and ligaments. The massive musculature in and around the pelvis generates enormous forces to propel the horse forward at high speeds.
But what causes the pelvis to fracture?
A racehorse’s skeletal system is continually modelling and remodelling throughout their life. Bone formation and resorption are always ongoing and is required for healthy bones to respond to changes. In an ideal scenario, formation and resorption are in a balanced state. However, many things can alter this balance such as increased work load, growth, or even some medications.
When this balance is disturbed a fracture (such as a pelvic fracture) is more likely to occur!
Pelvic fractures can occur in any area of the pelvis and have various causes such as trauma, repetitive stress, falls or even doing the splits. They can range from simple stress fractures to catastrophic injuries. The horse can be mildly lame to non-weight bearing lame. (The idea that they are always lame at walk with any pelvis fracture is definitely not true!!!)
How do we diagnose a pelvic fracture?
First and foremost, a detailed clinical exam is carried out where we will assess the horse in them stable and palpate all the relevant structures. This can be really helpful and in some cases you will have a fair idea what’s going on before you even leave the stable. For example, there may be some obvious muscle atrophy if the horse has been lame for a period of time.
After the clinical exam, depending on how painful the horse is, we might see the horse trot/walk.
This allows us to assess their locomotion and can often give more hints as to what’s going. E.g. horses with a stress fracture of the ileal wing/ third trochanter often trot “on three tracks”. The level of lameness usually depends on the location and severity of the fracture but is often quite variable. I have seen some horses with small stress fractures of the pelvis be almost sound in trot, while others can be lame at walk.
Once we have finished the clinical exam and assessed the horse’s movement we move on to using our Ultrasound scanner to examine the pelvis.
Ultrasonography is really useful for assessing the external pelvis. It’s quick and easy and doesn’t annoy the horse too much! It’s great for giving an accurate diagnosis for many types of pelvic fractures, however, sometimes it can fall short. In these cases, the horse may be sent for a bone scan.
Treatment of pelvic fractures
Treatment for pelvic fractures is generally conservative.
In the early stages it is vital to establish the severity of the fracture in order to be aware of any potential for a large displacement of the fracture that could be fatal. In some cases, if they lie down it can be a big problem, hence why we sometimes suggest that horses with pelvic fractures are cross tied for a period of time.
In all cases the horse will have a period of box rest, generally 4-6 weeks depending on the location of the fracture, the severity of lameness and the degree of displacement of the fracture fragments. Though box rest is beneficial in the healing process, changes in bone mineralisation during long layups can have a negative effect on the horse in the long run. For this reason, we try to keep box rest to the minimum that is needed to allow the horse to heal.
After a period of box rest, they usually undergo a controlled exercise regime that can last anywhere from 6-12 weeks.
Throughout the recovery period repeat ultrasound examinations are important to assess how well the fracture is healing.
In my experience most horses will return to racing after a pelvic fracture. This can take anywhere from 12 weeks to 6 maybe even 12 months dependant on the type of injury.
Here are some of the types of pelvic fractures we encounter in our practice:
Ileal wing – most common type of fracture that we see. Usually 3/5 lame (sometimes less, sometimes more) and often “on three tracks”. They can displace but that’s rare enough in my opinion. Often these horses are back walking after 4 weeks and back riding by 12 weeks. The prognosis is generally good if there’s not massive displacement.
Tuber Coxae – another common site of fracture. They are usually very lame for a few days but improve quite rapidly. This fracture can give the appearance of a “knocked down hip”. This is due to the pull of the Tensor Fascia Lata on the lateral fracture fragments that distorts the anatomy of the pelvis. In my experience these take a bit longer to return to training in comparison to an ileal wing but most of them do make it back to racing, albeit with a wonky looking behind! In some rare cases, a bit of a bone chip/ fragment may pierce the skin and delay healing or cause infection. This is the rare case in which surgery is required for a pelvic fracture!
Ilial shaft fractures – the horse is usually extremely painful and non-weight bearing on the effected limb. They are prone to causing a bleed by severing the large blood vessels that traverse the ileal shaft. This type of fracture can be life threatening. Often require cross tying to avoid the fracture displacing further. Usually have a poor prognosis.
Tuber Ischii – relatively uncommon. The horse is usually moderately lame. Caused by trauma or avulsion by the pull of the hamstrings. When the hamstring is involved, there is often a fair amount of swelling. These tend to recover quite well and quite quickly.
Tuber Sacrale – otherwise known as hunters bump. I have only seen one acute case of this and it was very sore to palpate but not very lame. Usually caused by trauma but can also be stress related. Prognosis is good!
Third Trochanter – while not technically a part of the pelvis (it’s part of the femur) it has an attachment point for the glute muscles and it’s just below the hip so I am going to include it here.
These are usually moderately lame and classically “on three tracks”. They tend to recover quickly and well!
Pubis– very uncommon. Can be caused by doing the splits. I’ve only seen one and it was quite lame. Usually diagnosed by Bone Scan.
Sacrum – Again not technically part of the pelvis. I have only seen one and it was very lame but improved quite quickly. However, the horse had massive gluteal muscle atrophy that took quite a while to correct. Luckily the horse in question had a trainer and a physio dedicated to the job and returned to racing and won a few times!
