Fractures of the Radius and Ulna in Dogs and Cats
- Mathieu
- 2 days ago
- 5 min read
Sudden lameness following a fall or injury may indicate a fracture of the forearm
Is your dog or cat suddenly limping, refusing to put a paw on the ground, or appearing to be in a lot of pain after a fall, an accident, or a misstep? A fracture of the radius and ulna could be the cause.
The radius and ulna are the two bones that make up the forearm, located between the elbow and the carpus—the equivalent of the wrist in humans. A fracture can affect one or both of these bones and cause significant pain, swelling, deformity of the limb, or an inability to use it normally.
If your pet shows signs similar to those described, a prompt veterinary consultation is recommended to confirm the fracture with X-rays and determine the most appropriate treatment based on your pet’s age, size, and the location and complexity of the injury.
The forearm of dogs and cats consists of two bones: the radius and the ulna. They connect the elbow to the carpus (the equivalent of our wrist) and allow the animal to support its weight when walking, running, or jumping.
Since these two bones work together, a fracture often affects both at the same time. When they are broken, it becomes very difficult, if not impossible, for the animal to put weight on its paw.
Is your dog limping after a walk? Did your cat take a bad fall? Or was your pet unfortunately involved in an accident? In all these situations, a fracture is a possibility. Fractures of the forearm (the radius and ulna) are, in fact, among the most common injuries following trauma, in both dogs and cats.
When an animal arrives at the clinic with a suspected fracture, the veterinarian begins with a thorough physical examination. Afterward, X-rays are almost always necessary.
Why? Because an X-ray doesn’t just confirm that there’s a fracture. It also provides a wealth of information that will help determine the best course of treatment.
For more details on surgery, recovery, and the prognosis for radius-ulna fractures, see our fact sheet on this topic:
Here's what the veterinarian looks for:
Which bones are broken?
The radius, the ulna, or both?
At what height are they broken?
Near the elbow, in the center, or near the wrist?
Is the fracture simple or complex?
Even though these two bones are next to each other, they are not always fractured together. It is therefore important to know exactly which ones are affected.
What does the fracture look like?
Not all fractures are the same! The fracture line can be:
transverse: a very clean, straight fracture;
oblique: the fracture line runs across the bone at an angle, “diagonally”;
spiral: often caused by a twisting motion, much like when you twist a branch.
Some fractures are also much more complex. Sometimes, the bone is broken into a few large pieces. Other times, it is literally shattered into many fragments. In general, the more pieces there are, the more difficult the repair is.
Where is the bone broken?
A fracture can occur in the middle of the bone or near one of its ends. A fracture can be:
Proximal epiphyseal
Proximal metaphyseal
Proximal diaphyseal
Mid-diaphyseal
Distal diaphyseal
Distal metaphyseal
Distal epiphyseal
It may seem like a minor detail, but where the bone is broken directly affects the type of surgery and how it will heal.
Does the fracture involve a joint? A fracture can be:
articular, when it affects a joint
non-articular
If the fracture involves a joint, the surgery becomes even more precise.
Why?
This is because the articular surfaces must be perfectly realigned to allow the animal to regain optimal function and reduce the long-term risk of osteoarthritis. Osteoarthritis will inevitably develop in a joint affected by an unstable joint fracture.
Is the skin intact? A fracture can be:
closed, when the skin is intact;
open, when a bone or the wound is exposed to the outside.
Open fractures require prompt treatment because they carry a much higher risk of infection.
Did the bone fragments move?
After a fracture, the different bone fragments may remain well aligned... or may shift completely out of place. The more they are displaced, the more surgery will be needed to realign them so that the bone heals properly. The fracture may be:
Slightly displaced
Moderately displaced
Severely displaced
Surgeons would describe it this way: A comminuted fracture of the proximal shaft of the radius and ulna, non-articular, closed, and slightly displaced.
That might seem like a lot of big words all at once! Yet each of these terms conveys essential information about the injury. In just a few words, the surgeon knows which bones are affected, where they’re broken, how many fragments there are, whether a joint is involved, whether the skin is open or not, and whether the bones have shifted. In short, this description helps determine the most appropriate treatment and gives your pet the best chance of regaining a fully healthy limb.
The animal has been stabilized, X-rays have been taken, and it’s time for surgery. How do you choose the type of stabilization to use?
The goal is always the same:
to return the bone fragments to their normal position (reduction);
to restore their alignment;
to maintain this position until healing is complete.
A fracture can be stabilized with a cast or a bandage. However, not all fractures heal well with external stabilization (bandage, splint, cast). Very often, internal (surgical) stabilization is necessary. Implants can then be placed on the bone—and inside the bone!
In the example below, a rod is placed in the ulna and a plate is screwed onto the radius.
Although the X-ray above looks a little dramatic 😉 and all this equipment may seem intimidating at first glance, rest assured: recovery is generally comparable to that of many other orthopedic surgeries commonly performed in veterinary medicine.
For all fractures, bone healing depends on several factors. The animal’s age, the type of fracture, the quality of the surgical reduction, and adherence to postoperative recommendations all play an important role in the speed and quality of recovery. Every patient is unique, which is why the follow-up plan is tailored to their specific situation.
In conclusion
The sooner an animal is evaluated and treated, the greater the chances of a full recovery. Early intervention not only helps limit pain and damage to surrounding tissues but also offers a wider range of treatment options.
Conversely, a fracture left untreated for several days can become more difficult to repair. Bone fragments may shift further, soft tissues may sustain more damage, and surgical planning may become more challenging. In some cases, a significant delay can even compromise the prognosis or require a more complex procedure.
If your veterinarian suspects a fracture, a prompt referral to a surgical department is therefore strongly recommended. Early intervention maximizes the chances of a full recovery and a rapid return to normal function of the affected limb.
