Crooked Front Legs in Dogs – Short Ulna, Carpus Valgus & Radius Curvus Explained

Some dogs develop shortened or misaligned front legs during growth. The terms Short Ulna, Carpus Valgus and Radius Curvus describe typical malpositions of the front limbs caused by growth disturbances. The following article explains what lies behind this, how to recognise the changes and what treatment options exist.

How does bone growth work?

The dog’s front legs consist of two long bones: the radius and the ulna. Both grow from so-called growth plates. Disruptions in this process – for example due to injuries, incorrect loading or genetic factors – can cause one of the bones to grow more slowly or stop growing altogether. The result: the bones fall out of balance and the limbs deform.

Short Ulna – when the ulna remains too short

In Short Ulna Syndrome, the ulna does not grow at the same rate as the radius. Because it is anchored at the elbow joint, it pulls the radius with it, leading to malpositions. Typical consequences:

• crooked front legs
• twisted or outward-facing paws
• Pain under load and lameness

If left untreated, the condition can lead to joint problems and osteoarthritis in the long term.

Carpus Valgus – paws turning outwards

In Carpus Valgus, the front carpal joint (carpus) bends outwards, causing the paws to stand at an angle. This places uneven stress on the joints. Causes may include:

• a short ulna syndrome
• weak connective tissue or overstretched ligaments
• Nutritional errors during growth, e.g. oversupply of calcium

Mild cases sometimes stabilise on their own; more severe forms must be treated to avoid long-term consequences.

Radius Curvus – a bent forearm bone

Radius Curvus refers to a condition where the radius grows curved. Uneven bone growth is often the cause here too, e.g. due to blocked growth plates. Consequences:

• clearly visible bending of the front legs
• Shortening of the leg
• Pain and problems under load

How can I recognise malalignments?

As a dog owner, you should become alert if your dog:

• developed visibly crooked front legs
• limps or appears stiff when walking
• frequently turns the paws outwards
• gets tired quickly when playing or walking

How does the vet make the diagnosis?

The vet will first examine the gait and limb alignment. To determine the cause precisely, X-rays are necessary. In complex cases, CT or MRI scans help to plan surgery accurately.

Treatment options

Conservative

In mild malpositions, rest, controlled training and physiotherapy may already help. Orthopaedic aids such as booties or bandages provide additional relief. An adapted nourishment during growth is also important to avoid negatively affecting bone growth.

Surgical

In many cases, surgery is the only way to prevent a permanent malposition. Typical procedures:

• Corrective osteotomy: targeted transection and straightening of the bone
• Growth guidance: interventions at the growth plate in young dogs
• Elongation or shortening of bones using special fixators

Prognosis

The earlier the malposition is detected, the better the chances. With timely correction, dogs can lead a completely normal and active life. If left untreated, pain, incorrect loading and premature osteoarthritis are likely.

Prevention – what you can do

• Do not overload young dogs (no extreme jumping or climbing stairs).
• Paying attention to a balanced diet – neither too much nor too little calcium and energy.
• Regular veterinary check-ups, especially for large breeds.