Cubitus valgus is a deformity in which the forearm is angled out away from the body when the arm is fully extended. When it affects both arms, it’s known as cubitus valgus bilateral.

When your palm is facing upward and your arm is extended, you may have cubitus valgus if your carrying angle, or the degree to which your arm is angling away from your body, exceeds 15 degrees.

However, it’s possible to be diagnosed with cubitus valgus with a carrying angle anywhere between 3 and 29 degrees. The angle is often more pronounced in women.

This condition doesn’t always need to be treated, but in some people, it can compress the nerves in the arm, causing complications.

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People with cubitus valgus have a deformity that causes the forearm to be angled away from the body more than normal when the arm is fully extended. | Photo: Mikael Häggström

There are two possible causes for cubitus valgus: a congenital condition or a fracture.

The two congenital conditions that commonly cause cubitus valgus are Turner syndrome and Noonan syndrome.

Turner syndrome is a chromosomal disorder in which a female is born with only one X chromosome. People with Turner syndrome experience a number of other symptoms, including short stature and delayed puberty. Treatment usually involves hormone replacement therapy.

Noonan syndrome is another genetic disorder that results in delayed development. It’s usually caused by a genetic mutation, but sometimes doctors aren’t sure why it develops. While there’s no cure for Noonan syndrome, there are a number of treatments that can help minimize its effects.

Cubitus valgus is a known cause of ulnar neuropathy. This is a disorder involving the ulnar nerve, which is one of the three main nerves in your arm.

Ulnar neuropathy most often occurs when the ulnar nerve becomes compressed or irritated, causing numbness, tingling, and occasionally weakness. Most of the time treatment involves limiting physical activity and wearing a brace. However, if these conservative treatments don’t work, surgery may be necessary.

Cubitus valgus can also lead to a condition called tardy ulnar nerve palsy, a type of ulnar neuropathy. This is a chronic condition that is commonly associated with cubitus valgus.

Ulnar nerve palsy is progressive, in that it usually gets worse over time. You may experience a loss of sensation in your fingers, especially your ring and little finger, as well as loss of coordination, tingling and burning, pain, and weakness.

There are a number of treatments for the symptoms of ulnar nerve palsy, including over-the-counter medications and physical therapy.

If cubitus valgus isn’t compressing your ulnar nerve, you probably won’t need treatment.

In most cases, cubitus valgus is treated by one of two procedures: osteotomy or fixation. Osteotomy is a process in which your doctor cuts the bone in order to reshape it, thereby changing its alignment.

A particular type of osteotomy called distraction osteogenesis has been used to treat cubitus valgus in children. This operation works by making a longer bone out of a shorter one. The bone that is cut during surgery is pulled apart using a device called a distractor, a process that is only mildly painful. New bone will grow in the gap created by the distractor, creating a longer bone in place of a shorter one.

Fixation is the process by which your doctor will reconnect the bones of the elbow, usually following a fracture.

In most cases, you will only need to seek treatment if cubitus valgus is compressing your ulnar nerve.

However, it’s important to seek treatment if you begin to experience pain, numbness, or weakness in your arms or fingers. This could be a sign of nerve damage.