Ulnar deviation is also known as ulnar drift. This hand condition occurs when your knuckle bones, or metacarpophalangeal (MCP) joints, become swollen and cause your fingers to bend abnormally toward your little finger.
It’s called ulnar deviation because your fingers bend in the direction of the ulna bone in your forearm. This bone is on the outermost edge of your arm on each side.
This condition won’t necessarily keep you from using your hands for daily tasks, such as gripping objects or tying your shoes. But over time, you may find some activities harder to do. You may also not like the way your hands look as they bend and distort.
Keep reading to learn more about the symptoms, how it’s diagnosed, and more.
Swelling in your knuckles is one of the most noticeable symptoms of ulnar deviation. You may also find that your fingers, especially your middle and index fingers, bend toward your pinky finger.
As the condition progresses, you may experience:
- abnormal heat around your wrist, hand, and finger joints
- pain or tenderness around your wrist, hand, and finger joints, especially when you move or flex your fingers
- inability to fully flex your fingers or make a fist
- tightness of your hand muscles
- inability to pick up objects or do certain tasks with your index finger and thumb, such as using zippers or squeezing objects
Ulnar deviation is often linked to types of arthritis, especially rheumatoid arthritis.
Other symptoms that go along with these conditions include:
- abnormal weight loss
- stiffness in your hand joints and similar joints, such as your toe joints
- feeling of exhaustion
One of the most common causes of ulnar deviation is rheumatoid arthritis (RA). RA is an autoimmune disorder that causes your immune system to target your joint tissue.
With RA, inflammation can cause damage to both the MCP joint and the areas surrounding the joint. Over time, this can cause your joints to wear away and your bones to erode. This may eventually make your hands look distorted.
RA doesn’t have a specific known cause. It’s thought that your genes can trigger the condition when you’re exposed to certain environmental factors, such as infection.
Osteoarthritis (OA) is also known to cause ulnar deviation. Unlike RA, OA isn’t caused by your immune system. It’s caused by your joint cartilage gradually wearing away due to overuse or age. When the cartilage has worn away significantly, your bones start to rub together in the joint. This damages the joints and can cause them to become distorted and bend.
Other causes of ulnar deviation include:
- psoriatic arthritis, a type of chronic arthritis also caused by your immune system attacking your joints
- lupus, another autoimmune condition that can cause joint damage associated with arthritis and other symptoms such as fevers and fatigue
After reviewing your medical history, your doctor will perform a physical exam and assess your symptoms.
They may ask you to move, extend, or flex your hand and fingers to observe your range of motion. If your fingers move abnormally in the ulnar direction or make a “clunking” noise when you move them, it may indicate ulnar deviation.
Your doctor may also want to take X-rays of your hands to look more closely at the swelling and deviation in your fingers. Your doctor can also examine your ligaments and other tissue surrounding the joints.
Ulnar deviation is chronic and progressive. Treatment aims to help manage your symptoms and maintain your quality of life.
Exercise treatment can also help you manage your symptoms. Depending on the severity of your ulnar deviation, treatment may range from simple wrist, hand, and finger exercises you can do at home to wearing a splint to keep your fingers in place.
Talk to your doctor about the best exercise options for you. They may refer you to a physical therapist or occupational therapist to help teach the correct way to do these exercises.
Your doctor may also recommend home treatments, such as hot or cold therapy, to help relieve some of your symptoms. For example, applying heat to your fingers while they’re extended can help increase your range of movement. Applying ice to the joints can help reduce pain and swelling.
In more severe cases, laser treatment may help reduce pain and tenderness. Transcutaneous nerve stimulation, which uses electricity to treat pain, may also help reduce the pain associated with ulnar deviation.
Your outlook depends on how severe your ulnar deviation is or how far it’s progressed. You may be able to relieve your symptoms without any impact on your daily life. In some cases, with enough physical therapy and treatment, your symptoms may not be noticeable at all.
If an underlying condition, such as RA or lupus, is causing your ulnar deviation, your doctor may recommend a long-term treatment plan to manage your symptoms and improve your overall health. If left untreated, this underlying condition may cause additional complications.
If your doctor diagnoses you with ulnar deviation early enough, they may recommend that you wear splints to keep your fingers from bending any farther than they already have.
Splints that can help slow disease progression include:
- hand-resting splints, which you usually wear at night on your wrist and fingers to relax your MCP joint and reduce inflammation and pain
- MCP joint splints, which you can wear during the day to support your fingers and help your grip objects with less pain
- exercise splints, which support your MCP joint when you extend or flex your fingers to help reduce joint tightness or inflammation
You can also make some lifestyle changes to avoid causing too much strain on your joints:
- use both hands to hold heavy objects
- avoid using handles on objects such as pots or coffee mugs
- try not to do too many activities that move your fingers in the ulnar direction, such as using doorknobs or opening jars