SymptomBones, joints & muscles
Finger Deformity: Bent, Curled or Misshapen Fingers
A finger deformity is a finger that is bent, curled, crooked, swollen at the joints or stuck in an abnormal position. The most common causes are osteoarthritis, rheumatoid arthritis, tendon injuries such as mallet finger, trigger finger and Dupuytren's contracture. Some deformities follow a jammed or broken finger. Many can be corrected or stopped from worsening if treated early, so a new finger deformity, especially after an injury, should be assessed within days.
Also called: Deformed finger, misshapen finger, crooked finger, finger joint deformity
At a glance
- What it is
- A finger with an abnormal shape, angle or fixed position.
- Most common causes
- Osteoarthritis, rheumatoid arthritis, tendon injuries, trigger finger and Dupuytren's contracture.
- Injury-related
- Mallet finger, boutonniere deformity and poorly healed fractures.
- Key point
- Tendon injuries do best when splinted within days.
- Treatment
- Splinting, hand therapy, steroid injections, arthritis medicines and surgery.
When to get help
Call 911 or go to the ER
- A finger bent at an obvious odd angle after an injury, or a cut with bone or tendon visible
- A finger that is cold, white or blue, or numb after an injury or crush
See a doctor within a day or two
- A fingertip that suddenly droops and cannot be straightened after a jam or knock
- A middle joint that cannot straighten after an injury, with swelling over the top
- A red, hot, very swollen finger or joint with fever, or after a bite or puncture wound
- A deep cut on the palm side of a finger with inability to bend it
Book a routine appointment
- Several swollen, stiff finger joints with morning stiffness lasting over 30 minutes
- A finger that clicks, locks or catches when bending
- A lump in the palm with a finger gradually pulling into the palm
- Bony bumps on finger joints that are painful or changing
Types of finger deformity
| Deformity | What it looks like | Usual cause |
|---|---|---|
| Mallet finger | Fingertip droops and cannot be straightened actively | Tendon tear at the fingertip from a jam (ball hitting fingertip) |
| Boutonniere deformity | Middle joint bent down, fingertip bent back | Tendon injury over the middle joint, or rheumatoid arthritis |
| Swan-neck deformity | Middle joint bent back, fingertip bent down | Rheumatoid arthritis, loose ligaments, untreated mallet finger |
| Trigger finger | Finger catches or locks in a bent position, then snaps straight | Thickened tendon catching in its sheath |
| Dupuytren's contracture | Ring or little finger gradually pulled into the palm | Thickened cords in the palm tissue |
| Heberden's and Bouchard's nodes | Bony lumps at the end and middle finger joints | Osteoarthritis |
| Ulnar drift | Fingers angle toward the little finger at the knuckles | Rheumatoid arthritis |
| Rotational or angulated finger | Finger overlaps its neighbor when making a fist | Poorly healed fracture |
| Clinodactyly / camptodactyly | Finger curves sideways / middle joint fixed bent from childhood | Congenital, often inherited |
Causes of finger deformity
Arthritis
- Osteoarthritis: wear of joint cartilage causes bony enlargement of the end joints (Heberden's nodes) and middle joints (Bouchard's nodes), sometimes with fingers angling sideways. Very common after 50, especially in women. The base of the thumb is often affected.
- Rheumatoid arthritis: an autoimmune disease that inflames the lining of the knuckles and middle joints on both hands. Without treatment it can damage ligaments and tendons, causing ulnar drift, swan-neck and boutonniere deformities. Modern treatment has made severe deformity much less common.
- Psoriatic arthritis: swelling of a whole finger ("sausage finger"), nail changes and end-joint damage.
- Gout: chalky lumps (tophi) on finger joints after years of untreated gout.
Tendon and soft tissue problems
- Tendon injuries cause mallet finger and boutonniere deformity. They are easy to dismiss as a "jammed finger", but without splinting they can become permanent.
- Trigger finger is more common in people with diabetes and in women over 40.
- Dupuytren's contracture is more common in men of Northern European ancestry, with age, diabetes, smoking and heavy alcohol use, and runs in families.
Fractures and dislocations
A broken finger that heals in a twisted or angled position (malunion) causes scissoring when you make a fist. Dislocations of the middle joint can damage the stabilizing ligaments.
Nerve problems
Nerve damage from a cut, stroke, ulnar nerve compression at the elbow or diabetes can cause muscle imbalance and a "clawed" hand, with the ring and little fingers curled.
Present from birth
Curved little fingers (clinodactyly), fixed bent fingers (camptodactyly), extra or joined fingers. Most cause no functional problem.
How a finger deformity is diagnosed
The doctor will ask whether there was an injury, how quickly it developed, which joints are affected, and about stiffness, swelling and family history. They will check active and passive movement of each joint, tendon function, sensation and blood flow. Tests may include:
- X-rays for fractures, arthritis and joint alignment
- Ultrasound for tendons and trigger finger
- Blood tests for rheumatoid factor, anti-CCP antibodies, inflammation markers and uric acid
Treatment
Splinting and hand therapy
- Mallet finger: a splint holding the fingertip straight, worn continuously for 6 to 8 weeks. Bending the tip even once during that time can restart healing.
- Boutonniere: a splint keeping the middle joint straight for about 6 weeks.
- Arthritis: splints rest painful joints and support the base of the thumb. A hand therapist can teach joint protection and exercises.
Injections and medicines
- Steroid injection into the tendon sheath often cures trigger finger.
- Rheumatoid arthritis medicines (methotrexate and biologics) control inflammation and prevent further deformity.
- Pain relief: acetaminophen (paracetamol), or anti-inflammatory gels or tablets, following the label.
Procedures and surgery
- Dupuytren's: needle release of the cord or surgical removal when a finger cannot lie flat on a table.
- Trigger finger release if injections fail.
- Tendon repair or reconstruction for some injuries.
- Joint fusion or replacement for severe arthritis.
- Correcting a malunited fracture by realigning the bone.
Frequently asked questions
What causes finger deformity?
The most common causes are osteoarthritis, rheumatoid arthritis, tendon injuries such as mallet finger, trigger finger and Dupuytren's contracture. Poorly healed fractures, nerve damage, gout and conditions present from birth are other causes.
Can a finger deformity be fixed?
Often, yes. Mallet finger and boutonniere deformity usually heal well with early splinting. Trigger finger responds to injections or a small operation. Dupuytren's and arthritis deformities can be improved with procedures or surgery, though long-standing damage may not fully correct.
What does a rheumatoid arthritis finger deformity look like?
Typical patterns are fingers drifting toward the little finger at the knuckles (ulnar drift), swan-neck deformity, and boutonniere deformity. Joints are often swollen on both hands. Early treatment with disease-modifying medicines prevents most of these changes.
Should I see a doctor for a jammed finger that looks bent?
Yes, within a few days. A fingertip that droops or a middle joint that will not straighten may be a tendon injury that needs splinting promptly. Left untreated, it can become a permanent deformity.
Sources
This guide was written from current patient and clinical guidance, including:
- American Society for Surgery of the Hand: Hand conditions (mallet finger, trigger finger, Dupuytren's contracture)
- American Academy of Orthopaedic Surgeons (OrthoInfo): Arthritis of the hand
- American College of Rheumatology: Rheumatoid arthritis
- NHS: Dupuytren's contracture
- MedlinePlus: Finger injuries and disorders