Hand / Fingers
Swan Neck Deformity
백조목 변형
PIP hyperextension with DIP flexion resembling a swan's neck
- How common
- Common in rheumatoid arthritis
- Typical age
- Age 40+
What is it?
Volar plate laxity, PIP synovitis, or mallet finger cause PIP hyperextension with compensatory DIP flexion.
Commonly affected: Index through little fingers; after RA/trauma
How it develops
- Volar Plate LaxityPIP volar plate weakens or synovitis stretches it
- Lateral Band Dorsal MigrationLateral bands shift dorsal to PIP axis
- PIP HyperextensionLateral bands now hyperextend PIP
- DIP FlexionLoss of terminal tendon tension flexes DIP
Symptoms
- PIP hyperextensionPIP bent backward
- Difficulty making fistPIP flexion triggers/locks
- DIP flexionFingertip flexed
- Triggering sensationClicking/catching with PIP flexion
- Underlying arthritisSystemic RA symptoms
How it is examined
- Bunnell testPIP flexion varies with MCP position — assesses intrinsic tightness
- PIP hyperextensionMeasure PIP hyperextension angle
- DIP flexion angleMeasure DIP flexion posture
- Underlying cause assessmentDifferentiate RA, trauma, mallet, CP etc.
Imaging
Lateral X-ray shows PIP hyperextension + DIP flexion; assess underlying arthritis.
- PIP hyperextension posture
- DIP flexion
- Possible RA changes (erosions, narrowing)
- Volar plate calcification
MRI assesses volar plate laxity, synovitis, and lateral band position.
- Volar plate laxity/tear
- PIP synovitis
- Dorsal lateral band migration
- Extensor tendon pathology
Non-surgical care
- Figure-8 (silver ring) splintPrevents PIP hyperextension
- Treat underlying causeDMARDs/biologics for RA
- Hand therapyIntrinsic stretching, ROM exercises
- NSAIDs/synovitis injectionSteroid injection for PIP synovitis
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Fixed deformity, functional impairment, failed conservative
Procedures that may be discussed
- Lateral band relocation (SORL)
- PIP volar plate tightening
- PIP arthrodesis (stiff joint)
Outlook
Early intervention prevents progression; RA disease control is key.