Historical Overview
- In 1916, Harvey Cushing first described symphalangism, or ankylosis of the interphalangeal (IP) joints of the fingers.1,2
Description
- Symphalangism is diagnosed primarily through observation. Symphalangism involves a stiffness of either the proximal interphalangeal (PIP) or the distal interphalangeal (DIP) joints of the fingers, with PIP joint involvement being more common. Fused phalanges of the ring and little finger are the most common.3,4
- There are three grades of symphalangism: fibrous, cartilaginous and bony.2
Pathophysiology
- Symphalangism may arise from a spectrum of syndromes, including Apert’s, Poland’s and multiple synostoses.4
Instructions
- Obtain an accurate and complete patient history. Ask if the patient experiences any difficulties with fine manual dexterity in the affected fingers. These difficulties may affect activities such as writing and playing musical instruments.
- Examine the affected fingers for stiffness and difficulty making a fist.
- Check for absence of volar skin creases at the affected joint(s).
- Examine the contralateral hand; symphalangism can be bilateral.
Variations
- Determine whether the symphalangism is fibrous, cartilaginous, or bony at the time of the exam. According to the patient’s age at diagnosis, the same joint can be classified as either fibrous, cartilaginous, or bony.2
Related Signs and Tests
- Range of motion (ROM), active
- Range of motion (ROM), passive
- Grip strength
- Joint exam
- Skin test
- Radiographs
- Magnetic resonance imaging (MRI), without contrast
Diagnostic Performance Characteristics
- Beginning in late childhood, radiographic evidence may be used to improve reliability.3