- Discussion:
- index finger is most commonly involved, often found in older pts w/
degenerative arthritis;
- Etiology:
- muscular contracture or trauma;
- collateral ligament or volar plate tethering on prominent MP head or osteophyte
(on either side or volar aspect of metacarpal head);
- torn palmar plate;
- metacarpal head fracture;
- loose body
- abnormal
sesamoids
- Diff Dx:
- must be differentiated from
Trigger Finger which is caused by
stenosis of flexor tendon sheath in region of A1 pulley;
- in
Trigger Finger, catching characteristically occurs in PIP joint,
where w/ "MP Locking", locking is in MP joint;
- Exam:
- on exam, flexor tendons are intact, & active finger flexion may be nearly normal;
- MP joint may not allow extension past
40 to 50 deg of MP flexion;
- attempts to straighten the digit are painful;
- X-ray:
- consider oblique x-rays of hand to demonstrate bony osteophyte;
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Locking of the metacarpophalangeal joint of the thumb.
